The poling of multiple-layer polyvinylidene fluoride films and their piezoelectricities

Poling of multiple-layer polyvinylidene fluoride films has been carried out. The piezoelectric properties of the poled films have been measured. It is found that the polarization is not uniform in the direction of the film thickness and that poling of multiple-layer films at elevated temperatures and lower fields often leads to results that show that at least one layer has strong piezoelectric properties. The poling mechanism is also discussed.>