The artificial muscles of existing soft robots generally use hydraulic and pneumatic actuators that do not differ in speed. Elastomers - soft materials with dielectric properties can become an alternative to them.
Researchers at Harvard University's School of Engineering and Applied Sciences have developed a wide range of motion dielectric elastomer, requiring little energy and no rigid components.
Two materials were used to create the dielectric elastomer - a flexible elastomer developed at the University of California, and a carbon nanotube electrode from Clark's laboratory. Their combination allowed to create a new device with better characteristics than existing flexible drives.
Most dielectric elastomers have a limited range of motion and must be pre-stretched and attached to a rigid base. The new elastomer does not need to be pre-stretched.
To create it, a special liquid is used, which, under the influence of ultraviolet radiation, turns into thin paper sheets with a sticky coating on both sides, which allows them to be glued to each other. The result is a sandwich material consisting of layers of elastomer and electrodes.
Dielectric elastomers need to be energized to drive them. Its value depends on the thickness of the material. The more layers, the more force the material produces.
The resulting flexible actuators can be used in wearable devices to create soft grips, surgical instruments, soft robots, and artificial muscles.