Polarization enhancement for poly(vinylidene fluoride-trifluoroethylene) 75/25 copolymer films by interlayer ordering under cyclic electric field

We report an intriguing phenomenon of polarization enhancement for poly(vinylidene fluoride-trifluoroethylene) 75/25 mol % copolymer films under cyclic electric field. If the copolymer film is initially subjected to electric cycling at a comparatively low field magnitude, the remanent polarization (P(r)) increases with the field cycles during the subsequent electric cycling at a higher field magnitude. The morphology and microstructure change during the electric cycling are examined. It is suggested that polymer chains in the interfacial layers between the crystalline and amorphous regions gradually increase in the ordering degree and that contributes to the polarization enhancement during electric cycling. (c) 2008 American Institute of Physics.