Space charge and polarization in ferroelectric polymers

A method of constant current corona charging was developed by B. Gross et al. (1981) to investigate transient processes of carrier transport and space charge accumulation in polymers. In the present work, the constant current method is applied to study space charge formation and polarization build-up in typical ferroelectric polymers such as poly(vinylidene fluoride) (PVDF) and its copolymer with tetrafluoroethylene (VDF-TFE). A phenomenological model for the constant-current charging of the ferroelectric polymers is developed and found to properly describe the main features of the charging process and its three-stage nature. The most suitable sites for charge trapping are probably crystalline boundaries, where the carriers, if trapped, partly neutralize the internal depolarization field