Anomalous recovery of the remanent polarization after heatingpolarized PVDF films up to 180° C

摘要

Biaxially stretched 38-μm-thick PVDF (polyvinylidene fluoride)samples with about 80% β content were poled at room temperature atE=200 MV/m for 5 s. The remanent polarization was measured with the PPSmethod first at 20° C, then after heating to 180° C, and a thirdtime after cooling the sample to room temperature again, to determineits temperature-dependent stability. To distinguish between irreversibleand reversible polarization loss due to heating of polarized PVDF films,the polarization was measured at elevated temperatures and after coolingdown to room temperature again. The reversible polarization loss causesthe pyroelectricity of PVDF