Transcript Nanotechnology Impact

Nano-Impact
Jonathan P. Rothstein1 and Mark Tuominen2
1. Mechanical
Engineering Dept.
Mechanicaland
andIndustrial
Industrial Engineering
2. PhysicsUniversity
Dept. of Massachusetts
MA, USA
University of Amherst,
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?
Kevlar
Kevlar & Nanoparticle Suspension
Lee, Wetzel and Wagner J. Material Science (2003)
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.
1000
Viscosity [pa.s]
•
100
10
1
0.1
1
10
100
-1
Shear Rate [s ]
Increasing
Stretch Rate
1000
Why Size Matters
1mm Particles
100nm Particles
10nm Particles
• 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.
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.
Water Drops on a Lotus Leaf
•
The surface of the lotus leaf has 10mm 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.
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
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
Experiment:
• Place a small drop of water on the
smooth Teflon surface.
• Tilt the surface through vertical.
• Does the drop stick or slide?
Sanded Teflon
• 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.
d
•
Currently capable of reducing drag by over 70% in
both laminar and turbulent flows!
Hierarchical Nanostructures
On Silicon
w
On PDMS
15μm
Can These Surfaces Have a Real Impact?
• 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
60μm
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.
p  pw  pa 
•
4 cos(  a )
w
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.
Coating
Module
Supply
Drive
Module
Imprinting
Module
Receive
Drive
Module
Why Roll-to-Roll Nanoimprint Lithography
Membranes
and Filters
Coating
Module
Supply
Drive
Module
•
•
•
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.
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 National
Nanotechnology Initiative for 2011
1.
2.
3.
4.
5.
6.
7.
8.
Fundamental nanoscale phenomena and processes
Nanomaterials
Nanoscale devices and systems
Instrumentation research, metrology, and standards
Nanomanufacturing
Major research facilities and instrumentation
Environment, health and safety
Education and societal dimensions
484M
342M
402M
77M
101M
203M
117M
35M
"Nano2" Report
http://www.wtec.org/nano2/
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
Entropic Drying Effects
Electrostatic Assembly
Shevchenko, E. V. et al. Nature 2006. 439, 55.
Kalsin, A. M. et al. Science 2006. 312, 420.
Directed 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 “B”
PS
Block “A”
PMMA
~10 nm
Scale set by molecular size
Ordered Phases
10% A
30% A
50% A
70% A
90% A
CORE CONCEPT
FOR NANOFABRICATION
Deposition
Template
(physical or
electrochemical)
Etching
Mask
Remove polymer
block within cylinders
(expose and develop)
Nanoporous
Membrane
Versatile, self-assembling, nanoscale lithographic system
Advances in the Last Decade: Patterning
Approaches & Device Integration
Block "A"
Block "B"
UMass Amherst/ UC Berkeley
Block copolymer lithography:
A hierarchical-friendly method
MIT
UW Madison
Directed self-assembly for nanoscale
patterning down to 3 nm
MIT
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.
Advances in the Last Decade: Patterning
Approaches & Device Integration
Scanning probe-based
lithographies
Many approaches for controlling the position of
materials on surfaces have been developed in the
last decade.
Microcontact printing
Nanoimprint lithography
Inkjet printing
Nie, Z et al. Nature Nanotech. 2008. 7, 277.
Major Advances in the Last Decade:
Advanced Manufacturing
Roll-to-roll production of graphene for transparent conducting
electrodes
graphene on copper
U. Texas Austin
X. Li, et al. Science 2009. 324, 1312
S. Bae, et al. Nature Nanotech. 2010. 5, 574.
Korea/Japan/Singapore Collaboration
Replaces indium tin oxide
Nanomanufacturing Enterprise
Workforce
Tools
Metrology
Materials
EHS
NanoMFG
Processes
Information
(Science-based)
Standards
Economic
Education
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 Initiative
DuPont/EDF: Nano Risk Framework
ACS: Lab Safety Guidelines For Handling Nanomaterials
Lockheed-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
Modeling &
Simulation
Health &
Life Sciences
Materials
Fundamental
Research
Nanomanufacturing
Education
Environmental,
Health & Safety
Societal
Impact
National
Infrastructure
Commercialization
Metrology
Energy
Nanoinformatics for Nanomanufacturing