Ferroelectric hysteresis in simultaneously stretched and corona-poled PVDF films

Abstract

SSCP (simultaneous stretching and corona poling) of PVDF (polyvinylidene fluoride) films has enhanced the ferroelectric properties. D-E hysteresis loops of these films were observed by using the Sawyer-Tower method in the field range 35 to 80 MV/m. The dependence of ferroelectric hysteresis on poling field has also been studied. The average value of remanent polarization /spl ap/82 mC/m/sup 2/ was observed for the SSCP (simultaneous stretching and corona poling) films, which is significantly higher than the value P/spl ap/62 mC/m/sup 2/ observed for the STCP (stretched and then corona poled) films. Coercive fields of E/sub c//spl ap/61 and 50 MV/m were obtained for the SSCP and the STCP films respectively. A comparison of the IR spectra of the SSCP and the STCP films in perpendicularly polarized light E/sub /spl perp// indicates that the dipolar orientation is better in the SSCP films.