Material Dielectric elastomers
Dielectric elastomers (also called electrostrictive polymers) exhibit a mechanical strain when subjected to an electric field. Their striction capability is much higer than that of piezoceramics (10-30% vs. 0.1-0.3%).

The most common are PMMA-based electrostrictive polymers. Thanks to their electrostrictive strain, they can be sandwiched between two electrodes to emulate the operation of muscles.

In an electric field, the elastomer expands in the plane of the electrodes, amplifying the normal compression due to the electrostatic charges on the electrodes. The result is a muscle with large strain capability, and a large actuation pressure.
Category Responsive (smart) materials, Moving materials
Processes Spin coating
Dipping
Casting
Similar materials Piezoelectric materials
Conducting polymers
Polymer gels
References SRI International
Low mass muscles actuator
Price Dielectric elastomers are still at a research level, but they have the potential to be produced at a low cost.
Additional Info By rolling a tube of a thin film with many layers, larger strains can be achieved.

After a couple of years dielectric elastomers don't show any sign of degradation.
Photo Thomas Nissen (Computer graphics)
Copyright © 1996-2003 Torben Lenau
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