Voltage-strain characteristics of cylindrical polymer actuators

Cylindrical types of polymer specimens was fabricated and subjected to constant and pulse voltage with some rise time to obtain response characteristics. Quasi-steady-state stretch is almost proportional to the square of applied voltage. Strain is 2 to 3 % under the electric field of 12 V/mu m. About 40 mu m or 0.4 % was stretched in 0.5 sec under 6 kV or 12 V/mu m. A big gap in strain between quasi-steady state and dynamic response indicates that some rheological process is involved in operation mechanism to make Hook's law invalid for polymers. New polymer materials with higher permittivity and reasonable Young's modulus are awaited for actuators in reality.