氟聚合物压电驻极体的压电性及其电荷的动态行为  

Piezoelectric properties and charge transport for fluorocarbon polymers with cellular structure

作　　者：张晓青[1] 黄金峰[1] 王飞鹏[1] 夏钟福[1] 

机构地区：[1]同济大学波耳固体物理研究所,上海200092

出　　处：《物理学报》2008年第3期1902-1907,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50503018);上海市青年科技启明星计划(批准号:07QA14056);上海市自然科学基金(批准号:05ZR14125)资助的课题~~

摘　　要：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线性;与聚丙烯(PP)压电驻极体膜相比较,氟聚合物复合膜压电驻极体不但具有更高的压电活性,而且呈现更优良的热稳定性,并且预老化处理可以进一步提高其压电活性的热稳定性.氟聚合物热稳定性的提高是源于材料微结构的稳定以及基体电介质的优异电荷储存性能;储存在微孔洞上下固体介质壁上的空间电荷在热激发脱阱后,在驻极体电场作用下的输运路径主要沿着固体介质层的表面迁移并与异性电荷复合.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 2200 pC/N are obtained for the fluorocarbon piezoelectret films; d33 coefficients are relatively independent on the applied pressure in the range of 20 kPa; 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.

关 键 词：氟聚合物 压电驻极体 热稳定性 电荷动态特性 

分 类 号：O484[理学—固体物理] TB43[理学—物理]