Charge Dynamic Characteristic in Hybrid Film Consisting of Porous PTFE and Teflon FEP with Negatively Corona-Charging

Abstract

The hybrid film of porous polytetrafluoroethylene (PTFE) and Teflon fluorinated ethylene propylene (FEP) is prepared by melting FEP into porous PTFE. This chapter presents an investigation on the charge dynamics of injection, transport, and trapping by means of corona charging and isothermally and thermally stimulated surface-potential decay measurement. The results indicate that the charge dynamics of storage and decay in the hybrid film are very different from single polymer film. When corona charging is performed through side PTFE (C-PTFE), the surface potentials increase at first and then decrease during thermal stimulating discharging. And when charging through side FEP (C-FEP), the surface potential decay only displays a slow change. The reason is interpreted by the assumption that corona charging will generate a large number of microscopic dipoles in the voids of porous PTFE and on interface of hybrid film. The depolarization of microscopic dipoles in the bulk of hybrid film is responsible for the measured change of the surface potentials during aging and storing after charged. The charges released because of thermal exciting run out across the porous PTFE.