Melt-solidified and cast films of P(VDF-TrFE) copolymers: a comparison study

Structural and electrical properties of poly(vinylidene fluoride-trifluorethylene)P(VDF-TrFE) films, obtained either from casting a solution or by compression moulding from a molten phase, have been reported in a number of studies. Even though results may differ to a considerable extent when samples are prepared with different methods, few studies address these differences whose origins may lie in distinct thermal treatments. In the present study we undertake a careful comparison of experimental DSC and FTIR results on 60/40, 70/30 and 80/20 P(VDF-TrFE) copolymer samples, fabricated using these two methods. The DSC results for the 60/40 and 70/30 copolymer show two phase transitions, with the samples behaving as a paraelectric material only after the 2nd transition. It is shown that the main differences between melt-solidified and cast films arise from the thermal treatment suffered by the former samples.