FERROELECTRIC HYSTERESIS IN SIMULTANEOUSLY STRETCHED AND CORONA-POLEDPVDF FILMS

SSCP (simultaneous stretching and corona poling) of PVDF (polyvinylide ne fluoride) films has enhanced the ferroelectric properties. D-E hyst eresis loops of these films were observed by using the Sawyer-Tower me thod in the field range 35 to 80 MV/m. The dependence of ferroelectric hysteresis on poling field has also been studied. The average value o f remanent polarization approximate to 82 mC/m(2) was observed for the SSCP (simultaneous stretching and corona poling) films, which is sign ificantly higher than the value P approximate to 62 mC/m(2) observed f or the STCP (stretched and then corona poled) films. Coercive fields o f E-c approximate to 61 and 50 MV/m were obtained for the SSCP and the STCP films respectively. A comparison of the rn spectra of the sscp a nd the step films in perpendicularly polarized light E-perpendicular t o indicates that the dipolar orientation is better in the SSCP films.