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NANO SCIENCE & ENGINEERING IN MECHANICS
by
Ken P. Chong PhD, PE, Hon. M.ASCE, F.AAM
Director of Mechanics & Materials ProgramNational Science Foundation
www.nsf.gov
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ion creation of new materials, devices and
systems at the molecular level
phenomena associated w/ atomic & molecular interactions strongly influence macrospic mat’l properties [I. Aksay, Princeton]
significantly improved mechanical, optical, chemical, electrical... properties
“there is plenty of room at the bottom” [Richard Feynman, 1959]
“nanoscale technology will have an impact equal to the Industrial Revolution” [Rita Colwell, 2002]
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ion 1 nm ~ 5 atoms length
ductile ceramics [w/ grain size in low nm range]
fireflies convert chemical energy to light w/ near-perfect efficiency [ ME, Nov. ‘00]
nano-photosynthesis: green technology
MEMs as platform for NEMS
bio-nanotechnology
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M. ROCO, ~2002
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ion Organizations that have prepared and contribute to
the National Nanotechnology Initiative (NNI)
Office of Science and Technology Policy (OSTP)National Science and Technology Council (NSTC)
White House
DepartmentsDOC/NIST, DOD, DOE, DOJ,
DOS, DOT, DOTreas, DHS, USDA
IWGN (October 1998-August 2000)
NSET (August 2000 - continuing)
Independent AgenciesEPA, FDA, NASA, NIH, NRC, NSF, USG
Federal Government R&D funding NNI (~$700M in 02)Industry (private sectors) ~ NNI fundingState and local (universities, foundations) ~ 1/2 NNI funding
Est.:
M.C. Roco, NSF, 5/29/03
Office of Management and Budget (OMB)Presidential Council of Advisors in Science and Technology (PCAST)
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ion Nanoscale Science and Engineering
support at NSF in FY 2004 The budget allocation expected between
$249M (NSF Request) and $350M (Congress bills)
• Program solicitations (about $91M, about 1/3) Nanoscale Science and Engineering - $79M, NSF 03-043 Nanoscale Science and Engineering Education - $12M, NSF
03-044• Support in the core program (about 2/3) with focus on single
investigator & other core Various research and education programs in all directorates Interdisciplinary fellowships; STC, MRSEC and ERC centers Instrumentation (REG, MRI); Collaboration industry (GOALI, PFI); Network for Computational Nanotechnology ($2.8M/yr); National Nanotechnology Infrastructure Network ($14M/yr); Nanoscale Informal Science and Education (NSF 03-511)
• SBIR/STTR (additional ~ $10M)M.Roco, NSF, 9/29/03
Fundamental nanoscale science and eng’g - Principal Areas of Investigation – core programs (FY 2002)
• Biosystems at the Nanoscale ~ 14%
biostructures, mimicry, bio-chips• Nanostructure ‘by Design’, Novel Phenomena 45%
physical, biological, electronic, optical, magnetic• Device and System Architecture 20%
interconnect, system integration, pathways• Environmental Processes 6 %
filtering, absorption, low energy, low waste• Multiscale and Multiphenomena Modeling 9 %• Manufacturing at the nanoscale 6%• Education and Social Implications (distributed)
M.C. Roco, NSF, 01/31/03
Grand Challenges (NNI, FY 2002)
• Nanostructured materials "by design" ~ 22%• Nanoelectronics, optoelectronics and magnetics 39%• Advanced healthcare, therapeutics, diagnostics 8% • Environmental improvement 4%• Efficient energy conversion and storage 5%• Microcraft space exploration and industrialization 3%• CBRE Protection and Detection (revised in 2002) 7%• Instrumentation and metrology 6%• Manufacturing processes 5%
(details in the NNI Implementation Plan, http://nano.gov)
M.C. Roco, NSF, 01/31/03
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ion NSF - a pioneer among Federal agencies
and at the international level in Nanoscale Science and Engineering (NSE)
FY 2003: ~ 1/3 of Federal and 1/10 of World Investment– Seven themes: Biotechnology, Nanostructures ‘by design’ and novel
phenomena, Device and system architecture, Environmental Processes, Multiscale modeling, Nanoscale manufacturing; Societal implications and Improving human performance
– Establishing the infrastructure: over 1,600 active projects; 20 large centers, 2 user facilities (NNIN, NCN), multidisciplinary teams
– Training and education over 7,000 students and teachers
Fiscal Year NSF HR7662000 $97M2001 $150M2002 $199M2003 $221M
R 2004 $249M $350M0
50
100
150
200
250
300
350
2000 2001 2002 2003 2004R
NSE ($M)Congr. Bill
M.C. Roco, 10/09/03
Nanotechnology R&D Funding by Agency
Fiscal year 2000 2001 2002 2003 2004 (all in million $) Enacted/actual Enacted/actual Requests
__________________________________________________________________________________________________________________________________________________________________
National Science Foundation 97 150 /150 199 / 204 221 249Department of Defense 70 110 /125 180 /180 243 222Department of Energy 58 93 /88 91.1 /89 133 197National Institutes of Health 32 39 /39.6 40.8 /59 65 70 NASA 5 20 /22/ 35 /35 33 31NIST 8 10 /33.4 37.6 /77 69 62 Environmental Protection Agency - /5.8 5 /6 6 5Homeland Security (TSA) - 2 /2 2 2Department of Agriculture - /1.5 1.5 /0 1 10Department of Justice - /1.4 1.4 /1 1.4 1.4
TOTAL 270.0 422.0 /464.7 ~ 600 /653 ~ 774 ~ 849
Other NNI participants are: OSTP, NSTC, OMB, DOC, DOS, DOTreas, FDA, NRC, DHS, IntelM.C. Roco, NSF, 2/20/03
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BASIC INSTRUMENTS & TOOLS
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Principle of AFM
SEM image of the AFM cantilever and tip.
http://www.di.com/app_notes/spmtechnology_appnotes.htm
MEASURE FORCE F = F(d)
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•LIMITATIONS
AFM SCAN SPEED ~100HZ [TAKES ~30 MIN. FOR A SMALL IMAGE OF 20,000 PIXELS]
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NEMSNano-photosynthesisCyberinfrastructure
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LDLM Large Deformation Laser MoireFGLM Fine Grating Laser MoireLSI Laser Speckle InterferometryDIC Digital Image Correlation
HRTEM High Resolution Transmission Electron MicroscopyCFTM Computational Fourier Transform MoireAFM Atomic Force MicroscopySEM Scanning Electron MicroscopySRES Surface Roughness Evolution Spectroscopy
Map of Deformation-Measurement Techniques
Interface Energy Limit
Interferometric Gain
of Resolution
HRTEM-CFTM
LDLM
DIC
SRES
FGLM & LSI
Field Projection Method
Equilibrium Smoothing
Field of View (Gage Length in )mSt
rain
Res
olut
ion
10 -1
10 -9
10 -8
10 -7
10 -6
10 -5
10 -4
10 -3
10 -2
10 -1
10 -2
10 -3
10 -4
10 -5
10 -6
AFM Interferometry
NSF Award No. CMS-0070057, Engineering Directorate (Program Manager: Dr. K.P. Chong & Jorn Larsen-Basse)
K.-S. Kim, Nano & Micromechanics Laboratory, Brown University
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L. SUNG, NIST
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Van der Waals Force
www.topometrix.com/spmguide/1-2-0.htm
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EDUCATION• 10-12 m QUANTUM MECHANICS [TB, DFT, HF…]
• 10-9 MOLECULAR DYN. [LJ…]; NANOMECHANICS;MOLECULAR BIOLOGY; BIOPHYSICS
• 10-6 ELASTICITY; PLASTICITY; DISLOCATION...
• 10-3 MECHANICS OF MATERIALS
• 10-0 STRUCTURAL ANALYSIS
MULTI-SCALE ANALYSES & SIMULATIONS…____________________________________________________________TB = TIGHT BINDING METHOD; DFT = DENSITY FTNAL THEORY;
HF = HATREE-FOCK APPROX.; LJ = LENNARD JONES POTENTIAL
• NSF SUMMER INSTITUTE OF NANOMECHANICS & MAT’LS, NORTHWESTERN UNIVERSITY –contact: PROF. W.K. LIU
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CHALLENGES
multi-scale
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BORESI AND CHONG, ELASTICITY IN ENGINEERING MECHANICS, WILEY, 2000.
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Qualitative Predictions Quantitative PredictionsStructuralMechanics
Molecular Assembly
Computational Chemistry
Computational Materials
Computational Mechanics
• Electrons• Nuclei• Atoms
• Molecular fragments• Bond angles• Force Fields
• Surface Interactions• Orientation• Crystal Packing• Molecular Weight• Free Volume
• Constituents• Interphase • Damage
Fiber
Matrix
Length, (m)
10-12 10-9 10-6 10-3 100
Nano MesoQuantum Micro
NASA Langley Research CenterNanotechnology Modeling and Simulation
Macro
C
C
C
CO
CO
CO
CO2
CO2
CO2
CO
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MultiMulti--Scale MultiScale Multi--Phenomena Modeling of Phenomena Modeling of
Structure / Property / Structure / Property / FunctionFunction
10 µm
Multi-Scale Composite
Epoxy Matrix
Nanocomposite1 µm
CarbonFiber
Nanocomposite
Carb
on
Fibe
r
100 nmCarbon Nanotubes
1 nmZig-ZagArmchairAtomic Interactionsr0
Stretching 0θ
Bending
Torsionvan der Waals
1 ÅModelin
g Hierarchy – Bridging th
e Scale from Nano to
Macro
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ionModeling and Measuring the Structure and Properties of Cement-Based
Materials
http://ciks.cbt.nist.gov/monograph/
Over 10,000 users from 83 countries per month
MODEL
nmnmmm
mmmmREAL
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ion Atomistic Modeling of the Contact Problem
Repulsive potential indenter:Findenter ~ (R-r)2 for r<R
Rr
Fixed B.C
.
Fixed B.C
.
Fixed B.C.
Free surface Free surface y
z
x
EAM constitutive law: Ecoh = Gii∑ ρ j
a Rij( )i≠ j∑
+12
Uiji, j j≠i( )
∑ Rij( )
ˆ y ˆ x
ˆ z
E. T. Lilleodden, J. Zimmerman, S. Foiles and W.D. Nix
William D. Nix, Stanford University
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ion Atomistic Calculation of Indentation Response
0
50
100
150
0 2 4 6 8 10
S
Sneddon’s analysis of Unloading Curve:
Hertz’s loading equation:
Depth (Å)
Load (nN)
168,000 atoms, (001) surface of Au indented
P = 4 / 3( )E* Rh3/2
E*=89 GPaE* = S π
2 A= 90 GPa
E. T. Lilleodden, J. Zimmerman, S. Foiles and W.D. Nix
William D. Nix, Stanford University
The MD calculations mirror the experiments; here displacement bursts result in a load drop rather than a displacement excursion because the MD calculations represent a “hard testing” machine. The elastic responses are correctly modeled.
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RAJIV KALIA, LSU
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ion DISCUSSIONS OF COMMON
MODELING METHODS• FIRST PRINCIPLE CALCULATIONS - TO SOLVE
SCHRODINGER’S EQ. AB INITIO, e.g. HATREE- FOCK APPROX., DENSITY FUNCTIONAL THEORY,… - COMPUTIONAL INTENSIVE, O(N4)- UP TO ~ 3000 ATOMS
• MOLECULAR DYNAMICS [MD] - DETERMINISTIC, e.g. W/ LENNARD JONES POTENTIAL- MILLIONS TIMESTEPS OF INTEGRATION; TEDIOUS- UP TO ~ BILLION ATOMS FOR NANO-SECONDS
• COMBINED MD & CONTINUUM MECHANICS [CM], e.g. MAAD; LSU; BRIDGING SCALE; …- PROMISING...
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CNTs
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ion CARBON NANOTUBES [CNT]
• honeycomb lattices of carbon rolled into cylinders; nm in diameter, micron in length
• 1/6 the wt. of steel; 5 times E; 100 times tensile strength; 6 orders of magnitude higher in electrical conductivity than copper; MWNT strains up to 15%
• 10 times smaller than the smallest silicon tips in STM [CNT is the world’s smallest manipulator]
• CNT may have more impact than transisters
• ideal mat’l for flat-screen TV [~2003]
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ion CNT, CONT’D
• self-assemble in deposition from C-rich vapors
• similar diameter as DNA• bridge different scales in mesoscale - useful
as bldg. blocks ~ e.g. nanocomposites;gases storage
• metallic or semiconducting• as single-electron transistor; logic gate• as RAM - on/off do not affect memory storage
- no booting needed
CARBON NANOTUBES -THE FIRST 10 YEARS, NATURE, 2001.MECHANICAL ENGINEERING, ASME, NOV. 2000TECHNOLOGY REVIEW, MIT, MAR. 2002
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(n, 0) Zigzag
(n, n) Arm Chair
Others Chiral
Diameter and helicity are characterized by (n, m)
Electronic properties depend on (n, m), exhibiting metallic or semiconducting behavior
Figs. by Yong Zhu/Rod Ruoff, Northwestern U.
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MOLECULAR STRUCTURAL MECHANICS APPROACH
Computational Chemistry
MolecularMolecularStructuralStructuralMechanicsMechanics
ComputationalMechanics
Computational Chemistry
MolecularMolecularStructuralStructuralMechanicsMechanics
ComputationalMechanics
Merging of Chemistry and Mechanics
Bond Beam
Nanotube Space Frame
T.-W. Chou, U. DE
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NNL
MML 0θ
T TL
r0
Structural Mechanics Molecular Mechanics
CORRESPONDING RELATION OF PARAMETERS
τ=kL
GJ
θ= kLEI
rkL
EA=
Li and Chou, International Journal of Solids and Structures (2003)Li and Chou, Physical Review B (2003)
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LINKAGE BETWEEN COMPUTATIONAL STRUCTURAL MECHANICS AND COMPUTATIONAL CHEMISTRY
• Energy conservation principle is universal
• Structural mechanics can be established based on strain energy theory
• Computational chemistry is based on steric potential energy theory (molecular force field)
• Energy equivalence can be used to provide a link between computational structural mechanics and computational chemistry
T.-W. Chou, U. DE
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ion BUCKLING PRESSURE OF SWNT
0.5 1.0 1.5 2.0
2
4
6
8
10
12
Nanotube diameter (nm)
Buc
klin
g pr
essu
re (G
Pa) Experiment(Tang et al.)
ab initio (Reich et al.) Experiment(Chesnokov et al.) Zigzag Armchair
Li and Chou, Physical Review B (2004), Li and Chou, Mechanics of Materials (2004)
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OTTO ZHOU, UNC-CH~15% strain
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ion MULTI – SCALE HYBRID
COMPOSITES: BRIDGING THE MICRO AND NANO SCALES
1 mm
500 nm
1 µm
5 nm5 nmThostenson et al., Journal of Applied Physics (2002)Thostenson and Chou, Journal of Physics D: Applied Physics (2003)
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10
100
1000
1 10 1000.1
SpecificModulusGPa/(g/c3)
Specific Strength, GPa/(g/c3)0.2 0.5 2 5 20 50
20
50
200
500
Aluminum 2219
Baseline Material,available today
Best availableunder development
CFRP Composite
Properties of Carbon Properties of Carbon Nanotubes Nanotubes (CNT)(CNT)
CNTFRP Composite
Single Crystalbulk material (CNT)
Emerging material, carbon nanotubes
Long-term potentialof CNT material
from NASA-larc
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MIT
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sensors, smart, bio, nanomaterials
…
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C. ROGERS
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Artificial NOSE – Operation principleEight cantilevers functionalized with eight different polymers or blends
H.P. Lang, M.K. Baller, Ch. Gerbe
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NIST 2 m Integrating Sphere
Simulated
Photodegradation via
High
Energy
Radiant
Exposure
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ion Integrating Sphere Technology
Characteristics of Integrating Sphere Output:• Uniform diffuse radiation• Constant radiance and irradiance at exit port.• Constant irradiance between exit ports
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ion Polymeric Materials Requiring UV Exposure
• Coatings• Textiles• Vinyl Siding• Bulk Plastics• Asphalt *• Roofing membranes/shingles• Sealants *• Geotextiles *• Fiber-reinforced composites ** Load bearing
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ion Polymer Nanocomposites NIST
• Flame retardant materials• Conducting polymers• Scratch resistant coatings• Self-healing materials• Self-disinfecting surfaces…
Carbon NanotubesSiO2
ZnO
TiO2
Layered Silicates
Polyethylene
EpoxyPolypropylene
Polystyrene
PDMS
Nylon
PMMA
Polyurethane
TPOAg
Nanowires
Quantum Dots
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ion Nano-Clay Filled Polymers NIST
Si
OAl, Mg
OH
• Certain types of clay naturally form platelet structures– Thickness just less than 1 nm– High aspect ratios
• Lengths and widths are 25 to 2000 times the thickness
– Gallery spacing between platelets between 1.5 nm and 2 nm
• Contain cations for charge balance– Hold platelets together
• Use of just 1% to 5% by volume can dramatically alter material behavior– Properties related to flammability
improved– Mechanical properties improved– Improvements often depend on ability
to separate and disperse platelets• Organic treatment needs to be
thermally stable.
~ 1 nm
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ion Metal Oxide Nanoparticles in Coatings
• TiO2 and ZnO used in nanosize forms in sunscreens– Photoreactive behavior
• Good absorbers of UV light• Deactivate and destroy:
– Bacteria, viruses, fungi– Organic and inorganic
pollutants in air and water– Cancer cells
• Producing energy viaphotoelectrochemical cells
• Applications include:– “Self-disinfecting” surfaces– Paints and coatings with improved
durability– Indoor air cleaners– Water treatment– Mitigation of air-borne biological
agents– Solar cells
CB
VB
hυ H2O
H2O
H2OO2
O2
O2 O2hole +
electron –
If charge carriers get to surface:O2
- superoxideOH. hydroxyl radicalH2O2 hydrogen peroxide
and other activated oxygen species can be generated.
All are capable of further reaction with organic materials for good or bad
NIST
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ion www.nsf.gov
Chong, K. P., “Research and Challenges in Nanomechanics” 90-minute Nanotechnology Webcast, ASME, Oct. 2002; archived in www.asme.org/nanowebcast
NSF SUMMER INSTITUTE ON NANO MECHANICS & MATERIALShttp://tam.northwestern.edu/summerinstitute/Home.htm
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NSF Summer Institute on Nano Mechanics and Materials*
Co-sponsored by
Northwestern University, American Society of Mechanical Engineering,
NASA URETI BIMat Center, Northwestern University Materials Research Center,
NU Nanoscale Science and Engineering Center, Northwestern University, CSET, NSF IGERT on virtual tribology and AVS Science & Technology
Society.
Professor Wing Kam Liu (Director) Professor Ted Belytschko (Co-Director) Professor Yip Wah Chung (Co-Director)
*Funded by the Civil and Mechanical Systems Division, monitored and guided by Dr. Ken P. Chong, Prog. Director.
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ion Defining the vision and implementation planDefining the vision and implementation plan
National Nanotechnology InitiativeNational Nanotechnology Initiative
ReportsReports
Planning with feedback after each: 5 years, 1 year, 1 month; and various levels: national/NSET, agency, program
In preparation: Topical reports; new 2004:10 year vision
1999: 10-year vision
MC. Roco, 10/09/03
Worldwidebenchmark
Brochure forpublic
Societalimplications
Govtplan
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ion SUMMARY & DISCLAIMER
An overview of major advances, challenges and research concerning mechanics and materials are presented. The author would like to thank his colleagues and many members of the research communities for their comments and input during the writing of this presentation.Information on NSF initiatives, announcements and awards can be found in the NSF website: www.nsf.gov. The opinions expressed in this article are the author’s only, not necessarily those of the National Science Foundation [NSF] or NIST. Any commercial products identified are for illustrations only, do not imply any endorsement.
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Questions/comments?
