Ferroelectric phase transition in a copolymer of vinylidene fluoride and trifluoroethylene

Abstract

The phase transition in a copolymer of 55% vinylidene fluoride and 45% trifluoroethylene near 70°C has been investigated by measuring the temperature dependence of fundamental properties. The remanent polarization disappeared near 70°C. The dielectric relaxation strength showed a peak indicating an anomaly and the dielectric relaxation time showed a critical slowing down phenomenon. A change in crystal lattice spacing associated with remanent strain and an anomalous specific heat were observed. These results are consistent with a ferroelectric phase transition. Comparison is made between observation and prediction by phenomenological and simple dipolar theories for a order-disorder type transition.