Smart Materials

Shape memory alloy:

SMA's return to their original shape when heat is applied

Advantages	Disadvantages
Good mechanical properties Flexible Lightweight Durable	Expensive Can be overstressed Poor fatigue properties Difficult to repair

Uses: Braces, spectacles, planes, tweezers

Reactive glass:

Reactive glass goes from transparent to opaque when a current is passed through it

Advantages	Disadvantages
Multi-use Provides shade from harmful UV rays Can eliminate need for blinds/curtains in house Allows control of natural light levels Can be used as energy saving windows	Needs an external stimulus to work

Uses: Glass panels in buildings, privacy glass, auto-dimming rear-view mirrors

Photo-chromic materials:

change colours depending on light conditions (e.g. classes that also act as sunglasses)

Advantages	Disadvantages
Multiple uses Reacts to environment Reversible reaction	Expensive Sometimes doesn't fully react

Uses: Sunglasses, security sensors, UV light warning sensor, welding masks

Thermo-chromic materials:

change colours depending on temperature conditions

Advantages	Disadvantages
Multiple uses Reacts to environment Broad range of colours	Expensive Sometimes doesn't fully react Hard to make Takes time to fully react

Uses: Baby spoons, coffee mugs, batterys (charged or not)

Quantum tunnelling composites:

conduct electricity when pressure is applied

Advantages	Disadvantages
Good electrical insulator and conductor Flexible Durable Lightweight Water resistant	Relatively unknown technology Expensive Hard to manufacture

Uses: Power tool switches, robots, clothing/fabrics

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