Smart Materials Flashcards
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
● UV Light
What are Thermochromic pigments?
● These pigments/inks/dyes react to heat by changing colour at specific temperatures
● You can get irreversible versions of the pigment which can be used to indicate that a critical temperature has been met.
● Uses: Room thermometers Flexible thermometers Children’s cutlery
What are Phosphorescent materials?
● Phosphorescence is a process whereby energy from the sun is absorbed by a ‘material’ and it is released slowly over a long time, in the form of light.
● The energy / light emitted is at a low intensity and this can last for many hours.
● Uses: glow-in-the-dark toys, stickers, paint, wrist watch and clock dials
What are Piezoelectric materials?
● Generates a small electric charge when sensors are compressed.
● Can also generate movement when an electric charge is applied (actuator).
● Uses: Generating energy. Sensors-burglar alarms, keyless car entry, seat belt sensors. Actuators-digital cameras
What are Photochromic materials?
● UV light stimulates particles in a special pigment.
● Darkens/colour change when exposed to light and reverses in the dark
● The effect only lasts as long as strong UV light is present.
● Uses: Sunglasses, Plane cockpit windows, Novelty products
What are Shape memory alloys?
● Are metal alloys that can remember their shape when heated.
● If the shape of the object is changed it will return to its original shape when heat or a current is applied.
● Uses: Glasses frames Greenhouse window openers Medical stents Orthodontic wires
What are QTC (Quantum Tunnelling Composite) materials?
● This smart material can be either a conductor or insulator.
● QTC varies its electrical resistance depending on the amount of pressure or stress applied to it.
● The more pressure applied, the less resistance it has.
● Uses: Touch sensitive interactive devices (computers and mobile phones) Speed controllers Wearable technology
