Polarization reversal in vinylidene fluorride-trifluoroethylene copolymer wrth intermediate comonomer content

Abstract

In copolymers of vinylidene fluoride (VDF) and trifluorcx (TrFE) with intermediate and high TrFE content the polarization takes place in a double step manner characterized by high i electric fields Eh and El corresponding to polarizati depolarization, respectively. This gives rise to a con ferroelectric hysteresis loop for the copolymers, being contras' the case of VDF rich copolymers which exhibit the sharp currenl polarization reversal at the coercive field and the hysteresis rectangular shape. The two electric fields Eh and E1 are cons influenced by temperature and hydrostatic pressure. Tempera pressure at which E1 reduces to zero are related to a transition 1 two phases S and D with slightly different structure. De< temperature and/or increasing pressure enhance the formation phase. The two fields & and E1 merge into a single coercive f i t a sufficiently high pressure. This paper presents the ferrc behavior and related structure in VDF / TrFE copolyme intermediate comonomer content.