Smart Materials ( New Technologies And The Creation Of New Materials )

Question 1

Smart materials

Answer 1

• respond to environmental stimuli with particular changes in some variables.
• also called material responsive materials.
• depending on changes in some external conditions smart materials change their properties (mechanical, electrical, appearance), their structure or composition or their functions.

Question 2

Conditions for smart materials to change

Answer 2

Electricity
Pressure
Moisture
Heat
Light

Question 3

Thermo ceramics

Answer 3

• very hard internal structure
• stable at high temperatures
• produced by combining ceramic and metallic powders by sintering.
• used in specialist engineering situations eg turbine blades in jet engines
• very brittle and expensive

Question 4

Photochromic

Answer 4

• Greek, meaning light and coloured
  Used in:
  Photochromic glass (tinted, impregnated with silver halide)
  Children’s swim suits (turns a different colour with UV)
  High security documents

Question 5

Thermo chromic

Answer 5

• Greek means heat, coloured
  Uses:
  Test panels on battery packaging
  Thermometers
  Built in ink polymers
  Special printing effects for promotional panels (eg mood ring)

Question 6

Polymorph

Answer 6

Greek, many and change
- developed to be used as a modelling material.
- can be shaped by heating in water to a temperature of 60oc
- Non toxic material that is fully biodegradable.

Question 7

Solar panels

Answer 7

• harness sun through photovoltaic cells
• thin layers of silicon
• used where power is not readily available

Question 8

Shape memory alloys

Answer 8

• can be deformed by outside stimulus
• reverts back to original once stimulus removed
• nitinol is programmed to maintain a particular length or shape at a set temperature.

Used in: hot water systems, central heating, fire alarms.
Green houses, when too hot nitinol in window stays open the window and closes when cooled down.

Question 9

QTC definition

Answer 9

flexible polymer which contains tiny metal particles, normally an insulator but when squeezed conducts.

Question 10

quantum tunnelling composites

Answer 10

• can be moulded into virtually any size, thickness or shape.
• durable, no moving parts to wear out.
• mechanically strong
• can be made to withstand extreme temperatures.
• versatile, both electrically and physically (range of sensitivity can be altered).
• intrinsically safe, contactless switch (ideal for a spark free operation).
• can be directly interfaced to standard electronic and electrical devices.
• wire free