Smart Materials Flashcards
What are modern materials
Materials that have been altered to have better properties
What are smart materials
Existing or modern materials with physical properties that can be altered by external output
E.g temperature, light, moisture
They return to their original state when the conditions change
Description / use / pros / cons
Shape memory alloys
Can be plastically deformed (stretched) and return to their original shape when heated
E.g nickel-titanium
Glasses frames
Greenhouse window openers
Orthodontic wires
P-
Lengthens product life
Reduces overall size / complexity
C-
Expensive
Continuous use can cause metal fatigue
Description / use / pros / cons
Nanomaterials
Made of tiny components less than 100nm
In the form of particles, nanowires, nanotubes or surface coatings
Sunscreen
Tennis rackets
Car bumpers
P-
Large relative surface area → improves strength elasticity magnetic elctrical thermal conductivity and absorbent properties
Can combined properties
C-
Unusual physical and chemical properties
May need specialist risk assessment, relating to health and environment
Description / use / pros / cons
Photochromic glass
Darkens when exposed to light → lightens in the dark..
Made of tiny silver halide particles that react with uv light causing a chemical reaction to change the glasses colour
Sunglasses
Plane cockpit windows
P-
Adapts easily to changing conditions
Can go thousands of cycles without performance change
C-
May be slow to react
User cannot control reaction
Description / use / pros / cons
Reactive glass
Uses electromagnetic technology to change from transparent to opaque by applying voltage while allowing light to pass through
Welding masks / goggles
Windows
P-
Retains heat so reduced energy bills
Instant privacy without permanent blocking of light
C-
Expensive
Requires electricity
Description / use / pros / cons
Piezoelectric materials
Generates a small electric charge when compressed (sensors)
Can work in reverse, generating movement when an electric current is applied (actuators)
Generating electricity
Sensors - burglar alarms
Actuators - precise position control e.g digital cameras
P-
Sustainable
Low maintenance
Compact size useful in micro-electronics
C-
Wears out
Has temperature, load and voltage limitations
Description / use / pros / cons
Temperature responsive polymers
Can change physical properties with a change in temperature, so they are useful in many scientific applications
Can deliver drugs cells or proteins to a patient when mixed with liquid polymers
P-
Useful in biomedical applications
C-
Still being researched so wider application may take time
Description / use / pros / cons
Conductive links
Contain pigments that allow small currents to flow when dry
Made with silver or other precious metals
Used in a pen on any suitable material
Drawring working circuits onto polyester
P-
Easy to use
Low waste
Ink can be folded so you can draw the circuit and fold it
C-
Silver is expensive
Difficult to get circuits right
