Smart Materials
Definition
Smart materials are reactive materials, whose properties can be altered by exposure to stimuli, such as electric and magnetic fields, stress, moisture and temperature. They react to environmental conditions.
'Chromic' pigments
Thermochromic Pigments
Pigments that change colour with temperature
Used in temperature gauges and colour changing spoons
Photochromic Materials
Change colour or darken, depending on light exposure
Used mainly in sunglasses and spectacles
Electrochromic materials
Change colour or opacity when a current is passed through them
Used in aircraft, car and office glass for comfort and security
Electrorheostatic and Magneto-rheostatic materials (ER + MR)
They change thickness to nearly solid, within a millisecond when exposed to an electric or magnetic field
Uses (ER)
Valves
Uses (MR)
Washing machines
Noise engine mounts
Prosthetic limbs
Polymorph
The ultimate thermoplastic
Above 62 degrees it forms a pliable, clear solid mass
It is used for handles and grips, and prototyping complex shapes
Piezoelectric Materials
Generate an electric current when pressure is applied
When an electric current is applied, the change size up to 4% in volume
Shape Memory Alloys (SMA)
When this material is bent, it can be heated to return it to its original shape
Can be used as a fire alarm trigger
Used in braces, particularly Nitinol and Memoflex
Quantum Tunnelling Composite (QTC)
A flexible polymer connecting tiny metal particles
It conducts electricity when compressed, and can be woven into fabrics
It is driving touch screen technology
Electro luminescent wire
Thin copper wire is coated in phosphor, glows with an AC current
Used in emergency lighting, Christmas lights, etc.
Nanomaterials
Structures of viruses, wax crystals and spiders
Includes magnetic, optical performance, conductivity and absorbency
Resulted in harder and tougher tools, water repellent and antibacterial coatings
Gecko feet can stick to surfaces with nano materials