退火处理对柔性压电材料聚偏氟乙烯基电介质的压电性能影响研究

Effect of annealing treatment on piezoelectric properties of flexible piezoelectric material poly(vinylidene fluoride)-based dielectrics

本文从聚偏氟乙烯基聚合物压电效应的晶体结构基础出发,研究不同退火温度(60~160℃)对薄膜样品表面结晶形貌、结晶尺寸、结晶度,以及关键介电参数包括极化响应曲线和压电系数的影响规律。结果表明:在60~140℃范围内,随着退火温度升高,样品结晶尺寸增大、结晶度提高,从而在极化曲线中表现出更高的剩余极化强度和滞回度,同时压电系数随退火温度升高从11 pC/N增大至27 pC/N。而当退火温度达到160℃时,样品表面出现裂痕缺陷,极化过程较容易发生击穿,且压电系数分散性较大。

On the basis of the crystal structure of piezoelectric effect of polyvinylidene fluoride(PVDF)polymer,the effects of different annealing temperatures(60−160℃)on the surface crystal morphology,crystal size,crystallinity,and key dielectric parameters including polarization response curve and piezoelectric coefficient of PVDF film samples were studied.The results show that the sample crystal size and crystallinity increase with the increase of annealing temperature in the range of 60−140℃.The polarization curves show higher residual polarization intensity and hysteresis,and the piezoelectric coefficient increases from 11 pC/N to 27 pC/N with the increase of annealing temperature.When the annealing temperature reaches 160℃,cracks appear on the surface of sample,and consequently the breakdown is easy to occur in the polarization process,and the dispersity of piezoelectric coefficient is large.