"The researchers built on ‘dielectric elastomer generator’ technology that used the movements of a flexible, non-conductive material to build up charge in attached electrodes."
These Artifical Muscles are electroactive structures consisting of two layers of conducting carbon grease separated by an extremely stretchy insulating polymer film.
"When a voltage is applied, the configuration behaves like a capacitor, with positive and negative charges accumulating on either side of the insulator. As the opposite charges attract one another the insulator is squashed between them and flattens and stretches. Turn the voltage off and it contracts again to its original size." says New Scientist
