Room Temperature Poling of Poly(Vinylidene Fluoride) with Deposited Metal Electrodes.

Abstract

High values of pyroelectric and piezoelectric activity in fully-electroded films of poly(vinylidene fluoride) were obtained by "conventional" (non-corona) poling at room temperature with sufficiently high fields. The avoidance of breakdown while obtaining high activity requires an understanding of the time dependence of both breakdown and activity. Time-to-breakdown as a function of field, and room-temperature pyroelectric activity (7-14 days after poling at 23.5 °C) as a function of poling time and field were obtained for 25-μm biaxially stretched films with evaporated aluminum electrodes. The highest activities were obtained by poling at the highest fields and poling to breakdown. A pyroelectric activity of 36 μCK-1m-2 was measured two weeks after poling with a nominal field of 550 MVm-1 for a nominal poling time of 10 s (reduced by multiple breakdown). The highest activity obtained with no apparent breakdown (31 μCK-1m-2) was measured a week after poling with a field of 400 MVm-1 for 10 s. These values are comparable with the highest that have been reported for this material using any poling temperature or using corona poling.