Characterization and ferroelectric properties of electric poled PVDF films

The electric poling behaviors of poly(vinylidene fluoride) (PVDF) thin films prepared by solution-casting method were characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM). The ferroelectric properties of PVDF films were also investigated. The present study gives an immediate evidence of a progressive phase transition taking place in PVDF films during electric poling. The phase transitions are characterized as α phase to β phase via middle δ phase with increment of poled electric field intensity. According to ferroelectric hysteresis performance of PVDF films, it can be found that the trend of remnant polarization P_r which increases with the poled electric field intensity is coincident with Boltzmann distributing function. And the results indicate that the range of the poled electric field intensity which brings about the maximal remnant polarization P_r was 105-125 MV/m, the P_r could be as high as 6 μC/cm².