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/μm. About 40 μm or 0.4 % was stretched in 0.5 sec under 6 kV or 12 V/μm. 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.