11) Smart materials

Question 1

Define smart materials

Answer 1

Materials whose physical properties change in response to an input or change in the environment such as electricity, pressure, temperature or light.

Question 2

Define an SMA, how does it work and uses

Answer 2

SMA = Shape memory alloy e.g. nitinol
Changes in response to a change in temperature or electrical input
Dental braces, bioengineering such as stents, bone plates and screws

Question 3

Define thermochromic pigments, how do they work and uses

Answer 3

Changes colour in response to temperature

Room thermometers, medical thermometers for children, ducks in baths, baby feeding spoons…

Question 4

Define phosphorescent pigments, how do they work and uses

Answer 4

Absorbs light energy during the day and ‘re-emits’ the light energy when it is dark.
Fire exit signs, glow-in-the-dark products, watch hands

Question 5

Define photochromic pigments, how do they work and uses

Answer 5

Changes colour with light intensity

Welding goggles, reactive glasses lenses…

Question 6

Define electroluminescent wire, how does it work and uses

Answer 6

Thin copper wire coated in a phosphorescent material that glows in response to an AC
Glow bracelets, interviewing for clothing, home decoration…

Question 7

Define piezoelectric material, how does it work and uses

Answer 7

Gives off a small electrical charge when deformed
Increases in size (up to 4%) when an electrical current is passed through it.
Air bag sensors in cars, BBQ lighters, stylus’ on modern gramophones, pressure sensors, musical greetings cards