Defect induced mechanisms in the ferroelectric-to-paraelectric phase transition of poly(vinylidene fluoride-trifluorethylene) copolymers

X-ray techniques have been used to study the ferroelectric-to-paraelectric phase transition in poly(vinylidene fluoride-trifluoroethylene) copolymers. Thermal cycles for copolymers with 20 to 40 mol.% trifluoroethylene are presented. A partial hysteresis cycle has been obtained for the 25 mol.% trifluoroethylene sample. Clear evidence of anchoring and memory effects has been demonstrated. It appears that defects play a very important role in the mechanism of the transition. At least some of them are mobile and can relax