Researchers the Georgia Institute of Technology have developed a device that can harness the friction between surfaces to produce electricity using the piezoelectric effect.

The piezoelectric effect is a change that accumulates in certain materials when placed under pressure. Materials displaying the piezoelectric effect can harvest the energy of motion – such as the tread of walking people or the rolling motion of a car.

Georgia Tech calls their device a triboelectric generator and it is based on flexible polymer materials. The generator operates when a sheet of polyester rubs against a sheet made of polydimethysiloxane.

It was previously observed that the friction of these two materials generate a charge, but Zhong Lin Wang of the School of Materials Science and Engineering and his team increased the current produced by using micro-patterned surfaces.

They worked with different types of surface patterning to increase the friction of the two polymers: lines, cubes and pyramids. They found that pyramid shapes generated the most electrical current, as much as 18 volts at about 0.13 microamps per square centimeter.

While the generators are small, they are also robust, continuing to produce current even after days of use. They are also nearly transparent, a trait which the scientists believe could make them ideal for use in touch screen devices to supplement the power of the devices battery if not power the entire thing.

"Friction is everywhere, so this principle could be used in a lot of applications," said Mr. Wang. – EcoSeed Staff