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Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Copyright copy 2010 American Scientific Publishers
All rights reserved
Printed in the United States of America
Journal ofNanoscience and Nanotechnology
Vol 10 5507ndash5519 2010
Electrospinning of Nanomaterials and Applications in
Electronic Components and Devices
Jianjun Miao124 Minoru Miyauchi4 Trevor J Simmons24Jonathan S Dordick134lowast and Robert J Linhardt1234lowast
1Departments of Chemical and Biological Engineering 2Chemistry and Chemical Biology 3Biology4Center for Nanotechnology and Center for Biotechnology and Interdisciplinary Studies
Rensselaer Polytechnic Institute Troy NY 12180 USA
Electrospinning of nanomaterial composites are gaining increased interest in the fabrication ofelectronic components and devices Performance improvement of electrospun components resultsfrom the unique properties associated with nanometer-scaled features high specific surfaceareas and light-weight designs Electrospun nanofiber membrane-containing polymer electrolytesshow improved ionic conductivity electrochemical stability low interfacial resistance and improvedchargendashdischarge performance than those prepared from conventional membranes Batteries withnon-woven electrospun separators have increased cycle life and higher rate capabilities than oneswith conventional separators Electrospun nanofibers may also be used as working electrodes inlithium-ion batteries where they exhibit excellent rate capability high reversible capacity and goodcycling performance Moreover the high surface area of electrospun activated carbon nanofibersimproves supercapacitor energy density Similarly nanowires having quasi-one-dimensional struc-tures prepared by electrospinning show high conductivity and have been used in ultra-sensitivechemical sensors optoelectronics and catalysts Electrospun conductive polymers can also per-form as flexible electrodes Finally the thin porous structure of electrospun nanofibers provides forthe high strain and fast response required for improved actuator performance The current reviewexamines recent advances in the application of electrospinning in fabricating electronic componentsand devices
Keywords Carbon Nanofiber Electrode Separator Electrolyte Nanowire SupercapacitorsActuator Lithium Ion Battery
CONTENTS
1 Introduction 5507
11 Electrospinning History and Overview 5507
12 Electrospinning in Energy Applications 5509
13 Electrospinning Methods and Principles 5510
2 Applications of Electrospinning Preparing Electrical
Components and Devices 5510
21 Electrospun Insulators Separators and Electrolytes 5510
22 Electrospun Electrodes 5511
23 Wires and Nanowires 5513
24 Supercapacitors 5515
25 Actuators 5516
3 Challenges and Open Questions 5517
4 Conclusion and Prospects 5518
Acknowledgments 5518
References and Notes 5518
lowastAuthors to whom correspondence should be addressed
1 INTRODUCTION
11 Electrospinning History and Overview
Electrospinning first appeared in 1934 as a new patented
process for spinning small diameter fibers12 Prototype
electrospinning devices were capable of collecting threads
of aligned fibers By 1969 Taylor developed a jet form-
ing process3 and not long after the impact of experimental
parameters on electrospun fiber structuresproperties was
established4 resulting in polyethylene and polypropylene
melts that could be electrospun into fibers56 Very little
additional work on electrospinning was undertaken until
the early 1990s when electrospinning was applied to a
broad range of polymers yielding porous fibers Increased
popularity of the term electrospinning coincided with a
dramatic increase in the number of annual publications
at the beginning of the 21st Century78 Many polymers
J Nanosci Nanotechnol 2010 Vol 10 No 9 1533-48802010105507013 doi101166jnn20103073 5507
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
have been electrospun into fiber mats and membranes
New technologies have been introduced for electrospin-
ning such as double needle electrospinning (Fig 1(a))
which can fabricate fibers from two different compo-
nents simultaneously such as polymers or polymers and
solids combinations or solndashgels9 The resulting fibers
Jianjun Miao received his BS degree in Chemical Engineering from East China University
of Science and Technology (ECUST) in 2001 and PhD degree in Chemical Engineering
from University of Connecticut in 2009 He joined Professor Linhardtrsquos group at Rensselaer
Polytechnic Institute as a postdoctoral fellow in 2009 His research interests include electro-
spinning nanostructured materials bionanomaterials and nanostructure-based devices He
has published nine peer-reviewed papers in the area of materials chemistry
Minoru Miyauchi received his MD in 1999 from Nagoya Institute of Technology in Japan
And then he joined CHISSO Co Ltd as an engineer in fiber division His responsibility
was mainly RampD of synthetic fibers for industry In 2008 he started to study at Professor
Linhardt group as a visiting researcher from CHISSO
Trevor J Simmons earned his BS in Chemical Science from SUNY Stony Brook in 2004
and a PhD in Chemistry from Rensselaer Polytechnic Institute (RPI) in Troy NY in 2008
under the guidance of Dr Pulickel M Ajayan and Dr Robert J Linhardt He has primarily
worked in academics but also has recently worked as a nanotechnology consultant with a
cellulose-based energy storage company Research interests focus on carbon nanomaterials
chemistry in nanotechnology cellulosic materials energy storage and engineering novel
applications in these areas but he maintains a wide-range of interests in chemistry physics
biotechnology and materials science He has published several peer-reviewed papers in the
area of carbon nanotubes and cellulosic materials He currently works as a postdoctoral
investigator for the Coordinacion para la Investigacion y Aplicacion de la Ciencia y la
Tecnologıa (CIACyT) which is part of the Universidad Autonoma de San Luis Potosı
(UASLP) in San Luis Potosı Mexico He also conducts investigations as a visiting scholar at RPI with Dr Linhardt and
works as a consultant for the Paper Battery Company of Troy NY
Jonathan S Dordick received his BA degree in Biochemistry and Chemistry from
Brandeis University and his PhD in Biochemical Engineering from the Massachusetts Insti-
tute of Technology He has held chemical engineering faculty appointments at the University
of Iowa (1987ndash1998) where he also served as the Associate Director of the Center for Bio-
catalysis and Bioprocessing and Rensselaer Polytechnic Institute (1998ndashpresent) where he
is the Howard P Isermann Professor of Chemical and Biological Engineering and Professor
of Biology and Director of the Center for Biotechnology and Interdisciplinary Studies
Professor Dordick has received numerous awards including the American Chemical Soci-
etyrsquos Marvin Johnson and Elmer Gaden Awards the International Enzyme Engineering
Award the Iowa Section Award of the ACS and an NSF Presidential Young Investigator
Award in 1989 and he has been elected as a Fellow of the American Association for the
Advancement of Science and the American Institute of Medical and Biological Engineers
have a corendashsheath composition which contain cores and
sheaths made of different materials A flexible polymer
usually resides in the sheath while another polymer with
a unique property such as low solubility or conductiv-
ity (eg poly(34-ethylenedioxythiophene) (PEDOT)) is
located in the core10 Nanomaterials such as nanoparticles
5508 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Robert J Linhardt received his PhD degree from the Johns Hopkins University (1979)
and was a postdoctoral student with Professor Robert Langer at the Massachusetts Institute
of Technology (1979ndash1982) and served on the faculty of University of Iowa from 1982ndash
2003 He is currently the Ann and John H Broadbent Jrrsquo59 Senior Constellation Professor
of Biocatalysis and Metabolic Engineering at Rensselaer Polytechnic Institute holding joint
appointments in the Departments of Chemistry and Chemical Biology Biology and Chemi-
cal and Biological Engineering His honors include the American Chemical Society Horace
S Isbell and Claude S Hudson Awards and the AACP Volwiler Research Achievement
Award His research focuses on glycobiology glycochemistry and glycoengineering Since
his arrival at Rensselaer Dr Linhardt has been actively involved in the emerging field of
nano-biotechnology focused on developing an artificial Golgi and paper-based energy stor-
age devices Professor Linhardt has published nearly 500 peer-reviewed manuscripts and
holds over 30 patents
or nanotubes can also be encapsulated in the core struc-
ture When p and n semiconductor materials are fab-
ricated into such a coaxial structure the contact area
between pndashn heterojunctions are maximized by reduc-
ing fiber diameter which for example can be used to
improve solar cell performance11 Electrospinning of abun-
dant and renewable natural biopolymers such as cellu-
lose and chitin is becoming an increasingly active area of
research However there are very few suitable solvents for
such biopolymers which significantly limits their use in
electrospinning Room temperature ionic liquids (RTILs)
nonvolatile solvents with high thermal stability that can
dissolve both highly polar and nonpolar polymers12ndash15
offer a potential solution to the poor solubility associated
with polysaccharides such as cellulose that limits their
application to electrospinning Unlike spinning a polymer
solution in volatile solvents which quickly evaporate in
the low pressure surrounding the fiber jet non-volatile
RTILs must be removed using a miscible co-solvent coag-
ulation bath to solidify polymer fiber
12 Electrospinning in Energy Applications
The search for alternative and stable sources of energy
is a growing and vital concern Although ldquocleanrdquo power
sources like nuclear wind solar and fuel cells have
been around for many years significant hurdles remain in
exploiting these sources on large enough scale to solve
the emerging energy crisis As a consequence increased
attention has focused on applying electrospinning in the
preparation of porous fiber mats as electronic components
including electrodes and separators and devices such as
batteries and supercapacitors (Fig 1(b)) Electrospun fiber
mats are capable of improving battery power increasing
energy density of capacitors and fuel cell and solar cell
efficiency Poly(olefin) microporous membranes are widely
used as commercial separators for Li-ion batteries16 and
although these conventional separators have a number of
suitable properties ie chemical stability tunable thick-
ness and mechanical strength17 their low porosity and
poor wettability resulting from the large polarity differ-
ence between non-polar poly(olefin) separator and highly
polar liquid electrolyte lead to increased cell resistance
limiting the performance of Li-ion batteries18 Electro-
spun fiber mats have extremely high specific areas as a
result of their high porosity making them a good can-
didate for battery membranes By introducing a polar
block to diblock polymers such as sulfonated styrene
Corendashshell nanofibers
Syringe pump
Core solution
Shell solutionHigh voltage
Electrically groundedcollecting plate
Core
Fiber structureS
hell
She
ll
(a)
(b)
Fig 1 (a) Schematic of electrospinning apparatus In spinning of corendash
shell (sheath) fibers both pumps are used with a coaxial needle assembly
in the spinneret In single solution electrospinning only a single pump
containing core solution is spun through a single needle (b) Performance
characteristics of powerenergy storage devices Reproduced with per-
mission from [76] R Kotz and M Carlen Electrochim Acta 45 2483
(2000) copy 2000 Elsevier
J Nanosci Nanotechnol 10 5507ndash5519 2010 5509
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
the resulting electrospun fiber membranes afford separa-
tors with excellent affinity for liquid electrolytes increas-
ing ionic conductivity and battery performance The high
internal surface area large pore volume and long fiber
length of conducting electrospun membranes also make
them suitable as electrodes in Li-ion batteries Transi-
tion metal oxide (particles or nanoparticles) loaded onto
carbon nanofibers (CNF) facilitate more complete access
of Li ions to the inner sites of anodes decreasing Li-
ion diffusion distance and significantly increasing the rate
of electron transport Nano-structured LiCoO2 electrodes
afford a higher initial discharge capacity of sim140 (mAh)g
than conventional powder-based and film-based electrodes
However due to surface reactions of electrodes a large
loss of electrode capacity is observed during the chargendash
discharge process By electrospinning inorganic coaxial
fibers having a highly crystalline LiCoO2 core and a
low crystalline MgO shell electrodes may be obtained in
which LiCoO2 cannot directly contact electrolyte These
electrodes exhibit improved electrochemical properties
including excellent reversibility small impedance growth
and better cyclability9
The many applications and unique features of
electrospinning has been reviewed in a number
of publications719ndash21 This review provides an overview
of the application of electrospinning to the preparation of
electronic components and devices The text presents a
brief introduction of the mechanisms and methodology for
electrospinning and the application of electrospinning to
the preparation of separators electrodes nanowires super-
capacitors and actuators Finally the challenges for future
developments in electrospinning are briefly discussed
13 Electrospinning Methods and Principles
A typical electrospinning apparatus consists of a syringe
syringe pump spinneret collector and high voltage power
supply In single solution spinning a solution of solute in
volatile solvent is pumped through a nozzle Two solu-
tions are used in coaxial spinning where a core solution
is pumped through a needle at the same time a sheath
solution is pumped through the space between the noz-
zle and needle (Fig 1(a)) A potential of 10ndash50 kV is
applied between the spinneret where the spinning solu-
tion is located and the collector plate In electrospinning
with non-volatile solvents a co-solvent coagulation bath
is interposed between the spinneret and collector plate
The spinneret and collector are electrically conducting
and separated at an optimum distance When high volt-
age is applied the solution becomes highly charged and
as a result the solution droplet at the tip of the needle
will experience two major types of electrostatic forces
the repulsion between the surface charges and Coulombic
force exerted by the external electric field When a criti-
cal voltage is reached these electrostatic forces cause the
pendant droplet of polymer fluid to deform into a conical
structure called a Taylor cone Once the applied voltage
surpasses the critical value at which repulsive electrostatic
forces overcome the surface tension of the pendant droplet
a fiber jet is ejected from the apex of the Taylor cone and
accelerated towards the grounded collector or co-solvent
bath The fiber jet undergoes a whipping motion and
continuously elongates under this electrostatic repulsion
Instability can occur if the applied voltage is below the
critical value causing the jet to break up into droplets or
form a spray Such phenomenon is called Rayleigh insta-
bility Therefore the formation of nanofibers is determined
by many operating parameters such as applied voltage
solution concentration viscosity surface tension conduc-
tivity and flow rate The structure of the resulting fiber
can be tuned by carefully modifying these parameters
2 APPLICATIONS OF ELECTROSPINNINGPREPARING ELECTRICAL COMPONENTSAND DEVICES
21 Electrospun Insulators Separatorsand Electrolytes
Electrospun polymers such as polyvinylidenedifluoride
(PVDF) and polyacrylonitrile (PAN) and their deriva-
tives can be used as nanofiber mats in separators of
Li-ion batteries providing a nanoporous structure lead-
ing to increased ionic conductivity of a membrane soaked
with liquid electrolyte Aligned electrospun PVDF fibrous
membranes can enhance the tensile strength and mod-
ulus of membranes by improving interfiber compaction
under hot pressing Such electrospun membranes may have
important applications as battery separators
Uniform electrospun PVDF membrane thickness and
fiber diameter can be obtained by using high poly-
mer concentrations and electrospinning at high volt-
age This improves mechanical strength and provides the
PVDF separator with charge and discharge capacities
that exceed commercial polypropylene separators while
resulting in little capacity loss (Fig 2)2223 However
the high crystallinity of PVDF results in low conduc-
tivity The use of diblock polymers reduce crystallinity
while retaining a high dielectric constant which offers
one approach for improving resulting battery performance
Electric double-layer (EDL) capacitors (also known
as ultra or supercapacitors) prepared with electrospun
nonwoven poly(vinylidene fluoride-hexafluoropropylene)
(PVDF-PHFP) membrane separators and 1-ethyl-3-methyl
immidazolium tetrafluoroborate (emim[BF4]) RTIL elec-
trolyte exhibit excellent specific capacity and cycling
efficiency24
Electrospun PAN nonwoven fibers show higher porosi-
ties with lower Gurley values (high air permeability) and
increased wettabilities compared to conventional separa-
tors Furthermore cells with separators of PAN nonwovens
5510 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
(a)
(b)
Fig 2 Cyclic voltammograms for the cells with separator
(a) CelgardTM 2400 (polypropylene) and (b) EPM884 (PVDF) at sweep
rate 01 mVsminus1 Reproduced with permission from [23] K Gao et al
Mater Sci Eng B 131 100 (2006) copy 2006 Elsevier
show enhanced cycle lifeperformance higher rate capa-
bilities and smaller diffusion resistance than cells with
conventional separators (Fig 3)2526
Polymer electrolytes have a number of advantages over
liquid electrolytes such as limited internal shorting and
low electrolyte leakage One of most widely used methods
to prepare polymer electrolytes is the immobilization of
1 M lithium hexafluorophosphate (LiPF6 within ethylene
carbonate (EC)dimethyl carbonate (DMC) in electrospun
fiber membranes27 An increased interest in improving the
performance of Li-ion polymer batteries has resulted from
the rapid expansion in the industrial demand for these
batteries Improved performance has relied on gel poly-
mer electrolytes (GPEs) such as those based on electro-
spun PVDF-graft-poly-tert-butylacrylate (g-tBA) nanofiber
(a)
(b)
Fig 3 (a) Results of discharge capacity tests for the cells with the Cel-
gard membrane and the PAN nonwovens Reproduced with permission
from [25] T H Cho et al J Power Sources 181 155 (2008) copy 2008
Elsevier (b) Results of rate capability test for the cells with PE PP PAN
No 1 and PAN No 2 separators Reproduced with permission from [26]
T H Cho et al Electrochem Solid State Lett 10 A159 (2007) copy 2007
The Electrochemical Society
membranes These GPEs show improved ionic conductiv-
ity electrochemical stability lower interfacial resistance
and improved cycle performance compared to neat PVDF
nanofiber membranes resulting from the reduced crys-
tallinity of tBA-grafted PVDF28
Electrospun PVDF-PHFPsilica composite nanofiber-
based polymer electrolytes were comparatively better than
those prepared through the direct addition of silica27 Dye-
sensitized solar cell (DSSC) devices also use polymer elec-
trolytes based on electrospun PVDF-PHFP nanofibers and
show power conversion efficiency greater than 529
22 Electrospun Electrodes
Electrospinning is an excellent method for the fabrica-
tion of inorganic fibers within a templated polymer For
J Nanosci Nanotechnol 10 5507ndash5519 2010 5511
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
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19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
have been electrospun into fiber mats and membranes
New technologies have been introduced for electrospin-
ning such as double needle electrospinning (Fig 1(a))
which can fabricate fibers from two different compo-
nents simultaneously such as polymers or polymers and
solids combinations or solndashgels9 The resulting fibers
Jianjun Miao received his BS degree in Chemical Engineering from East China University
of Science and Technology (ECUST) in 2001 and PhD degree in Chemical Engineering
from University of Connecticut in 2009 He joined Professor Linhardtrsquos group at Rensselaer
Polytechnic Institute as a postdoctoral fellow in 2009 His research interests include electro-
spinning nanostructured materials bionanomaterials and nanostructure-based devices He
has published nine peer-reviewed papers in the area of materials chemistry
Minoru Miyauchi received his MD in 1999 from Nagoya Institute of Technology in Japan
And then he joined CHISSO Co Ltd as an engineer in fiber division His responsibility
was mainly RampD of synthetic fibers for industry In 2008 he started to study at Professor
Linhardt group as a visiting researcher from CHISSO
Trevor J Simmons earned his BS in Chemical Science from SUNY Stony Brook in 2004
and a PhD in Chemistry from Rensselaer Polytechnic Institute (RPI) in Troy NY in 2008
under the guidance of Dr Pulickel M Ajayan and Dr Robert J Linhardt He has primarily
worked in academics but also has recently worked as a nanotechnology consultant with a
cellulose-based energy storage company Research interests focus on carbon nanomaterials
chemistry in nanotechnology cellulosic materials energy storage and engineering novel
applications in these areas but he maintains a wide-range of interests in chemistry physics
biotechnology and materials science He has published several peer-reviewed papers in the
area of carbon nanotubes and cellulosic materials He currently works as a postdoctoral
investigator for the Coordinacion para la Investigacion y Aplicacion de la Ciencia y la
Tecnologıa (CIACyT) which is part of the Universidad Autonoma de San Luis Potosı
(UASLP) in San Luis Potosı Mexico He also conducts investigations as a visiting scholar at RPI with Dr Linhardt and
works as a consultant for the Paper Battery Company of Troy NY
Jonathan S Dordick received his BA degree in Biochemistry and Chemistry from
Brandeis University and his PhD in Biochemical Engineering from the Massachusetts Insti-
tute of Technology He has held chemical engineering faculty appointments at the University
of Iowa (1987ndash1998) where he also served as the Associate Director of the Center for Bio-
catalysis and Bioprocessing and Rensselaer Polytechnic Institute (1998ndashpresent) where he
is the Howard P Isermann Professor of Chemical and Biological Engineering and Professor
of Biology and Director of the Center for Biotechnology and Interdisciplinary Studies
Professor Dordick has received numerous awards including the American Chemical Soci-
etyrsquos Marvin Johnson and Elmer Gaden Awards the International Enzyme Engineering
Award the Iowa Section Award of the ACS and an NSF Presidential Young Investigator
Award in 1989 and he has been elected as a Fellow of the American Association for the
Advancement of Science and the American Institute of Medical and Biological Engineers
have a corendashsheath composition which contain cores and
sheaths made of different materials A flexible polymer
usually resides in the sheath while another polymer with
a unique property such as low solubility or conductiv-
ity (eg poly(34-ethylenedioxythiophene) (PEDOT)) is
located in the core10 Nanomaterials such as nanoparticles
5508 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Robert J Linhardt received his PhD degree from the Johns Hopkins University (1979)
and was a postdoctoral student with Professor Robert Langer at the Massachusetts Institute
of Technology (1979ndash1982) and served on the faculty of University of Iowa from 1982ndash
2003 He is currently the Ann and John H Broadbent Jrrsquo59 Senior Constellation Professor
of Biocatalysis and Metabolic Engineering at Rensselaer Polytechnic Institute holding joint
appointments in the Departments of Chemistry and Chemical Biology Biology and Chemi-
cal and Biological Engineering His honors include the American Chemical Society Horace
S Isbell and Claude S Hudson Awards and the AACP Volwiler Research Achievement
Award His research focuses on glycobiology glycochemistry and glycoengineering Since
his arrival at Rensselaer Dr Linhardt has been actively involved in the emerging field of
nano-biotechnology focused on developing an artificial Golgi and paper-based energy stor-
age devices Professor Linhardt has published nearly 500 peer-reviewed manuscripts and
holds over 30 patents
or nanotubes can also be encapsulated in the core struc-
ture When p and n semiconductor materials are fab-
ricated into such a coaxial structure the contact area
between pndashn heterojunctions are maximized by reduc-
ing fiber diameter which for example can be used to
improve solar cell performance11 Electrospinning of abun-
dant and renewable natural biopolymers such as cellu-
lose and chitin is becoming an increasingly active area of
research However there are very few suitable solvents for
such biopolymers which significantly limits their use in
electrospinning Room temperature ionic liquids (RTILs)
nonvolatile solvents with high thermal stability that can
dissolve both highly polar and nonpolar polymers12ndash15
offer a potential solution to the poor solubility associated
with polysaccharides such as cellulose that limits their
application to electrospinning Unlike spinning a polymer
solution in volatile solvents which quickly evaporate in
the low pressure surrounding the fiber jet non-volatile
RTILs must be removed using a miscible co-solvent coag-
ulation bath to solidify polymer fiber
12 Electrospinning in Energy Applications
The search for alternative and stable sources of energy
is a growing and vital concern Although ldquocleanrdquo power
sources like nuclear wind solar and fuel cells have
been around for many years significant hurdles remain in
exploiting these sources on large enough scale to solve
the emerging energy crisis As a consequence increased
attention has focused on applying electrospinning in the
preparation of porous fiber mats as electronic components
including electrodes and separators and devices such as
batteries and supercapacitors (Fig 1(b)) Electrospun fiber
mats are capable of improving battery power increasing
energy density of capacitors and fuel cell and solar cell
efficiency Poly(olefin) microporous membranes are widely
used as commercial separators for Li-ion batteries16 and
although these conventional separators have a number of
suitable properties ie chemical stability tunable thick-
ness and mechanical strength17 their low porosity and
poor wettability resulting from the large polarity differ-
ence between non-polar poly(olefin) separator and highly
polar liquid electrolyte lead to increased cell resistance
limiting the performance of Li-ion batteries18 Electro-
spun fiber mats have extremely high specific areas as a
result of their high porosity making them a good can-
didate for battery membranes By introducing a polar
block to diblock polymers such as sulfonated styrene
Corendashshell nanofibers
Syringe pump
Core solution
Shell solutionHigh voltage
Electrically groundedcollecting plate
Core
Fiber structureS
hell
She
ll
(a)
(b)
Fig 1 (a) Schematic of electrospinning apparatus In spinning of corendash
shell (sheath) fibers both pumps are used with a coaxial needle assembly
in the spinneret In single solution electrospinning only a single pump
containing core solution is spun through a single needle (b) Performance
characteristics of powerenergy storage devices Reproduced with per-
mission from [76] R Kotz and M Carlen Electrochim Acta 45 2483
(2000) copy 2000 Elsevier
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
the resulting electrospun fiber membranes afford separa-
tors with excellent affinity for liquid electrolytes increas-
ing ionic conductivity and battery performance The high
internal surface area large pore volume and long fiber
length of conducting electrospun membranes also make
them suitable as electrodes in Li-ion batteries Transi-
tion metal oxide (particles or nanoparticles) loaded onto
carbon nanofibers (CNF) facilitate more complete access
of Li ions to the inner sites of anodes decreasing Li-
ion diffusion distance and significantly increasing the rate
of electron transport Nano-structured LiCoO2 electrodes
afford a higher initial discharge capacity of sim140 (mAh)g
than conventional powder-based and film-based electrodes
However due to surface reactions of electrodes a large
loss of electrode capacity is observed during the chargendash
discharge process By electrospinning inorganic coaxial
fibers having a highly crystalline LiCoO2 core and a
low crystalline MgO shell electrodes may be obtained in
which LiCoO2 cannot directly contact electrolyte These
electrodes exhibit improved electrochemical properties
including excellent reversibility small impedance growth
and better cyclability9
The many applications and unique features of
electrospinning has been reviewed in a number
of publications719ndash21 This review provides an overview
of the application of electrospinning to the preparation of
electronic components and devices The text presents a
brief introduction of the mechanisms and methodology for
electrospinning and the application of electrospinning to
the preparation of separators electrodes nanowires super-
capacitors and actuators Finally the challenges for future
developments in electrospinning are briefly discussed
13 Electrospinning Methods and Principles
A typical electrospinning apparatus consists of a syringe
syringe pump spinneret collector and high voltage power
supply In single solution spinning a solution of solute in
volatile solvent is pumped through a nozzle Two solu-
tions are used in coaxial spinning where a core solution
is pumped through a needle at the same time a sheath
solution is pumped through the space between the noz-
zle and needle (Fig 1(a)) A potential of 10ndash50 kV is
applied between the spinneret where the spinning solu-
tion is located and the collector plate In electrospinning
with non-volatile solvents a co-solvent coagulation bath
is interposed between the spinneret and collector plate
The spinneret and collector are electrically conducting
and separated at an optimum distance When high volt-
age is applied the solution becomes highly charged and
as a result the solution droplet at the tip of the needle
will experience two major types of electrostatic forces
the repulsion between the surface charges and Coulombic
force exerted by the external electric field When a criti-
cal voltage is reached these electrostatic forces cause the
pendant droplet of polymer fluid to deform into a conical
structure called a Taylor cone Once the applied voltage
surpasses the critical value at which repulsive electrostatic
forces overcome the surface tension of the pendant droplet
a fiber jet is ejected from the apex of the Taylor cone and
accelerated towards the grounded collector or co-solvent
bath The fiber jet undergoes a whipping motion and
continuously elongates under this electrostatic repulsion
Instability can occur if the applied voltage is below the
critical value causing the jet to break up into droplets or
form a spray Such phenomenon is called Rayleigh insta-
bility Therefore the formation of nanofibers is determined
by many operating parameters such as applied voltage
solution concentration viscosity surface tension conduc-
tivity and flow rate The structure of the resulting fiber
can be tuned by carefully modifying these parameters
2 APPLICATIONS OF ELECTROSPINNINGPREPARING ELECTRICAL COMPONENTSAND DEVICES
21 Electrospun Insulators Separatorsand Electrolytes
Electrospun polymers such as polyvinylidenedifluoride
(PVDF) and polyacrylonitrile (PAN) and their deriva-
tives can be used as nanofiber mats in separators of
Li-ion batteries providing a nanoporous structure lead-
ing to increased ionic conductivity of a membrane soaked
with liquid electrolyte Aligned electrospun PVDF fibrous
membranes can enhance the tensile strength and mod-
ulus of membranes by improving interfiber compaction
under hot pressing Such electrospun membranes may have
important applications as battery separators
Uniform electrospun PVDF membrane thickness and
fiber diameter can be obtained by using high poly-
mer concentrations and electrospinning at high volt-
age This improves mechanical strength and provides the
PVDF separator with charge and discharge capacities
that exceed commercial polypropylene separators while
resulting in little capacity loss (Fig 2)2223 However
the high crystallinity of PVDF results in low conduc-
tivity The use of diblock polymers reduce crystallinity
while retaining a high dielectric constant which offers
one approach for improving resulting battery performance
Electric double-layer (EDL) capacitors (also known
as ultra or supercapacitors) prepared with electrospun
nonwoven poly(vinylidene fluoride-hexafluoropropylene)
(PVDF-PHFP) membrane separators and 1-ethyl-3-methyl
immidazolium tetrafluoroborate (emim[BF4]) RTIL elec-
trolyte exhibit excellent specific capacity and cycling
efficiency24
Electrospun PAN nonwoven fibers show higher porosi-
ties with lower Gurley values (high air permeability) and
increased wettabilities compared to conventional separa-
tors Furthermore cells with separators of PAN nonwovens
5510 J Nanosci Nanotechnol 10 5507ndash5519 2010
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REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
(a)
(b)
Fig 2 Cyclic voltammograms for the cells with separator
(a) CelgardTM 2400 (polypropylene) and (b) EPM884 (PVDF) at sweep
rate 01 mVsminus1 Reproduced with permission from [23] K Gao et al
Mater Sci Eng B 131 100 (2006) copy 2006 Elsevier
show enhanced cycle lifeperformance higher rate capa-
bilities and smaller diffusion resistance than cells with
conventional separators (Fig 3)2526
Polymer electrolytes have a number of advantages over
liquid electrolytes such as limited internal shorting and
low electrolyte leakage One of most widely used methods
to prepare polymer electrolytes is the immobilization of
1 M lithium hexafluorophosphate (LiPF6 within ethylene
carbonate (EC)dimethyl carbonate (DMC) in electrospun
fiber membranes27 An increased interest in improving the
performance of Li-ion polymer batteries has resulted from
the rapid expansion in the industrial demand for these
batteries Improved performance has relied on gel poly-
mer electrolytes (GPEs) such as those based on electro-
spun PVDF-graft-poly-tert-butylacrylate (g-tBA) nanofiber
(a)
(b)
Fig 3 (a) Results of discharge capacity tests for the cells with the Cel-
gard membrane and the PAN nonwovens Reproduced with permission
from [25] T H Cho et al J Power Sources 181 155 (2008) copy 2008
Elsevier (b) Results of rate capability test for the cells with PE PP PAN
No 1 and PAN No 2 separators Reproduced with permission from [26]
T H Cho et al Electrochem Solid State Lett 10 A159 (2007) copy 2007
The Electrochemical Society
membranes These GPEs show improved ionic conductiv-
ity electrochemical stability lower interfacial resistance
and improved cycle performance compared to neat PVDF
nanofiber membranes resulting from the reduced crys-
tallinity of tBA-grafted PVDF28
Electrospun PVDF-PHFPsilica composite nanofiber-
based polymer electrolytes were comparatively better than
those prepared through the direct addition of silica27 Dye-
sensitized solar cell (DSSC) devices also use polymer elec-
trolytes based on electrospun PVDF-PHFP nanofibers and
show power conversion efficiency greater than 529
22 Electrospun Electrodes
Electrospinning is an excellent method for the fabrica-
tion of inorganic fibers within a templated polymer For
J Nanosci Nanotechnol 10 5507ndash5519 2010 5511
Delivered by Ingenta toRensselaer Polytechnic Institute
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
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Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Robert J Linhardt received his PhD degree from the Johns Hopkins University (1979)
and was a postdoctoral student with Professor Robert Langer at the Massachusetts Institute
of Technology (1979ndash1982) and served on the faculty of University of Iowa from 1982ndash
2003 He is currently the Ann and John H Broadbent Jrrsquo59 Senior Constellation Professor
of Biocatalysis and Metabolic Engineering at Rensselaer Polytechnic Institute holding joint
appointments in the Departments of Chemistry and Chemical Biology Biology and Chemi-
cal and Biological Engineering His honors include the American Chemical Society Horace
S Isbell and Claude S Hudson Awards and the AACP Volwiler Research Achievement
Award His research focuses on glycobiology glycochemistry and glycoengineering Since
his arrival at Rensselaer Dr Linhardt has been actively involved in the emerging field of
nano-biotechnology focused on developing an artificial Golgi and paper-based energy stor-
age devices Professor Linhardt has published nearly 500 peer-reviewed manuscripts and
holds over 30 patents
or nanotubes can also be encapsulated in the core struc-
ture When p and n semiconductor materials are fab-
ricated into such a coaxial structure the contact area
between pndashn heterojunctions are maximized by reduc-
ing fiber diameter which for example can be used to
improve solar cell performance11 Electrospinning of abun-
dant and renewable natural biopolymers such as cellu-
lose and chitin is becoming an increasingly active area of
research However there are very few suitable solvents for
such biopolymers which significantly limits their use in
electrospinning Room temperature ionic liquids (RTILs)
nonvolatile solvents with high thermal stability that can
dissolve both highly polar and nonpolar polymers12ndash15
offer a potential solution to the poor solubility associated
with polysaccharides such as cellulose that limits their
application to electrospinning Unlike spinning a polymer
solution in volatile solvents which quickly evaporate in
the low pressure surrounding the fiber jet non-volatile
RTILs must be removed using a miscible co-solvent coag-
ulation bath to solidify polymer fiber
12 Electrospinning in Energy Applications
The search for alternative and stable sources of energy
is a growing and vital concern Although ldquocleanrdquo power
sources like nuclear wind solar and fuel cells have
been around for many years significant hurdles remain in
exploiting these sources on large enough scale to solve
the emerging energy crisis As a consequence increased
attention has focused on applying electrospinning in the
preparation of porous fiber mats as electronic components
including electrodes and separators and devices such as
batteries and supercapacitors (Fig 1(b)) Electrospun fiber
mats are capable of improving battery power increasing
energy density of capacitors and fuel cell and solar cell
efficiency Poly(olefin) microporous membranes are widely
used as commercial separators for Li-ion batteries16 and
although these conventional separators have a number of
suitable properties ie chemical stability tunable thick-
ness and mechanical strength17 their low porosity and
poor wettability resulting from the large polarity differ-
ence between non-polar poly(olefin) separator and highly
polar liquid electrolyte lead to increased cell resistance
limiting the performance of Li-ion batteries18 Electro-
spun fiber mats have extremely high specific areas as a
result of their high porosity making them a good can-
didate for battery membranes By introducing a polar
block to diblock polymers such as sulfonated styrene
Corendashshell nanofibers
Syringe pump
Core solution
Shell solutionHigh voltage
Electrically groundedcollecting plate
Core
Fiber structureS
hell
She
ll
(a)
(b)
Fig 1 (a) Schematic of electrospinning apparatus In spinning of corendash
shell (sheath) fibers both pumps are used with a coaxial needle assembly
in the spinneret In single solution electrospinning only a single pump
containing core solution is spun through a single needle (b) Performance
characteristics of powerenergy storage devices Reproduced with per-
mission from [76] R Kotz and M Carlen Electrochim Acta 45 2483
(2000) copy 2000 Elsevier
J Nanosci Nanotechnol 10 5507ndash5519 2010 5509
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
the resulting electrospun fiber membranes afford separa-
tors with excellent affinity for liquid electrolytes increas-
ing ionic conductivity and battery performance The high
internal surface area large pore volume and long fiber
length of conducting electrospun membranes also make
them suitable as electrodes in Li-ion batteries Transi-
tion metal oxide (particles or nanoparticles) loaded onto
carbon nanofibers (CNF) facilitate more complete access
of Li ions to the inner sites of anodes decreasing Li-
ion diffusion distance and significantly increasing the rate
of electron transport Nano-structured LiCoO2 electrodes
afford a higher initial discharge capacity of sim140 (mAh)g
than conventional powder-based and film-based electrodes
However due to surface reactions of electrodes a large
loss of electrode capacity is observed during the chargendash
discharge process By electrospinning inorganic coaxial
fibers having a highly crystalline LiCoO2 core and a
low crystalline MgO shell electrodes may be obtained in
which LiCoO2 cannot directly contact electrolyte These
electrodes exhibit improved electrochemical properties
including excellent reversibility small impedance growth
and better cyclability9
The many applications and unique features of
electrospinning has been reviewed in a number
of publications719ndash21 This review provides an overview
of the application of electrospinning to the preparation of
electronic components and devices The text presents a
brief introduction of the mechanisms and methodology for
electrospinning and the application of electrospinning to
the preparation of separators electrodes nanowires super-
capacitors and actuators Finally the challenges for future
developments in electrospinning are briefly discussed
13 Electrospinning Methods and Principles
A typical electrospinning apparatus consists of a syringe
syringe pump spinneret collector and high voltage power
supply In single solution spinning a solution of solute in
volatile solvent is pumped through a nozzle Two solu-
tions are used in coaxial spinning where a core solution
is pumped through a needle at the same time a sheath
solution is pumped through the space between the noz-
zle and needle (Fig 1(a)) A potential of 10ndash50 kV is
applied between the spinneret where the spinning solu-
tion is located and the collector plate In electrospinning
with non-volatile solvents a co-solvent coagulation bath
is interposed between the spinneret and collector plate
The spinneret and collector are electrically conducting
and separated at an optimum distance When high volt-
age is applied the solution becomes highly charged and
as a result the solution droplet at the tip of the needle
will experience two major types of electrostatic forces
the repulsion between the surface charges and Coulombic
force exerted by the external electric field When a criti-
cal voltage is reached these electrostatic forces cause the
pendant droplet of polymer fluid to deform into a conical
structure called a Taylor cone Once the applied voltage
surpasses the critical value at which repulsive electrostatic
forces overcome the surface tension of the pendant droplet
a fiber jet is ejected from the apex of the Taylor cone and
accelerated towards the grounded collector or co-solvent
bath The fiber jet undergoes a whipping motion and
continuously elongates under this electrostatic repulsion
Instability can occur if the applied voltage is below the
critical value causing the jet to break up into droplets or
form a spray Such phenomenon is called Rayleigh insta-
bility Therefore the formation of nanofibers is determined
by many operating parameters such as applied voltage
solution concentration viscosity surface tension conduc-
tivity and flow rate The structure of the resulting fiber
can be tuned by carefully modifying these parameters
2 APPLICATIONS OF ELECTROSPINNINGPREPARING ELECTRICAL COMPONENTSAND DEVICES
21 Electrospun Insulators Separatorsand Electrolytes
Electrospun polymers such as polyvinylidenedifluoride
(PVDF) and polyacrylonitrile (PAN) and their deriva-
tives can be used as nanofiber mats in separators of
Li-ion batteries providing a nanoporous structure lead-
ing to increased ionic conductivity of a membrane soaked
with liquid electrolyte Aligned electrospun PVDF fibrous
membranes can enhance the tensile strength and mod-
ulus of membranes by improving interfiber compaction
under hot pressing Such electrospun membranes may have
important applications as battery separators
Uniform electrospun PVDF membrane thickness and
fiber diameter can be obtained by using high poly-
mer concentrations and electrospinning at high volt-
age This improves mechanical strength and provides the
PVDF separator with charge and discharge capacities
that exceed commercial polypropylene separators while
resulting in little capacity loss (Fig 2)2223 However
the high crystallinity of PVDF results in low conduc-
tivity The use of diblock polymers reduce crystallinity
while retaining a high dielectric constant which offers
one approach for improving resulting battery performance
Electric double-layer (EDL) capacitors (also known
as ultra or supercapacitors) prepared with electrospun
nonwoven poly(vinylidene fluoride-hexafluoropropylene)
(PVDF-PHFP) membrane separators and 1-ethyl-3-methyl
immidazolium tetrafluoroborate (emim[BF4]) RTIL elec-
trolyte exhibit excellent specific capacity and cycling
efficiency24
Electrospun PAN nonwoven fibers show higher porosi-
ties with lower Gurley values (high air permeability) and
increased wettabilities compared to conventional separa-
tors Furthermore cells with separators of PAN nonwovens
5510 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
(a)
(b)
Fig 2 Cyclic voltammograms for the cells with separator
(a) CelgardTM 2400 (polypropylene) and (b) EPM884 (PVDF) at sweep
rate 01 mVsminus1 Reproduced with permission from [23] K Gao et al
Mater Sci Eng B 131 100 (2006) copy 2006 Elsevier
show enhanced cycle lifeperformance higher rate capa-
bilities and smaller diffusion resistance than cells with
conventional separators (Fig 3)2526
Polymer electrolytes have a number of advantages over
liquid electrolytes such as limited internal shorting and
low electrolyte leakage One of most widely used methods
to prepare polymer electrolytes is the immobilization of
1 M lithium hexafluorophosphate (LiPF6 within ethylene
carbonate (EC)dimethyl carbonate (DMC) in electrospun
fiber membranes27 An increased interest in improving the
performance of Li-ion polymer batteries has resulted from
the rapid expansion in the industrial demand for these
batteries Improved performance has relied on gel poly-
mer electrolytes (GPEs) such as those based on electro-
spun PVDF-graft-poly-tert-butylacrylate (g-tBA) nanofiber
(a)
(b)
Fig 3 (a) Results of discharge capacity tests for the cells with the Cel-
gard membrane and the PAN nonwovens Reproduced with permission
from [25] T H Cho et al J Power Sources 181 155 (2008) copy 2008
Elsevier (b) Results of rate capability test for the cells with PE PP PAN
No 1 and PAN No 2 separators Reproduced with permission from [26]
T H Cho et al Electrochem Solid State Lett 10 A159 (2007) copy 2007
The Electrochemical Society
membranes These GPEs show improved ionic conductiv-
ity electrochemical stability lower interfacial resistance
and improved cycle performance compared to neat PVDF
nanofiber membranes resulting from the reduced crys-
tallinity of tBA-grafted PVDF28
Electrospun PVDF-PHFPsilica composite nanofiber-
based polymer electrolytes were comparatively better than
those prepared through the direct addition of silica27 Dye-
sensitized solar cell (DSSC) devices also use polymer elec-
trolytes based on electrospun PVDF-PHFP nanofibers and
show power conversion efficiency greater than 529
22 Electrospun Electrodes
Electrospinning is an excellent method for the fabrica-
tion of inorganic fibers within a templated polymer For
J Nanosci Nanotechnol 10 5507ndash5519 2010 5511
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IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
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19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
the resulting electrospun fiber membranes afford separa-
tors with excellent affinity for liquid electrolytes increas-
ing ionic conductivity and battery performance The high
internal surface area large pore volume and long fiber
length of conducting electrospun membranes also make
them suitable as electrodes in Li-ion batteries Transi-
tion metal oxide (particles or nanoparticles) loaded onto
carbon nanofibers (CNF) facilitate more complete access
of Li ions to the inner sites of anodes decreasing Li-
ion diffusion distance and significantly increasing the rate
of electron transport Nano-structured LiCoO2 electrodes
afford a higher initial discharge capacity of sim140 (mAh)g
than conventional powder-based and film-based electrodes
However due to surface reactions of electrodes a large
loss of electrode capacity is observed during the chargendash
discharge process By electrospinning inorganic coaxial
fibers having a highly crystalline LiCoO2 core and a
low crystalline MgO shell electrodes may be obtained in
which LiCoO2 cannot directly contact electrolyte These
electrodes exhibit improved electrochemical properties
including excellent reversibility small impedance growth
and better cyclability9
The many applications and unique features of
electrospinning has been reviewed in a number
of publications719ndash21 This review provides an overview
of the application of electrospinning to the preparation of
electronic components and devices The text presents a
brief introduction of the mechanisms and methodology for
electrospinning and the application of electrospinning to
the preparation of separators electrodes nanowires super-
capacitors and actuators Finally the challenges for future
developments in electrospinning are briefly discussed
13 Electrospinning Methods and Principles
A typical electrospinning apparatus consists of a syringe
syringe pump spinneret collector and high voltage power
supply In single solution spinning a solution of solute in
volatile solvent is pumped through a nozzle Two solu-
tions are used in coaxial spinning where a core solution
is pumped through a needle at the same time a sheath
solution is pumped through the space between the noz-
zle and needle (Fig 1(a)) A potential of 10ndash50 kV is
applied between the spinneret where the spinning solu-
tion is located and the collector plate In electrospinning
with non-volatile solvents a co-solvent coagulation bath
is interposed between the spinneret and collector plate
The spinneret and collector are electrically conducting
and separated at an optimum distance When high volt-
age is applied the solution becomes highly charged and
as a result the solution droplet at the tip of the needle
will experience two major types of electrostatic forces
the repulsion between the surface charges and Coulombic
force exerted by the external electric field When a criti-
cal voltage is reached these electrostatic forces cause the
pendant droplet of polymer fluid to deform into a conical
structure called a Taylor cone Once the applied voltage
surpasses the critical value at which repulsive electrostatic
forces overcome the surface tension of the pendant droplet
a fiber jet is ejected from the apex of the Taylor cone and
accelerated towards the grounded collector or co-solvent
bath The fiber jet undergoes a whipping motion and
continuously elongates under this electrostatic repulsion
Instability can occur if the applied voltage is below the
critical value causing the jet to break up into droplets or
form a spray Such phenomenon is called Rayleigh insta-
bility Therefore the formation of nanofibers is determined
by many operating parameters such as applied voltage
solution concentration viscosity surface tension conduc-
tivity and flow rate The structure of the resulting fiber
can be tuned by carefully modifying these parameters
2 APPLICATIONS OF ELECTROSPINNINGPREPARING ELECTRICAL COMPONENTSAND DEVICES
21 Electrospun Insulators Separatorsand Electrolytes
Electrospun polymers such as polyvinylidenedifluoride
(PVDF) and polyacrylonitrile (PAN) and their deriva-
tives can be used as nanofiber mats in separators of
Li-ion batteries providing a nanoporous structure lead-
ing to increased ionic conductivity of a membrane soaked
with liquid electrolyte Aligned electrospun PVDF fibrous
membranes can enhance the tensile strength and mod-
ulus of membranes by improving interfiber compaction
under hot pressing Such electrospun membranes may have
important applications as battery separators
Uniform electrospun PVDF membrane thickness and
fiber diameter can be obtained by using high poly-
mer concentrations and electrospinning at high volt-
age This improves mechanical strength and provides the
PVDF separator with charge and discharge capacities
that exceed commercial polypropylene separators while
resulting in little capacity loss (Fig 2)2223 However
the high crystallinity of PVDF results in low conduc-
tivity The use of diblock polymers reduce crystallinity
while retaining a high dielectric constant which offers
one approach for improving resulting battery performance
Electric double-layer (EDL) capacitors (also known
as ultra or supercapacitors) prepared with electrospun
nonwoven poly(vinylidene fluoride-hexafluoropropylene)
(PVDF-PHFP) membrane separators and 1-ethyl-3-methyl
immidazolium tetrafluoroborate (emim[BF4]) RTIL elec-
trolyte exhibit excellent specific capacity and cycling
efficiency24
Electrospun PAN nonwoven fibers show higher porosi-
ties with lower Gurley values (high air permeability) and
increased wettabilities compared to conventional separa-
tors Furthermore cells with separators of PAN nonwovens
5510 J Nanosci Nanotechnol 10 5507ndash5519 2010
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Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
(a)
(b)
Fig 2 Cyclic voltammograms for the cells with separator
(a) CelgardTM 2400 (polypropylene) and (b) EPM884 (PVDF) at sweep
rate 01 mVsminus1 Reproduced with permission from [23] K Gao et al
Mater Sci Eng B 131 100 (2006) copy 2006 Elsevier
show enhanced cycle lifeperformance higher rate capa-
bilities and smaller diffusion resistance than cells with
conventional separators (Fig 3)2526
Polymer electrolytes have a number of advantages over
liquid electrolytes such as limited internal shorting and
low electrolyte leakage One of most widely used methods
to prepare polymer electrolytes is the immobilization of
1 M lithium hexafluorophosphate (LiPF6 within ethylene
carbonate (EC)dimethyl carbonate (DMC) in electrospun
fiber membranes27 An increased interest in improving the
performance of Li-ion polymer batteries has resulted from
the rapid expansion in the industrial demand for these
batteries Improved performance has relied on gel poly-
mer electrolytes (GPEs) such as those based on electro-
spun PVDF-graft-poly-tert-butylacrylate (g-tBA) nanofiber
(a)
(b)
Fig 3 (a) Results of discharge capacity tests for the cells with the Cel-
gard membrane and the PAN nonwovens Reproduced with permission
from [25] T H Cho et al J Power Sources 181 155 (2008) copy 2008
Elsevier (b) Results of rate capability test for the cells with PE PP PAN
No 1 and PAN No 2 separators Reproduced with permission from [26]
T H Cho et al Electrochem Solid State Lett 10 A159 (2007) copy 2007
The Electrochemical Society
membranes These GPEs show improved ionic conductiv-
ity electrochemical stability lower interfacial resistance
and improved cycle performance compared to neat PVDF
nanofiber membranes resulting from the reduced crys-
tallinity of tBA-grafted PVDF28
Electrospun PVDF-PHFPsilica composite nanofiber-
based polymer electrolytes were comparatively better than
those prepared through the direct addition of silica27 Dye-
sensitized solar cell (DSSC) devices also use polymer elec-
trolytes based on electrospun PVDF-PHFP nanofibers and
show power conversion efficiency greater than 529
22 Electrospun Electrodes
Electrospinning is an excellent method for the fabrica-
tion of inorganic fibers within a templated polymer For
J Nanosci Nanotechnol 10 5507ndash5519 2010 5511
Delivered by Ingenta toRensselaer Polytechnic Institute
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
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REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
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+
+
ndashndash
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ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
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+
+
+
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+
+
+
++
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ndashndashndash
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ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
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REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
(a)
(b)
Fig 2 Cyclic voltammograms for the cells with separator
(a) CelgardTM 2400 (polypropylene) and (b) EPM884 (PVDF) at sweep
rate 01 mVsminus1 Reproduced with permission from [23] K Gao et al
Mater Sci Eng B 131 100 (2006) copy 2006 Elsevier
show enhanced cycle lifeperformance higher rate capa-
bilities and smaller diffusion resistance than cells with
conventional separators (Fig 3)2526
Polymer electrolytes have a number of advantages over
liquid electrolytes such as limited internal shorting and
low electrolyte leakage One of most widely used methods
to prepare polymer electrolytes is the immobilization of
1 M lithium hexafluorophosphate (LiPF6 within ethylene
carbonate (EC)dimethyl carbonate (DMC) in electrospun
fiber membranes27 An increased interest in improving the
performance of Li-ion polymer batteries has resulted from
the rapid expansion in the industrial demand for these
batteries Improved performance has relied on gel poly-
mer electrolytes (GPEs) such as those based on electro-
spun PVDF-graft-poly-tert-butylacrylate (g-tBA) nanofiber
(a)
(b)
Fig 3 (a) Results of discharge capacity tests for the cells with the Cel-
gard membrane and the PAN nonwovens Reproduced with permission
from [25] T H Cho et al J Power Sources 181 155 (2008) copy 2008
Elsevier (b) Results of rate capability test for the cells with PE PP PAN
No 1 and PAN No 2 separators Reproduced with permission from [26]
T H Cho et al Electrochem Solid State Lett 10 A159 (2007) copy 2007
The Electrochemical Society
membranes These GPEs show improved ionic conductiv-
ity electrochemical stability lower interfacial resistance
and improved cycle performance compared to neat PVDF
nanofiber membranes resulting from the reduced crys-
tallinity of tBA-grafted PVDF28
Electrospun PVDF-PHFPsilica composite nanofiber-
based polymer electrolytes were comparatively better than
those prepared through the direct addition of silica27 Dye-
sensitized solar cell (DSSC) devices also use polymer elec-
trolytes based on electrospun PVDF-PHFP nanofibers and
show power conversion efficiency greater than 529
22 Electrospun Electrodes
Electrospinning is an excellent method for the fabrica-
tion of inorganic fibers within a templated polymer For
J Nanosci Nanotechnol 10 5507ndash5519 2010 5511
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
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19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
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21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
example electrospun LiCoO2 nanofibers have been used
as a cathode for Li-ion batteries resulting in improved
diffusion and increased migration of Li+ cation30 TiO2
nanofibers have been used in dye-sensitized solar cells31ndash34
These electrospun electrodes have a porous structure that
enhances the penetration of the viscous polymer gel elec-
trolyte Carbon nanofibers (CNFs) such as carbon nano-
tubes as well as conventional nano-scale carbon fibers have
also been fabricated from polymer solutions for use as
anode material for Li-ion batteries and as electrodes of
supercapacitors35ndash38
221 Electrodes of Li-ion Batteries
So far silicon (Si) has the highest theoretical capac-
ity sim4200 mAh gminus1 which is much greater than the
one of graphite and metal oxides3940 Therefore Si has
always been considered as an ideal anode material for
next-generation rechargeable Li-ion batteries with high-
capacity Dispersion of Si nanoparticles (Si NPs) in a
quasi-one-dimensional nanoporous CNF matrix is one of
approaches to make such high capacityconductivity elec-
trodes The CNF matrix holds Si NPs aggregation to
provide a continuous electron transport pathway as well
as large number of active sites for charge-transfer reac-
tions which eliminate the need for polymer binder Thus
CNFSi nanocomposites can offer a large accessible sur-
face area (Fig 4) therefore a high reversible capacity and
relatively good cycling performance at high current density
can be obtained35
Although transition metal oxides also exhibit promis-
ing electrochemical behavior they suffer from poor
cycling performance due to their agglomeration and
mechanical instabilities which are mainly caused by
large volume changes and aggregation during lithium
insertionextraction processes This results in increased dif-
fusion lengths and electrical disconnection from the cur-
rent collectors To solve these critical issues the porous
CNFs may be chosen as matrix to incorporate nano-sized
transition metal oxides since CNFs have very high inter-
nal surface areas large pore volumes and long fiber
lengths which facilitate more access of Li-ions to the inner
sites of anodes decrease Li-ion diffusion distance there-
fore significantly increase electron transport rate41 For
examples CarbonMnOx nanofiber anodes exhibit large
reversible capacity excellent capacity retention and good
rate capability in the absence of a binder polymer36
CNFFe3O4 composites also exhibit excellent electrochem-
ical performance with a high reversible capacity and excel-
lent rate capability38 High-purity CNFs electrospun from
PAN solutions exhibit a large accessible surface area
derived from the nanometer-sized fiber diameter high car-
bon purity (without binder) a relatively high electrical
conductivity high structural integrity thin web macromor-
phology large reversible capacity (sim450 mAh gminus1 and a
Fig 4 SEM images of PANPLLASi (1736) precursor nanofibers
(AndashC) and their corresponding porous CSi composite nanofibers (DndashF)
Reproduced with permission from [35] L W Ji and X W Zhang Elec-trochem Commun 11 1146 (2009) copy 2009 Elsevier
relatively linear voltage profile37 Nanostructured LiCoO2
fiber electrodes with faster diffusion of Li+ cations pre-
pared by electrospinning afford a higher initial discharge
capacity of 182 (mAh)g compared with that of con-
ventional powder and film electrodes (sim140 (mAh)g)30
Electrospun LiCoO2 nanofibers also have been used to
resolve instability induced by lithium intercalation and
de-intercalation and maintain the three-dimensional archi-
tecture of Li-ion batteries However a large loss of
capacity of fiber electrodes was still observed during
the chargendashdischarge process due to surface reactions
of electrodes To improve electrochemical stability sur-
face modification of the cathode material is necessary
and effective Coating of metal oxides on surface of
LiCoO2 particle or film as a shell material can prevent
these active electrode materials from directly contacting
the electrolyte and enhance the electrochemical stabil-
ity For example coating of lithium phosphorous oxyni-
tride onto the three-dimensional structure improved rate
capability and higher reversibility42 The fabrication of
inorganicndashinorganic coaxial fibers using electrospinning
technology is useful in this regard By co-electrospinning
a highly crystalline LiCoO2 core and a low crystallinity
MgO shell coaxial fibers were prepared exhibiting excel-
lent reversibility smaller impedance growth and better
5512 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
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REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
cyclability with improved electrochemical properties9 A
three-dimensional network architecture of anatase TiO2
and spinel Li4Ti5O12 has also been reported TiO2 nano-
fibers have poor cycle performance but Li4Ti5O12 exhibits
stable three-dimensional network architectures and shows
reversible electrochemical cycling Li4Ti5O12 may have
excellent potential for three-dimensional battery applica-
tions as a zero-strain insertion material43 A quasi-one-
dimensional array of Li1+V3O8 nanosheets prepared by
electrospinning combined with a solndashgel route gave higher
chargendashdischarge capacities and better cycle performance
compared to separated Li1+V3O8 nanosheets (Fig 5)44
Generally electrodes made from conducting polymers
are also composed of an insulating polymer or sul-
fonated polymer as binder The insulating polymer low-
ers the electrical conductivity of the resulting electrodes
however polymers used as both binder and dopant that
are sulfonated can increase electrical and electrochemical
properties4546 Electrospun polypyrrole (PPy)sulfonated
poly(styrene-ethylene-butylenes-styrene) (S-SEBS) fibers
can enhance electrochemical capacity due to the high dop-
ing level of S-SEBS and the ease of charge-transfer reac-
tions due to its high electrical conductivity47
Manganese-oxide (MnO) nanofibers prepared by elec-
trospinning PMMA gels with manganese salts shows
reversible electrochemical activity in lithium cells48 Nano-
sized nickel oxide (NiO) has also shown promise as
an anode material with excellent electrochemical per-
formance for lithium ion batteries49 Interestingly sin-
gle walled carbon nanotube-reinforced NiO nanofibers
have higher reversible capacity and lower capacity
loss than do conventional NiO electrodes50 Hollow
LiNi08Co01Mn01O2ndashMgO coaxial fibers have been pre-
pared with polyvinylpyrrolidone (PVP) and these fibers
show a high discharge capacity and excellent cycle
stability51 Co3O4 nanofibers have also shown high
Fig 5 The cycle life of the 1D arrays (a) and Li1+V3O8 nanosheets
(b) at a current density of 40 mA gminus1 Reproduced with permission from
[44] Y X Gu et al J Mater Chem 16 4361 (2006) copy 2006 Royal
Society of Chemistry
reversible capacity due to the high surface area of these
nanofibers52
222 Solar Cell and Fuel Cell Electrodes
High efficiency of light-to-energy conversion with dye-
sensitized solar cells (DSSCs) requires a high surface
area for the sensitized electrode53 DSSCs based on
nano-crystalline TiO2 have been intensively investigated
because of their low cost and reasonably high efficiency
Electrospun TiO2 fiber mats with large surface areas
enhance the light-harvesting capability of the adsorbed
dye TiO2 nanofibers are prepared by electrospinning of
a PVPTiO2 mixture The TiO2 nanofibers are then fab-
ricated into thick membrane electrodes to enhance elec-
tron percolation through interconnected nanofibers and to
improve the ability of absorption of low energy photons
thereby gradually increasing photocurrent and light har-
vesting efficiency as well as dye loading325455 The TiO2
electrodes used in DSSCs are electrospun directly onto
different substrates including a fluorine-doped tin oxide
(FTO) transparent conducting oxide substrate55 In this
manner the porous electrospun TiO2 electrode can be pen-
etrated efficiently with the viscous polymer gel electrolyte
due to its porous structure After treatment with aqueous
TiCl4 solution a short-circuit photocurrent was improved
and performance was enhanced by more than 3033 Plat-
inum nanoparticles supported on nanoporous carbon fiber
mats exhibit high activity and stability as electrocatalysts
in the oxidation of methanol in methanol fuel cells This
reduced the amount of platinum used and the associated
cost of this expensive catalyst56
23 Wires and Nanowires
The construction of nanomaterials particularly quasi-
one-dimensional nanowires mainly involves hydrothermal
methods solndashgel processes nanowire techniques vapor
growth template methods and electrospinning Wires and
nanowires fabricated by electrospinning potentially repre-
sent important building blocks for nanoscale chemical sen-
sors optoelectronics and photoluminescence since they
can potentially function as miniaturized devices as well as
electronic interconnects The large surface-to-volume ratio
and high electronndashhole conductivity along the quasi-1D
structure and high aspect ratio of nanowires makes them
ideal candidates for use as ultrasensitive chemical sensors
solar cells and fuel cell electrodes
231 Chemical Sensors
The pndashn type transition of nano-structured metal oxides
are important in sensing mechanisms involved in chem-
ical detection of charge-transfer interactions between a
sensor and the absorbed chemical species that modify
the electrical resistance of a sensor57 Size-related effects
J Nanosci Nanotechnol 10 5507ndash5519 2010 5513
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
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EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
of nanomaterials are also important with respect to free
charge carriers Electrospun SnO2 and MoO3 nanowires
show increased stability faster response time and higher
sensitivity than thin film structures of the same materials
in detecting H2S and NH3 respectively58 ZnO nanowires
prepared in an electrospinning process have been used to
detect ethanol vapor at concentrations as low as 10 ppm
at 220 C59 WO3 nanofibers behave as a semiconductor
when heated and their electrical resistance varies when
exposed to NO2 gas60 TiO2polyvinyl acetate composite
nanofibers also show exceptional sensitivity to NO2 when
electrospun onto Pt electrodes61
Tin-doped indium oxide electrospun nanowires show
a 107-fold enhancement in conductance compared to the
matrix without doping With such high conductance quasi-
one-dimensional nanowire FETs should be useful in build-
ing highly sensitive chemical and biological sensors of
reduced device dimensions62
232 Optoelectronics
Twisted electrospun ZnONiO nanofiber yarn (Fig 6)
act as pndashn heterojunctions exhibiting rectifying
currentndashvoltage (IndashV ) characteristics63 Highly aligned
multi-layers of TiO2 nanowire arrays with conjugated
polymers show more than 70 improvement com-
pared to non-woven TiO2 nanowire in power conversion
(a)
(d) (e) (1)
(2)
(b) (c)
Fig 6 Optical microscope image of (a) and (b) twisted pndashn junction NiOZnO nanofiber yarns annealed at 873 K and (c) tapered pndashn junction
NiOZnO nanofiber yarns annealed at 873 K (d) SEM image of NiO nanofiber yarn annealed at 873 K (e) Schematic diagram for the formation of (1)
tapered nanofiber pndashn junction yarn (2) twisted nanofiber pndashn junction yarn For both junctions the white yarn is an n-type ZnO while the gray yarn
is a p-type NiO Reproduced with permission from [63] A F Lotus et al J Appl Phys 106 014303 (2009) copy 2009 American Institute of Physics
due to enhanced charge collection and transport rate64
Aluminum-doped ZnO (AZO) is a low cost and non-
toxic transparent and conductive alternative to indium
tin oxide (ITO)65 Single electrospun nanowires of AZO
show a highly sensitive photoresponse under below-gap
light illumination compared to AZO films Well-oriented
quasi-one-dimensional CuO nanofibers are intrinsic p-typesemiconductors and when assembled in field-effect
transistors (FET) serve as a potentional building blocks
for low cost logic and switching circuits66 Necklace-like
PbTiO3 nanowires exhibit high surface photovoltage under
the action of an external electrical field which is useful
for optoelectric applications such as field effect controlled
devices6768
233 Photoluminescene
Hetero-structured electrospun Ag nanoparticle-loaded ZnO
nanowires exhibit enhanced UV photoresponse due
to enhanced separation of photogenerated electronndashhole
pairs69 Quasi-one-dimensional CaWO4 and CaWO4Tb3+
nanowires and nanotubes show strong blue and green
emissions upon excitation as a result of quantum con-
finement effects Tb3+ ions show characteristically strong
emissions due to an efficient energy transfer from
the WO2minus4 group to the Tb3+ ions70 Europium-doped
(YBO3Eu3+ nanowires show photoluminescence71 and
5514 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
Erbium-doped silicon and Germanium oxide nanofibers
are strongly emissive in the near infrared72 Aligned CdS
nanowires embedded in polymer nanofibers show linearly
polarized emissions73
234 Catalysts
Surface modified TiO2 anatase nanofibrous membranes
with incorporated Pt Pd and Ru nanoparticles show cat-
alytic properties that have been exploited in continuous
flow for Suzuki coupling reactions with short reaction
times and no need for separation74 Electrospun Pt and
PtRh nanowires show higher catalytic activities in a poly-
mer electrolyte membrane fuel cell anode than the con-
ventional Pt nanoparticle catalysts like carbon-supported
Pt or Pt black75 This improvement is due to the quasi-one-
dimensional pathway for electron transfer that dramatically
reduces the number of boundaries between the catalytic
nanoparticles
24 Supercapacitors
Supercapacitors (Fig 7) are well known as attractive
energy storage systems that exhibit high power den-
sity rapid chargingdischarging capacity and long cycle
life Potential applications range from small-scale mobile
devices to medium-scale electric vehicles to large-scale
power grid storage While the high power density of
supercapacitors compares favorably to batteries superca-
pacitors have a much lower energy density (Fig 1(b))76
Higher capacitance values and higher operating voltages
are critical to improve the energy density of supercapac-
itors The simplest way to obtain higher capacitance val-
ues of electrical double-layer capacitors is to increase the
ndash+
++ +
++
+
+
+
++
+
++
+
+
+
+
ndashndash
ndash
ndashndash
ndash
ndashndash
ndash
ndashndash
ndashndash
ndash
ndashndash
ndash
ndash
ndash ndash
ndash++
+
+
++
+
++
++
+
+
+
+
+
+
+
++
++
++
ndashndashndash
ndash
ndash
ndash
ndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
ndashndash
ndash
ndash
ndash
d = ~1 μm
Activated carbon ElectrodeSeparatorElectrolyte
Fig 7 Schematic diagram of electric double layer capacitor
(supercapacitor)
surface area of the supercapacitor electrodes and electro-
spun nanofibers can provide just such a property Activated
CNFs fabricated by electrospinning serve as excellent
candidates for supercapacitor electrodes Activated CNFs
have been fabricated from a variety of polymers77ndash79
which have high carbon yield including PAN poly(imide)
(PI) polybenzimidazol (PBI)8081 polyamic acid (PAA)
and isotropic pitch precursor (IPP) These polymer solu-
tions were electrospun into nanofibers and then stabilized
and carbonized at high temperature to obtain activated
CNFs Activated CNFs have high surface areas due to the
nanofiber morphology and porous structures on the fiber
surface82
Blending polymers and other additives with base poly-
mers has been studied to improve electrical conductivity
of activated CNFs Activated CNFs from PANcellulose
acetate composite solution showed increased conductiv-
ity due to the high oxygen content of cellulose acetate83
Activated carbon fibers from PANmulti-walled nanotubes
(MWNT)84 PANVO585 activated CNFMWNT coated
with polypyrrole86 and PANAg87 nanoparticle compos-
ites show improved conductivity due to the addition
of conductive materials andor coating with conductive
polymers Thinner fiber diameters were also examined
in PANMWNT and PANAg nanoparticle systems to
improve electrical conductivity and to enhance electro-
chemical performance Fiber diameter depends on several
electrospinning parameters such as solution concentration
applied voltage flow rate and solution conductivity The
diameter of an electrospun fiber decreases with increasing
the solution conductivity88 By adding conductive MWNT
or Ag nanoparticles into solution a greater tensile force
may be available in the presence of an electric field
Similar results were reported in systems of PANZinc
chloride and PANNickel nitrate8990 The higher surface
area resulting from thinner diameters produces improved
capacitance Physical activation of nanofibers is also pos-
sible using silica91 Silica embedded into nanofibers is
removed from carbon materials by immersing in hydroflu-
oric acid with the resulting carbon fiber showing a 30-fold
higher BET surface area which results in improved
capacitance
CNFs prepared from PANNickel acetate solution results
in a Ni-embedded carbon composite with more than three-
fold higher capacitance and improved electrochemical
stability92 Ni in CNFs works as an active species and
imparts a surface polarity to the fiber surface thus enhanc-
ing dipole affinity towards the anion and causing capaci-
tance to increase
The conductive polymer PEDOT was fabricated into
a fiber by electrospinning from ethylenedioxythiophene
(EDOT)PVP solution93 PVP is commonly added into
solutions as a matrix to improve electrospinnability After
electrospinning EDOT in the fiber is polymerized to
J Nanosci Nanotechnol 10 5507ndash5519 2010 5515
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
PEDOT by heating The resulting PEDOT nanofiber
showing high conductivity and high surface area can be
used as electrodes in flexible supercapacitors
Composites that enhance EDL capacitors and
pseudo-capacitors based on a Faradaic mechanism have
been studied Adding hydrous ruthenium oxide to carbon
generates the composite however by using this approach
it is difficult to obtain both the formation of mesoporous
and well-dispersed metal particles Ruthenium embed-
ded CNFs have been formed through electrospinning
of PANRuthenium acetylacetonate solution94 These
CNFs had both increased mesopore size and contained
well-dispersed Ruthenium particles The specific capaci-
tance increased from 140 Fg to 391 Fg because of the
combination of electrical double-layer capacitance and
pseudo-capacitance based on ruthenium oxidation
25 Actuators
Actuators can take electrical and other energy and con-
vert it into a mechanical motion However large strain
and quick response times still remain the most impor-
tant challenges in actuator design Large strain can be
obtained by enhancing mechanical properties and flexi-
ble electrospun fiber templates can be used to improve
strain This is because a large amount of electrolyte can
be localized in the porous structure of electrospun fiber
mats Good ion mobility is also possible in such fiber
mats thereby increasing the response speed of the actuator
and by simply reducing the fiber diameter in electrospin-
ning the response speed can be enhanced Unique thermal
response-type actuators can also be prepared by electro-
spinning A liquid crystalline main-chain polymer with a
photoactive moiety can also be electrospun into a highly
oriented fiber
251 Electrospun Fibers Coated withConductive Polymers
Among the many materials suitable for actuators con-
ducting polymers have received considerable attention as
promising candidates for actuator design owing to their
moderately high actuation strain at low operational volt-
ages below 1 V95ndash97 Despite being good candidates for
designing actuators the brittleness and poor elongation at
break98 of conducting polymers limit their active appli-
cability in devices Recent reports show the potential of
hydrogels being used as efficient candidates for actua-
tor applications owing to their stimuli responsive behav-
ior following a change in pH temperature or solvent
composition99100 A simple and versatile approach has
been described for the fabrication of flexible conducting
polymer actuators using hydrogel nanofibers as a tem-
plate An electrospun polyvinyl alcohol (PVA) nanofiber
mat containing a flexible conducting polymer actuator
prepared by in situ polymerization of aniline has been
reported101 The resulting structure has a large surface area
and high porosity that promotes facile diffusion of ions to
ensure efficient electrochemical reactions A higher strain
could also be obtained as a result of the enhanced mechan-
ical properties of this nanofiber mat (Fig 8)
(a)
(b)
(c)
Act
uatio
n st
rain
(
)
4
3
2
1
0
ndash1
4
3
2
1
0
ndash1
ndash2
ndash3
0
ndash02 00 02
Potential (V)
Cur
rent
(m
A)
04 06
Strip
Rolled
08
100
40 sec
10 sec
5 sec
4 sec
Scan rate (mVsec)
Res
pons
e sp
eed
(sec
ndash1)
200 300
020
015
010
005
000
400
Inter-layerspace
100 μm
Fig 8 (a) An FE-SEM image showing the rolled-up structure of
the PVAPANI hybrid mat The inset shows a cross-sectional image
of the rolled-up structure (b) A graph showing the variation in strain
and the subsequent response speed for the rolled up structure with
increasing scan rate (c) Cyclic voltammogram of the rolled-up structure
and the single strip measured at a scan rate of 5 mVs (Electrolyte =1 M methane sulfonic acid) Reproduced with permission from [101]
Y A Ismail et al Sens Actuator B-Chem 136 438 (2009) copy 2009
Elsevier
5516 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
252 Porous Electrospun Fiber Mats EnhanceIon Mobility
Aligned electrospun cellulose fibers have been obtained by
electrospinning using a wet-drawn stretching method102
Electrospun cellulose film-based electroactive paper
(EAPap) displayed a three-fold larger in-plane piezoelec-
tric charge constant than a similar spin cast cellulose
film The well-aligned cellulose fibers and well-developed
crystallinity of the electrospun cellulose film and the large
number of micro-cavities between layers improve the
performance of this actuator Nanofiber mats have been pre-
pared by electrospinning a sulfonated tetrafluoroethylene-
based fluoropolymerndashcopolymer (NafionTM103 When
these mats are saturated with ionic liquids they show
approximately three-fold improvement in ionic conductiv-
ity compared to conventional film-type membranes Also
these fabricated fiber mat-based transducers showed higher
strain speed of 134 per second which is 52 faster than
the film-based actuators (Fig 9)
Electrospun nanometer sized fibers should exhibit much
faster response times than commercially available micron
size fibers104 When submicron diameter PAN fibers were
prepared by electrospinning changing the pH caused
more than a 100 response improvement over conven-
tional fibers of diameters 10ndash50 m Thin polyacrylamide
(PAAM) gel fibers also show enhanced response times
253 Photo-Cross-Linkable Liquid CrystalMain-Chain Polymers
For mechanical actuators a response to external stimuli is
required Main-chain liquid crystal elastomers (MCLCEs)
show large response to changes in temperature especially
in the vicinity of a phase transition Liquid crystalline
main-chain polymers with photoactive moieties have been
electrospun into highly oriented fibers using in situ UV
Fig 9 Strain response of two similar transducers built on NafionTM mat
and film Reproduced with permission from [103] C Nah et al ComposSci Technol 68 2960 (2008) copy 2008 Elsevier
Fig 10 Thermoelastic curves on cooling with different preload Repro-
duced with permission from [105] S Krause et al Macromol RapidCommun 28 2062 (2007) copy 2007 Wiley-VCH Verlag GmbH amp Co
KGaA
curing105 The resulting thin film mats show excep-
tional mechanical properties such as large temperature-
dependent changes in length and a nonlinear stressndashstrain
relation (Fig 10)
3 CHALLENGES AND OPEN QUESTIONS
There has been tremendous surge in the development of
electrospinning technology and applications since the year
2000 but there are still several issues not yet resolved
First more experimental studies and theoretical model-
ing are needed to achieve greater control over the size
and morphology of electrospun fibers and a better under-
standing of the correlation between electronic properties
and the spun fiber morphology Additionally the diversity
and scope of materials that can be used with an electro-
spinning process must be greatly expanded Some non-
spinnable conducting polymers can be electrospun with
other spinnable polymers in the form of corendashshell struc-
tures or as coatings of a conducting polymer on the surface
of another polymer fiber mat The number of corendashshell
structures must be expanded for electrospinning technol-
ogy to meet expanding application demands Melt elec-
trospinning and in-flight polymerization electrospinning
are still rather nascent technologies and will require sig-
nificant development Also the current scale of standard
electrospinning equipment cannot meet the widespread
manufacturing demand Although using multi-spinneret
techniques can achieve high mass throughput the cost
of this new equipment may prevent its increased use in
manufacturing As these techniques are perfected and new
processes developed electrospinning may become more
critical in the fields of nanotechnology and bioengineering
J Nanosci Nanotechnol 10 5507ndash5519 2010 5517
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354R
EVIEW
Electrospinning of Nanomaterials and Applications in Electronic Components and Devices Miao et al
4 CONCLUSION AND PROSPECTS
Current advances in electrospinning technology are
providing important evidence for new potential roles of
electrospun materials in energy conversion and storage
applications The electrospun porous fiber mats used as a
separator in Li-ion batteries will improve ion-conductivity
thereby enhancing battery efficiency The use of elec-
trospun porous fiber mats as electrodes in both Li-ion
batteries and supercapacitors will undoubtedly improve
the cycle life and increase rate capabilities and capaci-
tance Porous fibers also have good mechanical strength
and will certainly improve the performance of polymer
actuators Electrospinning also offers a technique to pre-
pared nanoscale electrical components for the construc-
tion of nanodevices and nanomachines Electrospinning
using RTILs as biopolymer solvents represent ldquogreenrdquo
electrospinning techniques as biopolymers are renewable
and recyclable and RTILs are non-volatile and also eas-
ily recycled Such ldquogreenrdquo technology makes electrospin-
ning a sustainable and environmentally friendly processing
method
Acknowledgments We gratefully acknowledge
Chisso Corporation Tokyo Japan and the Rensselaer
Nanotechnology Center for their support of our research
on electrospinning
References and Notes
1 A Formhals US Patent No 1975504 (1934)2 A Formhals US Patent No 2160962 (1939)3 G Taylor Proc R Soc London A 313 453 (1969)4 P Baumgarten J Colloid Interface Sci 36 71 (1971)5 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 909 (1981)6 L Larrondo and R S J Manley J Polym Sci B Polym Phys
19 921 (1981)7 D H Reneker and I Chun Nanotechnology 7 216 (1996)8 J Doshi and D H Reneker J Electrost 35 151 (1995)9 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
17 1769 (2007)10 H Bai L Zhao C H Lu C Li and G Q Shi Polymer 50 3292
(2009)11 P P Yang J F Chen Z H Huang S M Zhan Z J Jiang Y Q
Qiu and C Shao Mater Lett 63 1978 (2009)12 G Viswanathan S Murugesan V Pushparaj O Nalamasu P M
Ajayan and R J Linhardt Biomacromolecules 7 415 (2006)13 R Sheldon Chem Commun 37 2399 (2001)14 M C Buzzeo C Hardacre and R G Compton Anal Chem
76 4583 (2004)15 T Welton Chem Rev 99 2071 (1999)16 R Kostecki L Norin X Y Song and F McLarnon
J Electrochem Soc 151 A522 (2004)17 S S Zhang J Power Sources 164 351 (2007)18 K M Abraham M Alamgir and D K Hoffman J Electrochem
Soc 142 683 (1995)19 A Frenot and I S Chronakis Curr Opin Colloid Interface Sci
8 64 (2003)20 Z M Huang Y Z Zhang M Kotaki and S Ramakrishna
Compos Sci Technol 63 2223 (2003)
21 V Thavasi G Singh and S Ramakrishna Energy Environ Sci1 205 (2008)
22 C R Yang Z D Jia Z C Guan and L M Wang J PowerSources 189 716 (2009)
23 K Gao X G Hu C S Dai and T F Yi Mater Sci Eng B131 100 (2006)
24 Z B Huang D S Gao Z H Li G T Lei and J Zhou ActaChim Sinica 65 1007 (2007)
25 T H Cho M Tanaka H Onishi Y Kondo T Nakamura
H Yamazaki S Tanase and T Sakai J Power Sources 181 155
(2008)26 T H Cho T Sakai S Tanase K Kimura Y Kondo T Tarao and
M Tanaka Electrochem Solid State Lett 10 A159 (2007)27 P Raghaven J W Choi J H Ahn G Cheruvally G S Chauhan
H J Ahn and C Nah J Power Sources 184 437 (2008)28 M A Kader S K Kwak S L Kang J H Ahn and C Nah
Polym Int 57 1199 (2008)29 S H Park J U Kim S Y Lee W K Lee J K Lee and M R
Kim J Nanosci Nanotechnol 8 4889 (2008)30 Y X Gu D R Chen and M L Jiao J Phys Chem B 109 17901
(2005)31 A K Alves F A Berutti F J Clemens T Graule and C P
Bergmann Mater Res Bull 44 312 (2009)32 K Onozuka B Ding Y Tsuge T Naka M Yamazaki S Sugi
S Ohno M Yoshikawa and S Shiratori Nanotechnology 17 1026(2006)
33 S M Jo M Y Song Y R Ahn C R Park and D Y Kim
Journal of Macromolecular Science-Pure and Applied Chemistry A42 1529 (2005)
34 M Y Song D K Kim K J Ihn S M Jo and D Y Kim SynthMet 153 77 (2005)
35 L W Ji and X W Zhang Electrochem Commun 11 1146 (2009)36 L W Ji and X W Zhang Electrochem Commun 11 795 (2009)37 C Kim K S Yang M Kojima K Yoshida Y J Kim Y A Kim
and M Endo Adv Funct Mater 16 2393 (2006)38 L Wang Y Yu P C Chen D W Zhang and C H Chen J Power
Sources 183 717 (2008)39 C K Chan H L Peng G Liu K McIlwrath X F Zhang R A
Huggins and Y Cui Nat Nanotechnol 3 31 (2008)40 H Kim B Han J Choo and J Cho Angew Chem Int Ed
47 10151 (2008)41 P G Bruce B Scrosati and J M Tarascon Angew Chem Int
Ed 47 2930 (2008)42 H W Lu L Yu W Zeng Y S Li and Z W Fu Electrochem
Solid State Lett 11 A140 (2008)43 H W Lu W Zeng Y S Li and Z W Fu J Power Sources
164 874 (2007)44 Y X Gu D R Chen X L Jiao and F F Liu J Mater Chem
16 4361 (2006)45 C Arribas and D Rueda Synth Met 79 23 (1996)46 W J Lee Y J Kim M O Jung D H Kim D L Cho and
S Kaang Synth Met 123 327 (2001)47 Y W Ju J H Park H R Jung and W J Lee Electrochim Acta
52 4841 (2007)48 Q Fan and M S Whittingham Electrochem Solid State Lett
10 A48 (2007)49 P Poizot S Laruelle S Grugeon L Dupont and J M Tarascon
Nature 407 496 (2000)50 H W Lu D Li K Sun Y S Li and Z W Fu Solid State Sci
11 982 (2009)51 Y X Gu and F F Jian J Phys Chem C 112 20176 (2008)52 Y H Ding P Zhang Z L Long Y Jiang J N Huang W J Yan
and G Liu Mater Lett 62 3410 (2008)53 B Oregan and M Gratzel Nature 353 737 (1991)54 S Chuangchote T Sagawa and S Yoshikawa Appl Phys Lett
93 033310 (2008)
5518 J Nanosci Nanotechnol 10 5507ndash5519 2010
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
(2000)96 R H Baughman Synth Met 78 339 (1996)97 J D Madden R A Cush T S Kanigan and I W Hunter Synth
Met 113 185 (2000)98 S Brady D Diamond and K T Lau Sens Actuators A 119 398
(2005)99 S J Kim M S Kim S I Kim G M Spinks B C Kim and
G G Wallace Chem Mater 18 5805 (2006)100 A Sidorenko T Krupenkin A Taylor P Fratzl and J Aizenberg
Science 315 487 (2007)101 Y A Ismail M Y Shin and S J Kim Sens Actuator B-Chem
136 438 (2009)102 G Y Yun H S Kim J Kim K Kim and C Yang Sens
Actuators A 141 530 (2008)103 C Nah Y S Lee B H Cho H C Yu B Akle and D J Leo
Compos Sci Technol 68 2960 (2008)104 R Samatham I S Park K J Kim J D Nam N Whisman and
J Adams Smart Mater Struct 15 N152 (2006)105 S Krause R Dersch J H Wendorff and H Finkelmann Macro-
mol Rapid Commun 28 2062 (2007)
Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519
Delivered by Ingenta toRensselaer Polytechnic Institute
IP 1281132688Wed 23 Jun 2010 180354
REVIEW
Miao et al Electrospinning of Nanomaterials and Applications in Electronic Components and Devices
55 M Y Song D K Kim S M Jo and D Y Kim Synth Met155 635 (2005)
56 M Y Li G Y Han and B S Yang Electrochem Commun10 880 (2008)
57 N Koshizaki K Suga and K Yasumoto Denki Kagaku 64 1293
(1996)58 K M Sawicka A K Prasad and P I Gouma Sens Lett 3 31
(2005)59 W Y Wu J M Ting and P J Huang Nanoscale Res Lett 4 513
(2009)60 S Piperno M Passacantando S Santucci L Lozzi and S LaRosa
J Appl Phys 101 124504 (2007)61 I D Kim A Rothschild B H Lee D Y Kim S M Jo and
H L Tuller Nano Lett 6 2009 (2006)62 D Lin H Wu R Zhang and W Pan Nanotechnology 18 465301
(2007)63 A F Lotus S Bhargava E T Bender E A Evans R D Ramsier
D H Reneker and G G Chase J Appl Phys 106 014303 (2009)64 H S Shim S I Na S H Nam H J Ahn H J Kim D Y Kim
and W B Kim Appl Phys Lett 92 183107 (2008)65 D Lin H Wu and W Pan Adv Mater 19 3968 (2007)66 H Wu D D Lin and W Pan Appl Phys Lett 89 133125 (2006)67 X F Lu D L Zhang Q D Zhao C Wang W J Zhang and
Y Wei Macromol Rapid Commun 27 76 (2006)68 L Pintilie M Alexe I Pintilie and T Botila Appl Phys Lett
69 1571 (1996)69 D D Lin H Wu W Zhang H P Li and W Pan Appl Phys
Lett 94 172103 (2009)70 Z Y Hou C X Li J Yang H Z Lian P P Yang R T Chai
Z Y Cheng and J Lin J Mater Chem 19 2737 (2009)71 H W Song H Q Yu G H Pan X Bai B Dong X T Zhang
and S K Hark Chem Mater 20 4762 (2008)72 J Wu and J L Coffer Chem Mater 19 6266 (2007)73 M Bashouti W Salalha M Brumer E Zussman and E Lifshitz
Chem Phys Chem 7 102 (2006)74 E Formo M S Yavuz E P Lee L Lane and Y N Xia J Mater
Chem 19 3878 (2009)75 H J Kim Y S Kim M H Seo S M Choi and W B Kim
Electrochem Commun 11 446 (2009)76 R Kotz and M Carlen Electrochim Acta 45 2483 (2000)77 K S Yang C Kim S H Park J H Kim and W J Lee
J Biomed Nanotechnol 2 103 (2006)78 C Kim Y O Choi W J Lee and K S Yang Electrochim Acta
50 883 (2004)79 S H Park C Kim and K S Yang Synth Met 143 175 (2004)80 C Kim S H Park W J Lee and K S Yang Electrochim Acta
50 877 (2004)81 C Kim J Power Sources 142 382 (2005)
82 C Kim K S Yang and W J Lee Electrochem Solid State Lett7 A397 (2004)
83 Y W Ju S H Park H R Jung and W J Lee J ElectrochemSoc 156 A489 (2009)
84 Q H Guo X P Zhou X Y Li S L Chen A Seema A Greiner
and H Q Hou J Mater Chem 19 2810 (2009)85 J S Im S W Woo M J Jung and Y S Lee J Colloid Interface
Sci 327 115 (2008)86 Y W Ju G R Choi H R Jung and W J Lee Electrochim Acta
53 5796 (2008)87 S J Park and S H Im Bull Korean Chem Soc 29 777
(2008)88 C X Zhang X Y Yuan L L Wu Y Han and J Sheng Eur
Polym J 41 423 (2005)89 C Kim B T N Ngoc K S Yang M Kojima Y A Kim Y J
Kim M Endo and S C Yang Adv Mater 19 2341 (2007)90 S K Nataraj B H Kim J H Yun D H Lee T M Aminabhavi
and K S Yang Mater Sci Eng B-Adv Funct Solid-State Mater162 75 (2009)
91 J S Im S J Park and Y S Lee J Colloid Interface Sci 314 32(2007)
92 J Li E H Liu W Li X Y Meng and S T Tan J Alloys Compd478 371 (2009)
93 H D Nguyen J M Ko H J Kim S K Kim S H Cho J D
Nam and J Y Lee J Nanosci Nanotechnol 8 4718 (2008)94 Y W Ju G R Choi H R Jung C Kim K S Yang and W J
Lee J Electrochem Soc 154 A192 (2007)95 E W H Jager E Smela and O Inganas Science 290 1540
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Received 29 October 2009 Accepted 8 March 2010
J Nanosci Nanotechnol 10 5507ndash5519 2010 5519