Mechanical and Industrial Engineering University of Massachusetts

Amherst, MA, USA

Nano-Impact

Jonathan P. Rothstein1 and Mark Tuominen2

1. Mechanical and Industrial Engineering Dept.2. Physics Dept.University of Massachusetts Amherst

Making a Better Bulletproof Vest

• A group of researchers at Univ. Del. have impregnated Kevlar vests with a nanoparticle colloidal suspension resulting in a dramatic improvement in projectile impact.

• The addition of a very small amount of fluid increased performance equivalent to doubling the number of Kevlar sheets while not changing flexibility of fabric. Why?

Lee, Wetzel and Wagner J. Material Science (2003)

Kevlar Kevlar & Nanoparticle Suspension

Making a Better Bulletproof Vest

• A group of researchers at Univ. Del. have impregnated Kevlar vests with a nanoparticle colloidal suspension resulting in a dramatic improvement in projectile impact.

• The addition of a very small amount of fluid increased performance equivalent to doubling the number of Kevlar sheets while not changing flexibility of fabric. Why?

Kevlar Kevlar & Nanoparticle Suspension

http://www.ccm.udel.edu/STF/images1.html

Nanoparticle Suspensions

• The nanoparticle (d = 13nm) suspensions are shear thickening – the faster you shear or stretch them more viscous (thick) they become.

• The dramatic increase in viscosity dissipates energy as the Kevlar fibers are pulled out by the impact of the bullets. 0.1 1 10 100 1000

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.s]

Shear Rate [s-1]

Increasing Stretch Rate

Why Size Matters

• For large particles the fluid remains Newtonian like air or water below 30wt%• Above 30% interactions between and collisions of particles result shear thickening and elastic effects – particles

interact to form large aggregate structures• For nanoparticles, the effect of nanoparticle addition can be observed at concentrations closer to 1wt% - why?

• Surface area increases with reduced particle size resulting in enhanced interparticle interactions• At same volume fraction smaller particles are packed closer together – electrostatic interactions are stronger

and diffusion is faster so they interact more frequently.

1m Particles100nm Particles

10nm Particles

Copying Nature – Biomimetic Superhydrophobic Surfaces• The leaves of the lotus plant are superhydrophobic – water beads up on the surface of the plant and moves freely with almost no resistance making the leaves self-cleaning.

• The surface of the lotus leaf has 10m sized bumps which are coated by 1nm sized waxy crystals which make the surface extremely hydrophobic - repel water.

• The water does not wet the entire surface of the leaf, but only the tops of the large scale roughness.

• Synthetic superhydrophobic surfaces have designed to produce stain-resistant clothing and coatings for buildings and windows to make them self-cleaning.

Water Drops on a Lotus Leaf

Drop Motion on a Superhydrophobic Surfaces

• Droplets don’t wet, but roll down superhydrophobic surfaces.

• Water-based stains don’t adsorb.

• Dirt is picked up by rolling drop as it moves – self cleaning surfaces

Superhydrophobic Surface

Dirt

Make Your Own Superhydrophobic Surfaces

• Need: two identical pieces of Teflon, sandpaper (240 grit) and a pipette full of water.

• Keep one piece of Teflon smooth.

• Lightly sand the second piece of Teflon with a random motion of the sandpaper to impart micron and nanometer size surface roughness.

Smooth Teflon

Sanded Teflon

Experiment:

•Place a small drop of water on the smooth Teflon surface.•Tilt the surface through vertical.•Does the drop stick or slide?

•Now place a small drop on the sanded Teflon surface•Tilt the surface through vertical.•Can you get the drop to stick?

•Adding micron and nanometer surface roughness can have a big impact on how drops adhere to and wet a surface

Using Superhydrophobic Surfaces to Reduce Drag

• We are currently using superhydrophobic surfaces to develop a passive, inexpensive technique that can generate drag reduction in both laminar and turbulent flows.

• This technology could have a significant impact on applications from microfluidics and nanofluidics to submarines and surface ships.

• How does it work? The water touches only the tops of the post and a shear-free air-water interfaces is supported – effectively reducing the surface area.

• Currently capable of reducing drag by over 70% in both laminar and turbulent flows!

w

d

15μm

On PDMS

Hierarchical Nanostructures On Silicon

Can These Surfaces Have a Real Impact?

60μm

• Current Energy Resources – Fossil Fuels

• Increasing scarcity

• Increasing cost

• Dangerous to maintain security

• Ocean-going vessels accounted for 72% of all U.S. imports in 2006

• Technology could be employed to make ships more efficient or faster

• Friction drag accounts for 90% of total drag experienced by a slow moving vessel

• A 25% reduction in friction drag on a typical Suezmax Crude Carrier could…

• Save $5,500 USD / day in #6 fuel oil

• Prevent 43 metric tons of CO2 from entering the atmosphere each day

The GENMAR GEORGE T (Japan Universal Shipbuilding, Tsu shipyard)

Why Size Matters

• To support larger and larger pressures and pressure drops, the spacing of the roughness on the ultrahydrophobic surfaces must be reduced into the nanoscale.

• Currently developing processing techniques for large area nanofabrication of superhydrophobic surfaces with precise patterns of surface roughness.

→ Roll-to-roll nano-imprint lithography – a cutting edge tool.

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Supply Drive

Module

CoatingModule

ImprintingModule Receive

DriveModule

Why Roll-to-Roll Nanoimprint Lithography

• Roll-to-roll technology will enable fabrication of nanostructured materials and devices by a simple, rapid, high volume, cost-effective platform.

• Current cost of nanofabrication is $25,000/m2

• This technology capable of pushing it to $25/m2

• Will help address many of the challenges facing society.

Supply Drive

Module

CoatingModule

Membranes and Filters

Some key challenges facing society

• Water• Energy• Health• Sustainable development• Environment• Knowledge• Economy

Global Grand Challenges

2008 NAE Grand Challenges

Top Program Areas of the NationalNanotechnology Initiative for 2011

1. Fundamental nanoscale phenomena and processes

2. Nanomaterials3. Nanoscale devices and systems4. Instrumentation research, metrology, and

standards5. Nanomanufacturing6. Major research facilities and instrumentation7. Environment, health and safety8. Education and societal dimensions

484M 342M 402M 77M 101M 203M 117M 35M

http://www.wtec.org/nano2/"Nano2" Report

Nanomanufacturing

• Processes must work at a commercially relevant scale• Cost is a key factor• Must be reproducible and reliable• EHS under control• Nanomanufacturing includes top-down and bottom-up techniques, and integration of both• Must form part of a value chain

Advances in the Last Decade: Nanoparticle Synthesis

The availability of a range of new nanostructures has been facilitated by synthetic control over composition, size and shape.

Nikoobakht, B. et al. Chem. Mater. 2003. 15, 1957.Xia, Y. et al. Angew. Chem. Int. Ed. 2009. 48, 60.Yu, Y. et al. J. Phys Chem. C. 2010. 114, 11119.

Millstone, J. E. et al. J. Am. Chem. Soc. 2005. 127, 5312.Niu, W. et al. J. Am. Chem. Soc. 2009. 131, 697.Zhang, J. et al. J. Am. Chem. Soc. 2010. ASAP.

Advances in the Last Decade: Superlattice Formation and Assembly of Nanostructures

Shevchenko, E. V. et al. Nature 2006. 439, 55.Kalsin, A. M. et al. Science 2006. 312, 420.

Entropic Drying EffectsEntropic Drying Effects Electrostatic Assembly Electrostatic Assembly Directed AssemblyDirected Assembly

Park, S. Y. et al. Nature 2008. 451, 553.Macfarlane, R. J. et al. Angew Chem. Int. Ed. 2010. 49, 4589.

SELF ASSEMBLY with DIBLOCK COPOLYMERS

Block “A” Block “B”

10% A 30% A 50% A 70% A 90% A

~10 nm

Ordered Phases

PMMA PS

Scale set by molecular size

CORE CONCEPT FOR NANOFABRICATION Deposition

Template

EtchingMask

NanoporousMembrane

Remove polymerblock within cylinders(expose and develop)

Versatile, self-assembling, nanoscale lithographic system

(physical orelectrochemical)

UMass Amherst/ UC Berkeley MIT

MIT

UW Madison

Directed self-assembly for nanoscale patterning down to 3 nm

Block "A" Block "B"

Advances in the Last Decade: Patterning Approaches & Device Integration

Block copolymer lithography:A hierarchical-friendly methodBlock copolymer lithography:A hierarchical-friendly method

S. Park, et al. Science 2009. 323, 1030. I. Bita, et al. Science. 2008. 321, 939.

Y.S. Jung, et al. Nano Lett. 2010. 10, 1000. K. Galatsis, et al. Adv. Mater. 2010. 22, 769.

Scanning probe-based lithographies

Nanoimprint lithography

Many approaches for controlling the position of materials on surfaces have been developed in the

last decade.

Many approaches for controlling the position of materials on surfaces have been developed in the

last decade.

Microcontact printing

Inkjet printing

Nie, Z et al. Nature Nanotech. 2008. 7, 277.

Advances in the Last Decade: Patterning Approaches & Device Integration

U. Texas Austin Korea/Japan/Singapore Collaboration

graphene on copper

Major Advances in the Last Decade: Advanced Manufacturing

Roll-to-roll production of graphene for transparent conducting electrodesRoll-to-roll production of graphene for transparent conducting electrodes

X. Li, et al. Science 2009. 324, 1312 S. Bae, et al. Nature Nanotech. 2010. 5, 574. Replaces indium tin oxide

NanoMFGProcessesMaterials

Metrology

Workforce

EHS

Information

Tools

Education

Standards Economic

Nanomanufacturing Enterprise

(Science-based)

To create nanomanufacturing excellence, we must attend to all parts of the value chain.

Important Strides in Nano Environmental, Health, and Safety (EHS)

NIOSH: "Approaches to Safe Nanotechnology" - Emphasizing effective control banding- Now an ISO standard

NIH: Nano Health Enterprise InitiativeDuPont/EDF: Nano Risk FrameworkACS: Lab Safety Guidelines For Handling NanomaterialsLockheed-Martin: Enterprise-wide Procedure for Environmental, Safety and Health Management of Nanomaterials

Standards: Many ISO standards on EHS are being developed

NSF Centers Dedicated to Nano EHS• University of California Center for the Environmental Implications of NanoTechnology• Duke Center for the Environmental Implications of NanoTechnology (CEINT)• Rice University Center for Biological and Environmental Nanotechnology• Components within other centers (including at UMass)

Other Federal EHS Activities• National Institute for Environmental Health Science• NIH Nanomaterials Characterization Laboratory• NIOSH• EPA• FDA

Industrial EHS Testing

An open access network for the advancement of nanomanufacturing R&D and education

– Cooperative activities (real-space)

– Informatics (cyber-space)

Mission: A catalyst -- to support and develop communities of practice in nanomanufacturing.

www.nanomanufacturing.org

"Nanoinformatics"

• Nanotechnology meets Information Technology

• The development of effective mechanisms for collecting, sharing, visualizing, modeling and analyzing data and information relevant to the nanoscale science and engineering community. Nanoinformatics 2020

Roadmap publication

• The utilization of information and communication technologies that help to launch and support efficient communities of practice.

Available from internano.org

Nano-informatics: Some Major Nanotech Research Communities

Nanomanufacturing

Environmental,Health & Safety

FundamentalResearch

SocietalImpact

Modeling & Simulation

NationalInfrastructure

Health & Life Sciences

Metrology

Commercialization

Education

Energy

Materials

Nanoinformatics for Nanomanufacturing