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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 preparation method of a porous polymer piezoelectric functional film with controlled microstructure is described. The effects of the composite piezoelectric film of polytetrafluoroethylene (PTFE) and perfluoropropylene copolymer (FEP) prepared by this process are discussed. The piezoelectric properties and thermal stability of bulk polymer films were investigated by means of isothermal piezoelectric coefficient reduction and short-circuit thermal stimulation discharge (TSD) methods. The results showed that the improvement of the piezoelectric active thermal stability of the fluoropolymer composite films, The results show that the quasi-static piezoelectric coefficient d33 of these fluoropolymer piezoelectric electret film can reach as high as 2200pC / N and the pressure characteristic of piezoelectric coefficient d33 shows good linearity in the pressure range up to 20kPa ; Compared with the polypropylene (PP) piezoelectric electret film, the fluoropolymer composite film piezoelectric electret not only has higher piezoelectric activity, but also exhibits more excellent thermal stability, and the pre-aging treatment can further To improve the thermal stability of the piezoelectric activity.Fluoropolymer thermal stability is derived from the stability of the material microstructure and the excellent charge storage properties of the matrix dielectric; stored in the micro-cavity wall space above and below the solid charge in the heat Excited off the trap, The transport path of the electric field to migrate along the main surface of the solid electret dielectric layer and charge recombination with the opposite sex.