Smart Materials Flashcards
Materials
What are smart materials?
A material whose physical properties change in response to a stimulus.
E.g. electricity, pressure, temperature, light.
Materials include; electroluminescent wire, shape memory alloys (SMA), thermochromatic pigment, thermochromatic film.
Why is thermochromic film suitable for thermometers?
-colour change makes it easier to read than small numbers on traditional thermometers (e.g. goes red for hot).
-non-toxic material so is safer to use than mercury thermometers especially when being used for children.
-can be incorporated into a film strip, making it flexible enough to go on forehead.
What is a transition temperature?
When a SMA is heated to this temperature, it returns to its original shape.
The transition temperature can be set at various levels depending on the product.
How does thermochromic pigment work?
It changes colour in response to temperature change.
e.g. thermometers
How does phosphorescent pigment work?
Absorbs light energy during the day and re-emits the light when its dark.
e.g. glow in the dark products
How does photochromic pigment work?
changes colour with light intensity.
e.g. lenses in glasses that change to sunglasses.
How does electroluminescent wire work?
its a thin copper wire that is coated in a phosphorescent (absorbs in light, emits in dark) material. It glows in response to an AC (alternating current).
How does piezoelectric material work?
When pressure is applied to this material, the electrical charges become imbalanced. A metal plate collects the charges and these generate/send a current.
Uses: watches (movement of hands), gas lighters (spark).
How could Shape Memory Alloys/Polymers help in disassembly?
Some SMAs and SMPs (Shape Memory Polymers) hold together elements of products like phones.
At the end of their life, phones would be put into disassembly ovens that reach the transition temperature, and the product automatically disassembles.
This method hasn’t been taken up by manufacturers yet.
