Novel electrostrictive poly(vinylidene fluoride-trifluoroethylene) copolymer actuators

Abstract

Electroactive materials for applications in active noise and vibration control should possess a high displacement capability, high reliability, and be easily fabricated to conform to complicated surfaces and shapes. Apparently, almost all the current available materials cannot meet these requirements. It was discovered recently that a massive electrostriction (strain level ∼5%) can be achieved in specially treated P(VDF-TrFE) copolymers [Q. M. Zhang, Vivek Bharti, and X. Zhao, Science 280, 2101 (1998)]. More significantly, because of the high elastic modulus, the material also exhibits high elastic energy and power density, an order of magnitude higher than those from the conventional piezoceramic and magnetostrictive materials. In addition to the large longitudinal strain, the transverse strain can be tuned over a broad range by varying the processing and irradiation conditions, from near zero in unstretched samples to more than the longitudinal strain in stretched samples. In this paper, the electromechanical properties of this class of material and the performance under different external conditions will be presented. The results on the unimorph and multilayer actuator performance fabricated using the new electrostrictive polymers with different electrode materials will also be presented. [Work supported by ONR.]