jacquelynn garofano crisp center for research on interface structures & phenomena nsf materials...
TRANSCRIPT
Jacquelynn Garofano • CRISPwww.crisp.yale.edu
CENTER FOR RESEARCH ON INTERFACE STRUCTURES & PHENOMENANSF Materials Research Science and Engineering Center
April 01, 2011 • Three Rivers Community College
materials sciencethe hybrid science
chem • physics • bio • nano
wings, feathers, bubbles, thin films … what do these things have in common?
Materials Science
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structure • properties • characterizationprocessing • performance
Jr Laser Camp• Three Rivers Community College • April 01, 2011
MAKING STUFF SeriesEach episode focuses on a current, overarching
aspect of materials science research
www.pbs.org/wgbh/nova/tech/making-stuff.html
Jan 19 Jan 26 Feb 02 Feb 09
STRONGER SMALLER CLEANER SMARTER
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Let’s get some perspective
The scale of things …
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Macroscale [100 to 10-3 m]
Meter [1 m = 100 m]
Centimeter [1 cm = 10-2 m] Millimeter [1 mm = 10-3 m]
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Microscale [1 μm = 10-6 m]
1 μm = one-millionth of a meter
Human hair 50 – 80 μm Red blood cells < 8 μm
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Nanoscale [1 nm = 10-9 m]
1 nm = one-billionth of a meter
Virus < 50 nm DNA = 2.5 nm thick
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Angstrom [1 Å = 10-10 m]
Atom = 0.1 – 0.3 nm
1 Å = 0.1 nm = one ten-billionth of a meter
AFM image: 48 iron (Fe) atoms in a circle onto the surface of gold (Au)
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Nanoscale Properties
What’s unique about material properties the nanoscale?
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The structure at nanoscale gives rise to properties, i.e. macroscale behavior
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Iridescence
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The wings are made up of tiny scales that are comprised of even smaller ridges that causes interference of light.
Although the shell is only a few mm thick, it’s made of ~15,000+ layers of nm thin plates of mineral.
Abalone shellBlue morpho
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Pigment v Nanostructure
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Peacock feathers
Is the color due to pigment or structure?
Jr Laser Camp• Three Rivers Community College • April 01, 2011
How can we tell?
Thin films
• The nanostructures of iridescent feathers, shells, and wings are within the UV size range (400 – 700 nm); as are thin films.
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Soap bubbles
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Iridescent colors are observed due to interference of light rays; thickness
Optical interference
CONSTRUCTIVE interference DESTRUCTIVE interference
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Thin film interference is CONSTRUCTIVE
Bulk to thin film
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thin films deposited on flexible (polymer) sheets is advantageous for artichitural design
Jr Laser Camp• Three Rivers Community College • April 01, 2011
Take Aways
• The way a material behaves on the macroscale is affected by its structure on the nanoscale
• The thin film reflects light differently depending on how thick it is, so you see different colors
• Scientists and engineers are trying to make new materials/devices with new technologies
Jr Laser Camp• Three Rivers Community College • April 01, 2011