Thin material generates electricity when stretched
Made from a
specially designed rubber, it could lead to smart clothing or skin for robots
that can feel touches
Scientists have developed a thin, flexible material that
generates electricity when stretched or compressed, an advance that may pave
the way for smart clothing or self-powered pacemakers.
The specially designed rubber, developed by researchers at Swiss
Federal Laboratories for Materials Science and Technology (Empa) is able to
convert mechanical movements into electrical charges.
The trick behind the generated current is the internal
polarisation which changes when the rubber film is mechanically stressed,
scientists said.
This effect is used in sound pick-ups on analogue record
players, for instance: the needle is guided through the grooves in the record
in such a way as to generate mechanical vibrations.
In a piezoelectric crystal, these vibrations are converted into
electrical impulses, which can be amplified and transformed into sound waves.
For a long time, the piezoelectric effect was only known for
crystals. As these are heavy and solid, the effect could only be used in
certain applications.
However, researchers have now succeeded in giving elastomers
piezoelectric properties. Nevertheless, the new material is not easy to
produce.
The rubber is a composite material made of polar nanoparticles
and an elastomer – silicone in the prototype.
There is a wealth of potential applications for the novel rubber
film. It could be used to construct pressure sensors, for example. If the
material is compressed, an electrical impulse is produced that can be received
and “understood” by devices.
This can be used to develop a novel type of control buttons, but
also a sensitive skin for robots that can feel (pressure) touches. Moreover,
the film might be useful in clothing to either monitor the wearer's activities
or generate electricity from their movements.
“This material could probably even be used to obtain energy from
the human body,” said Dorina Opris researcher at Empa.
“You could implant it near the heart to generate electricity
from the heartbeat, for instance,” Opris said.
MM 13NOV17
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