氟聚合物压电驻极体的压电性及其电荷的动态行为

描述了一种可控微结构的多孔聚合物压电功能膜的制备方法，讨论了采用该工艺制备的聚四氟乙烯(PTFE)和全氟乙丙烯共聚物(FEP)复合膜压电驻极体的压电性能及其热稳定性.通过等温压电系数衰减和短路热刺激放电(TSD)方法，研究了氟聚合物复合膜压电活性热稳定性改善的根源，以及脱阱电荷输运和复合的特性.结果表明，这类氟聚合物压电驻极体膜的准静态压电系数d₃₃可高达2200pC/N；压电系数d₃₃的压强特性在直到20kPa的压强范围内呈现良好的 关键词： 氟聚合物 压电驻极体 热稳定性 电荷动态特性

Piezoelectric properties and charge transport for fluorocarbon polymers with cellular structure

A new method for prepering piezoelectric polymer with cellular structure (piezoelectret) is introduced. Their piezoelectric activity and thermal stability are investigated for the fluorocarbon piezoelectret films produced in this method. The quasistatic piezoelectric d₃₃ coefficients up to 2200pC/N are obtained for the fluorocarbon piezoelectret films; d₃₃ coefficients are relatively independent on the applied pressure in the range of 20kPa; comparing to polypropylene piezoelectret film the new fluorocarbon films show not only higher values of d₃₃，but also much better thermal stability; Furthermore，the thermal stability of the fluorocarbon piezoelectret film can be further improved by the process of pre-ageing. The enhanced thermal stability of d₃₃ for such fluorocarbon films is due to the good thermal stability of charges in fluoroethylenepropylene (FEP) and polytetrafluoroethylene (PTFE)，and the dimension stability of such cellular structure. The charge recombination is mainly through the drifting of the detraped charges along the inside surfaces of the cavities when the films are thermally stimulated.