This document discusses several types of smart materials: shape memory alloys that change shape in response to temperature changes; smart gels that expand or contract due to stimuli like light, pH, or temperature; rheological materials that change state in response to stimuli like magnetic or electric fields; magnetostrictive materials that change shape with magnetic fields; and fullerenes like buckyballs that have potential applications in superconductors, medicine, and inhibiting HIV. These smart materials have applications in areas like aeronautics, medicine, bioengineering, damping vibrations, fuel injection systems, drug delivery, and trapping atoms or molecules.

1. Smart Materials
Physics 87N
Elaine Zelby
Kevin Bird
Amit Patel
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2. 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.

3. 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.

4. Example of SMA

5. 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

6. 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.

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

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

9. 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)

10. Example of Magnetic Field on
Rheological Material

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

12. 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

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

14. 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

15. 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.