Chandigarh - IEEE · Chandigarh Cambridge Gaurav Verma PhD Raman Fellow & Visiting Faculty Massachusetts Institute of Technology Cambridge, MA Assistant Professor (Polymers) / Co-coordinator

Chandigarh

Cambridge

Gaurav Verma PhD

Raman Fellow & Visiting Faculty

Massachusetts Institute of Technology

Cambridge, MA

Assistant Professor (Polymers) / Co-coordinator

Chemical Engg/Nanoscience & Nanotechnology Panjab University, Chandigarh India

Gaurav Verma, MIT ([email protected])


Adding newer dimensions to Materials Science-an era of Nanotechnology

Structure

Application Gaurav Verma, MIT ([email protected])

Gau

rav

Ve

rma,

MIT

(gv

erm

a@m

it.e

du

)

Nano is a Perspective of looking at things………



Nano-scale

Realm: 10-9 m

Inter-face

Surface area

Manipulative/Controllable

Novel Nature

Self-Assembly

Symmetry


Researchers use a near-infrared microscope to read the output of carbon nanotube sensors embedded in an Arabidopsis thaliana plant.

Augmenting them with nanomaterials

that could enhance their energy production

Boosting plants’ ability to capture light

energy by 30 percent by embedding carbon

nanotubes in the chloroplast

Plant nanobionics approach to augment photosynthesis and biochemical Sensing, Strano et al; Nature Materials 13, 530 (2014) .


Plants typically make use of

only about 10 percent of the

sunlight available to them, but

carbon nanotubes could act as

artificial antennae that allow

chloroplasts to capture

wavelengths of light not in

their normal range, such as

ultraviolet, green, and near-

infrared.

Combining inorganic with

organic matter to enhance

functions and capabilities. Figure | SWNT transport and trapping by lipid bilayers


Plasmonic nanosensors with inverse sensitivity by means of enzyme- guided crystal growth, Stevens et al; Nature Materials 11, 604–607 (2012)

Early disease detection by picking up biomarker signals at very low concentrations Detecting prostate specific antigen (PSA) in concentrations nine orders of magnitude smaller than today's enzyme-linked immunosorbent assay (ELISA) tests.

Gold nanoparticles float in proteins derived from blood serum

Gau

rav

Ve

rma,

MIT

(gv

erm

a@m

it.e

du

)

In Vivo Silicon-Based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers. Hwang et al; ACS Nano, 2013, 7 (5)

Silicon-based semiconductors perform significant roles of nerve stimulation, signal

analysis, and wireless communication in implantable electronics.

Flexible LSI in biointegrated electronics such as an artificial retina and wireless body

sensor networks.

Gau

rav

Ve

rma,

MIT

(gv

erm

a@m

it.e

du

)

Polymer-nano composite coatings for different applications-

automotive coatings

Improving growth of crops using CNTs

Fabrication of graphene based coatings for electronic applications

Restoration & Preservation of heritage buildings and structures.

Comparative assessment of nano-morphology and properties of spray coated clear polyurethane coatings reinforced with different organoclays Verma et al, Progress in Organic Coatings, Volume 76, Issues 7–8, July–August 2013, Pages 1046-1056 Preparation, characterization and properties of organoclay reinforced polyurethane nanocomposite coatings Verma et al; Journal of Plastic Film and Sheeting, January 2013; vol. 29, 1: pp. 56-77., first published on May 29, 2012


http://www.sciencedirect.com/science/article/pii/S0300944013000428






Mechanism of clay dispersion & exfoliation

Primary organoclay particles (2-13μm)

Platelets intercalated/exfoliated due to diffusion/shear of polymer chains

Stacks or tactoids

Shear

Ultrasonic

Smaller stacks or tactoids

Shear

Swelling

Diffusion by polymer chains

Shear by polymer chains Organoclay platelets (50-500nm)

Organoclay dispersion/exfoliation during nanocomposite processing

High Shear homogenization

Gau

rav

Ve

rma,

MIT

(gv

erm

a@m

it.e

du

)

NANOMORPHOLOGY INVESTIGATIONS: AFM

EFFECT of Clay platelets in PU

EXFOLIATE into matrix, sizes~ 85-250nm

SELF ORGANISE the PU HARD DOMAINS

into ORB-LIKE structures ~ 200-300nm

SELF ASSEMBLY /UNIFORMITY

INCREASE SURFACE SYMMETRY

PU3C30B

PU

PU3C30B

PU3C20A


DIRECT IMPACT INDIRECT IMPACT

COATING FILM

FALLING BALL

MS Panel MS Panel

Figure. Falling ball test: indirect and direct impacts on organoclay-

polyurethane coatings.

3wt% Cloisite 30B polyurethane 3wt% Cloisite 20A

a b c

Figure. Indirect impact samples showing cracks and flakes in a) polyurethane b)

3wt% Cloisite 30B-PU and c) 3wt% Cloisite 20A-PU coatings.

Addition of organoclays had a reinforcing effect on the coatings. The cracks were small and multiple in 3wt% Cloisite 30B-polyurethane and 3wt% Cloisite 20A-polyurethane proving that the cohesive strength in coatings improved with organoclay additions. Also deduced in Contact Angle experiments, rheological experiments. The peel off was also least in Cloisite 30B-polyurethane coatings, and maximum in pristine polyurethane coatings.

Combined mechanical strength like modulus, tensile strength, hardness and adhesion and of the coatings with the substrate => clay reinforces physically and also chemically.

Adhesion and Crack-Impact tests


3wt% C30B-PU

1wt% C30B-PU

1wt% C20A-PU

3wt% C20A-PU

5wt% C20A-PU

5wt% C30B-PU

Polyurethane

Figure. Actual pictures of coated mild steel

panels subjected to salt spray conditions.

Along and around the hatched portion there is

more probability of corrosion, which later

seeps in through to edges.

1wt% C20A-PU

Salt spray conditions-Visual

ASTM Method B-117-95 for 500 hours. Coated mild steel panels are scribed (cut) through the coating in a standardized fashion, exposing bare steel and placed at angle of 15° in a chamber where they are exposed to fumes of a 5% NaCl solution and water at temperatures of 40°C. The edges of the panels are sealed with an adhesive/araldite to avoid initiation of corrosion from sides. The humidity is maintained at about 100%.

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5

% A

rea

corr

od

ed

Organoclay loadings wt%

Cloisite 30B-polyurethane Cloisite20A-polyurethane

Figure. Comparative area corroded polyurethane coatings w.r.t

organoclay loadings%.


Effect of any other paint/‘whitewash’ on Red Sandstone

Completely decolourizes the stones’ original colour and aesthetics

Stone is ultra- sensitive to chemicals: most probably alkalines.

Streaks of water/rust evident


Surface area undertaken for restoration & future preservation using polymer nanocomposite coatings. These are transparent coatings which if made ultra thin can take the shape and configuration of the building material .


Aim: Enhance root growth to make good the reducing levels of water table.

Figure 3: Functionalized MWCNT used for priming the plants. Inset: The MWCNTs look like double head snakes, which can swim across the plant tissues and through cell walls.

Figure : Top: Functionalized MWCNT used for priming the plants. The MWCNTs look like double head snakes, which can swim across the plant tissues and through cell walls. Below: Actual pictures of plant seedlings.


Red-orange colour in xylem-phloem

Figure : Illuminated (fluoresced) Xylem-Phloem of plants due to presence of dye functionalized MWCNT. The root hairs along the cross-section are noticeable. Blow-up of cross-section showing presence of MWCNTs (red-orange) in Xylem-Phloem (inner lining) of plants.

ROOT SHOOT


Red-orange colour in xylem-phloem

Figure : Illuminated (fluoresced) Xylem-Phloem of plants due to presence of dye functionalized MWCNT. The root hairs along the cross-section are noticeable. Blow-up of cross-section showing presence of MWCNTs (red-orange) in Xylem-Phloem (inner lining) of plants.

ROOT SHOOT

Gaurav Verma, ChemE MIT [email protected], [email protected], [email protected]


Documents

Chandigarh - IEEE · Chandigarh Cambridge Gaurav Verma PhD Raman Fellow & Visiting Faculty Massachusetts Institute of Technology Cambridge, MA Assistant Professor (Polymers) / Co-coordinator