Studies of Chain Conformation above the Curie Point in a Vinylidene Fluoride/Trifluoroethylene Random Copolymer

A 60/40 mol % vinylidene fluoride/trifluoroethylene random copolymer was found to undergo a ferroelectric-to-paraelectric phase transition over a broad temperature region centered at ~70 °C. This Curie transition was studied by thermal analysis, X-ray diffraction, and Raman scattering measurements. It was found that the initial trans planar conformation of the copolymer transforms into a structure similar to the TGTG’ conformation of PVF2. Raman studies have shown that the structure of the copolymer undergoes a hysteresis as it returns to its room-temperature conformation when the temperature is lowered through the Curie point. The mechanism of this transition and possible origins of the hysteresis are discussed. © 1986, American Chemical Society. All rights reserved.