Smart And Modern Materials Flashcards
What are smart materials?
Materials whose properties change when exposed to a stimulus such as electric, magnetic, stress, moisture and temperature
Smart textiles can be used for…
Medical such as antiseptic socks
Anti bacterial towels
Rhovyl is an antibacterial fibre
Give 3 examples of smart materials.
Conductive polymers
Colour changing liquid crystals
Motion control gels like smart grease used in CD drawers
What are photochromic materials?
Change colour due to different lighting conditions
Eg security markers which only show up in uv light
Photochromic lenses in glasses which darken in sunlight
Advantages of Photo-chromic lenses
Reduced costs as only need one pair of glasses for inside and out
Uv protection for eyes
Convenience
Eye health
What are Thermo-chromic inks?
Temp sensitive compounds that temporarily change colour when heated
uses: Can put them on kettles or mugs to show how hot they are
What can phosphorescent pigments do?
Glow in the dark
What is a composite material?
Materials made of 2 or more materials bonded together
Polymers can be strengthened by adding..
Glass, carbon fibre or Kevlar
Name the 4 wood based composites.
Plywood
MDF
Chipboard
Hardboard
What is a synthetic material?
created by man, to make completely new materials or copy natural ones
What are the properties of Kevlar?
Uses?
high resistance to impact and abrasion
made by woven fibre
used for bullet proof vests, motorbike clothing
What are the properties of Carbon Fibre?
Uses?
high strength to weight ratio
made by woven carbon fibres in a polymer resin
used for canoe shells, racing cycles
What are the properties of Goretex?
waterproof, windproof, breathable as tiny pores allow water vapour from sweat to escape but not rain water to enter
made from a PTFE polymer
outdoor clothing
What does SMA stand for and what are its properties?
Shape Memory Alloy
returns to its shape after being deformed
used for spectacle frames and teeth braces
What is Photochromic glass
changes colour when light falls on it
pigment in glass darkens in light
uses are sunglasses, welding masks
What are Piezoelectric materials?
material will deform when small electric current passes through it. Also produces a small voltage when deformed.
uses: alarms, contact sensors, strain gauges
What is Micro-encapsulation?
tiny bubbles of liquid or solid encapsulated within fabrics.
Friction as you move breaks down bubbles slowly releasing the contents (like therapy oils, moisturisers
What is a Quantum Tunnelling Composite QTC?
flexible polymer containing tiny metal particles. This can turn the insulator into a conductor. Resistance changes under compression.
Uses: pressure sensors, membrane switch on mobile phones
What are biometrics?
electronics embedded into textiles to form digital components
Uses: aesthetic or performance enhancing clothing
What are interactive fabrics?
they function as electronic devices and sensors.
- circuits integrated into fabrics (heart rate monitors)
- Wearable electronics (mobile phones or music players)
- GPS tracking
Nitinol is a shape memory alloy of nickel and which other metal?
titanium
How is the shape set into the memory of nitinol?
Heat nitinol to very high temp of around 540 degs C
What stimulus is required to return an Shape Memory Alloy like Nitinol to its original shape?
Heat to moderate temp of around 70 degs C
OR pass electrical charge through it
These trigger the response to change to set shape
