Smart Materials (1) Flashcards
To be classed as a smart material what does a material have to exhibit ?
A physical change in response to an external stimuli
What are shape memory alloys (SMA) ?
Metal alloys that can remember their shape when heated
What are SMA’s often used/ utilized for ?
On spectacle frames that spring back to shape if they are squashed
What is the most notable example of an SMA that has a different property to most metals ?
Nickel titanium (nitinol)
It contracts when heated whereas most metals would expand
When braces are made from nitinol they heat up in the mouth and ‘pull’ the teeth
What is thermochromic pigment/‘s ?
A temperature sensitive pigment that changes colour when heated
‘Thermo’ relates to heat
‘Chroma’ meaning Colour
So they change color when heated
What are thermochromic often mixed with and what is this often used on ?
Paint or polymers to give the materials the same color changing properties as the pigment
Mugs or bath items for children
What are photochromic pigments ?
Pigments that work in a similar way to thermochromic pigments but ‘photo’ refers to light so they change their properties when exposed to UV light
What is a well known example of photochromic pigments ?
Lenses in glasses
When in buildings the lenses are clear, but when worn outside they become more like sunglasses when exposed to brighter light
Also used in windows to prevent rooms from getting to hot in summer
What are the benefits from photochromic pigments in glasses ?
- protecting the persons eyes from harmful UV light
- saving money as they don’t need two pairs of glasses
Yaqsimach great success 👍
