Smart materials

• Known as intelligent or responsive materials.

• Can change their properties in a controlled way in response to external stimuli.

Examples:

• Thermochromic pigments: changes color when heated.

  -Usually used in mugs, spoons, thermometers and battery power indicators.

• Photochromic pigments: change color when exposed to light.

  - Used in glasses that darken in sunlight.

• Shape memory alloys: Can remember their shape when heated.

  -Used in spectacle frames that spring back to shape if they are squashed.

• Nickel titanium: a shape memory alloy that contracts when heated or exposed to an electrical current,

  -Used in braces.

• Piezoelectric materials: can convert mechanical energy into electrical energy.

  -Used in mobile phones speakers, gas lighters, quartz clock and inkjet printers.

• Electroactive paper: A rediscovered bioplymer that can be used in various applications.

- used in artificial muscles and biomimetic robots.