Smart Materials

What is a Smart Material? Basically it’s 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.

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.

Example of SMA

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

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.

Tanaka experiment Modeled after T. Tanaka, Science 19 November 1999: Vol. 286. no. 5444, pp. 1543 - 1545

Applications of Smart Gels Medical Drug release Organ replacement Muscle replication Industrial Shake gels Shock absorbers

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)

Example of Magnetic Field on Rheological Material

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

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

Applications of Magnetorestrictive Materials More efficient fuel injection system Specific amounts of fuel Higher frequency

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

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.