Smart Materials

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Smart Materials

• Physics 87N
• Elaine Zelby
• Kevin Bird
• Amit Patel
• ?

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What is a Smart Material?

• Basically its a material that reacts quickly to
  a stimulus in a specific manner.
• The change in the material can also be
  reversible, as a change in stimulus can bring the
  material back to its previous state.

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Shape Memory Alloys (SMAs)

• Metals that exhibit pseudo-elasticity and the
  Shape Memory Effect
• The basic principle behind SMAs is that a solid
  state phase change occurs in these materials.
• They switch between states of Austenite and
  Martensite.

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Example of SMA
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Appplications of SMAs

• Popular SMAs are NiTi, CuZnAl, and CuAlNi
• Applications include
• Aeronautical
• Making flexible wings using shape memory wires
• Medicine
• Bone plates made of NiTi
• Bioengineering
• Muscle wires that can mimic human movement

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Smart Gels

• A smart gel is a material that expands or
  contracts in response to external stimuli.
• A smart gel consists of fluid that exists in a
  matrix of polymer(s).
• Stimulus can include
• Light
• Magnetic
• pH
• Temperature
• Electrical
• Mechanical
• Stimulus will alter the polymer that makes it
  more or less hydrophillic.

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Tanaka experiment
Modeled after T. Tanaka, Science 19 November
1999 Vol. 286. no. 5444, pp. 1543 - 1545
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Applications of Smart Gels

• Medical
• Drug release
• Organ replacement
• Muscle replication
• Industrial
• Shake gels
• Shock absorbers

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Rheological Materials

• Material that can change its physical state very
  quickly in response to a stimulus
• Stimulus include
• Electrical
• Magnetic
• Ferromagnets
• Magnetic field aligns ferromagnetic molecules in
  order in order to achieve solid state structure
• Nanoparticles reduce IUT effect (In Use
  Thickening)

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Example of Magnetic Field on Rheological Material
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Applications of Rheological Materials

• MR materials
• Structural Support
• Dampers to minimize vibrational shock from wind
  and seismic activity.
• Industrial
• Break fluids
• Shock absorbers

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Magnetostrictive materials

• Material that stretches or shrinks when a
  magnetic field is applied.
• Conversely, when a mechanical force is applied on
  the material, a magnetic field is induced.
• Ferromagnets
• Magnetic field can be used to create an electric
  current

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Applications of Magnetorestrictive Materials

• More efficient fuel injection system
• Specific amounts of fuel
• Higher frequency

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Fullerenes

• A fullerene is any series of hollow carbon
  molecules that form either a closed cage, as in a
  buckyball, or a cylinder, like a carbon nanotube.
  
• Most researched/utilized fullerene is the
  carbon-60 molecule (truncated icosaheedron)
• Three nanotubes can be made by varying the chiral
  angle.
• Arm-chair
• Zig-zag
• Chiral
• Chiral angle determines conductivity

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Applications of fullerenes

• Superconductors
• By doping fullerenes with three variable atoms, a
  superconducting state can be achieved.
• Medical
• Atoms can be trapped in a buckyball, in order to
  create a biological sponge.
• HIV protease inhibitor
• A buckyball can be inserted in the HIV protease
  active site in order to stop replication.