Dielectric measurements and X-ray investigations on the phase transitions of poly (vinylidene fluoride-hexafluoropropylene) copolymers

Paraelectric-to-ferroelectric phase transition has been observed under low electrical stresses in vinylidenefluoride-hexafluoropropylene (VDF-HFP) copolymers with 15% HFP molar content. This phase transition, detected by thermodepolarization processes and differential scanning calorimetry techniques, is confirmed in the present work by X-ray and dielectric measurements. These results showed the structural evolution of the copolymer from the alpha nonpolar to the delta polar configuration under electrical stress of 0.5 MV/cm.<
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