Miscibility of Crystalline Phase in Ferroelectric Blend of Vinylidene Fluoride/trifluoroethylene Copolymer

Ferroelectric blends of vinylidene fluoride（VDF）/ trifluoroethylene（TrFE）copolymer with different molar ratio of 56/44，60/40，63/37，67/33，70/30，73/27 and 77/23 were fabricated by casting from methyl ethyl ketone solution. Wide angle X-ray diffraction shows two peaks（17. 6o and 19. 5o）for all blends and copolymers，associating with amorphous region and（110）（200）reflections，respectively. It indicates that blending does not introduce any new crystal lattice. Analysis of differential scanning calorimetry（DSC）presents that the blends display the phase transition characters of both copolymers of 77/23 and 56/44. The blend components are immiscible in the crystalline phase. Thermally stimulated depolarization current of the blends exhibits the characters of both components at different polarization temperatures. In accordance with DSC results，it also proves that the crystalline phases of 56/44 and 77/23 are just independent. In addition，it is also proved that the space charge can stabilize the remnant polarization to some extent.