恒流电晕充电对聚四氟乙烯多孔薄膜驻极体驻极态的影响

Influence of constant-current corona charging on electret state of porous PTFE film electret

利用常温下恒流和恒压电晕充电、充电后的等温表面电位衰减、热刺激放电和扫描电镜等实验手段研究了恒流和恒压电晕充电技术对聚四氟乙烯多孔薄膜驻极体驻极态的影响 .与恒压电晕充电相比较 ,恒流电晕充电时由于流过薄膜的电流恒定 ,增加了注入电荷在多孔结构厚度方向界面处的俘获概率 ,使沉积电荷密度上升 ,改善了驻极体的储电能力 .然而 ,这些位于不同层深多孔界面处的俘获电荷在这类功能膜储存或使用过程中 ,经外激发从脱阱位置以跳动 (hopping)

The influence of constant current and constant voltage corona charging technique on the electret state of porous polytetrafluoroethylene(PTFE) film electret has been studied by constant current and constant voltage corona charging at room temperature, isothermal surface potential decay, thermally stimulated discharge(TSD) and SEM(scanning electron microscope), etc. Compared to the constant voltage corona charging, the current through films is constant during constant current charging, therefore, the trapping possibility along the thickness direction of porous structure increases and the charge density goes up, which improves the charge storage ability of the electret. However, the charges trapped in the dielectric surfaces of the interfaces with different depths along the thickness of the sample are externally stimulated during storage or application, their transport paths to the back electrode from the trapping positions are relatively shorter according to the hopping model of the charges, therefore the charge decay is accelerated and the charge stability is decreased.