smart materials

1. Smart Materials

2. What are smart materials
• Smart materials are designed materials that
have one or more properties that can be
significantly changed in a controlled fashion by
external stimuli, such as stress, temperature,
moisture, pH, electric or magnetic fields.

3. TYPES OF SMART MATERIALS
There are a number of types of smart material, some of which are
already common. Some examples are as following:
• Piezoelectric materials
• Shape-memory alloys
• Photomechanical materials
• Self-healing materials
• Thermoelectric material

4. Piezoelectric MATERIALS
• Piezoelectric materials are materials that
produce a voltage when stress is applied.
Since this effect also applies in the reverse
manner, a voltage across the sample will
produce stress within the sample. Suitably
designed structures made from these
materials can therefore be made that bend,
expand or contract when a voltage is
applied.
• Piezoelectricity is found in useful
applications such as the production and
detection of sound, generation of high
voltages, electronic frequency generation,
microbalances,., and everyday uses such
as acting as the ignition source for
cigarette lighters and push-start
propane barbecues.

5. Shape-memory polymer
• Shape-memory polymers (SMPs) are
polymeric smart materials that have the
ability to return from a deformed state
(temporary shape) to their original
(permanent) shape induced by an external
stimulus (trigger), such as temperature
change.
• One of the first conceived industrial
applications was in robotics where shape-
memory (SM) foams were used to provide
initial soft pretension in gripping. the
materials have seen widespread usage in
e.g. the building industry (foam which
expands with warmth to seal window
frames), sports wear (helmets, judo and
karate suits) and in some cases with
thermochromic additives for ease of
thermal profile observation.Polyurethane
SMPs are also applied as an autochoke
element for engines.
• In medicine it is used in orthopedic surgery

6. Photomechanical materials
• The photomechanical effect is the change in the shape of a
material when it is exposed to light. More recently, Uchino
demonstrated that a photostrictive material could be used as legs in
the construction of a miniature optically-powered "walker."
• The most common mechanism of the photomechanical effect is
light-induced heating.

7. Self-healing material
• Self-healing materials have the
intrinsic ability to repair
damage due to normal usage,
thus expanding the material's
lifetime
• Rothwell’s Best-of-the-Best
winner proposes new kind of
glass that is not only
environmentally friendly and
biocompatible, but is also self-
healing. The idea combines
chitosan and oxetane
compounds into a bioactive
glass

8. Thermoelectric materials
• Thermoelectric
materials are used to
build devices that
convert temperature
differences into
electricity and vice-
versa.