Transcript Defnyddiau Craff

Additional Science
Chapter 9
Smart Materials
CHEMISTRY 2
Smart materials are new materials with properties that change reversibly
with a change in the material’s surroundings e.g. mechanical deformation
and changes in temperature, light and pH.
Additional Science
Chapter 8
Name of Smart
Material
Explanation
Use
Shape memory
polymers
These are somewhere between
thermoplastics and thermosets. When
heated the polymer softens and it can be
stretched and deformed. On cooling it
remains in the deformed state. On being
reheated it ‘remembers’ and returns to its
original shape.
Plastic car bodies from which a dent could
be removed by heating.
Medical sutures that will automatically
adjust to the correct tension and be
biodegradable, not having to be surgically
removed.
Thermochromic paints
and pigments
Organic molecules in ink and paint that
change colour as a result of temperature
change.
Print on T-Shirts that change colour with
temperature.
Mugs whose colour indicates the
temperature of the liquid inside.
Photochromic paints
and pigments
Organic molecules in ink and paint that
change colour as a result of light (especially
UV). The light breaks bonds and the atoms
are rearranged to form molecules of
different colour.
Sunglasses which react to changing light
intensity.
Maybe photochromic molecules will be
used to store data in 3D form in future.
Shape-memory alloys
Some alloys, in particular some nickel/
titanium and copper/ aluminium/ nickel
have two remarkable properties – pseudoelasticity (appearing to be elastic) and
shape-retention memory.
Spectacle frames.
Surgical plates for joining bone fractures
and surgical wires to replace damaged
tendons.
Hydrogels
Cross linked polymers that have the ability
to absorb or expel water when subjected to
certain stimuli e.g. change in temperature
or pH.
Artificial muscles and robotic actuators.