Enhanced electromechanical properties in all-polymer percolative composites

In this letter, we discuss the enhanced electrostriction and dielectric constant in an all-polymer percolative composite consisting of poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] terpolymer matrix and polyaniline (PANI) conductive particles. Using a self-consistent approach, we calculate the dielectric constant and dielectric loss tangent of the composite in excellent agreement with experiments, and demonstrate that the electrostriction enhancement is due to the electric field fluctuation in P(VDF-TrFE-CTFE) matrix, which becomes dominant when the dielectric constant of the second phase is much larger than that of the matrix. The inhomogeneous field distribution in the matrix has also been used to estimate the breakdown field of the composite, which agrees well with experimental measurement. The study could be used to design and optimize electrostrictive composites with optimal electromechanical properties. (C) 2004 American Institute of Physics.