温度和湿度对聚四氟乙烯多孔驻极体膜压电活性稳定性的影响

研究了具有开放性孔洞的聚四氟乙烯(voided polytetrafluoroethylene，PTFE)多孔膜和PP蜂窝膜(polypropylene cellular)的驻极体行为和压电活性的温度效应。研究结果指出：和PP蜂窝膜驻极体相比．PTFE多孔膜驻极体呈现出突出的电荷储存和压电活性的温度稳定性；研究了这类稳定性的驻极体和材料的结构根源。PTFE多孔薄膜驻板体这种压电活性的温度稳定性主要依赖于这类驻极体材料电荷储存及材料的本征性能(如力学性质等)的温度稳定性。实验结果还说明：PTFE多孔膜突出的压电系数温度稳定性使它大大扩展了以包括PP在内的空间电荷型多孔膜研制的压电功能元器件的耐温要求。本文还讨论了环境因素(如相对湿度)对这类功能膜压电活性的影响,分析了环境湿度对压电活性影响的结构根源。

Influence of temperature and humidity on stability of piezoelectric activity for porous polytetrafluoroethylene (PTFE) electret film

In this paper, temperature effect of piezoelectricity for open-structure-voided PTFE film and PP(polypropylene) cellular film electrets was studied. Our study results point out that compared with PP cellular film electret, voided PTFE electret has outstanding temperature stability for both charge storage and piezoelectric activity. Furthermore, reasons of electret and structure of the stability for the material were investigated. The temperature stability of the piezoelectricity depends on both the temperature stabilities of charge stored in the piezoelectric film, and of the intrinsic properties of the material such as mechanical properties etc.. The results demonstrate that usable temperature region of the functional devices made by the voided electret films including PP cellular film is markedly expanded due to the outstanding temperature stability of the porous film. Sensitive effect of environmental humidity on piezoelectric activity for the porous PTFE film and microstructure reason of the effect were also investigated.