Charge relaxation in structures containing non-polar polymer-metal interfaces

Abstract

The excess charge relaxation in electret structures based on Teflon-FEP films, particularly the charge behaviour in the region of polymer-metal contact, has been investigated. Measurements were made using both the standard electret techniques and a special experimental method, based on observation of the partial recovery of voltage of sandwich electret structures during reheating after forced corona-discharge. It has been found that a specific macro-non-uniformity region exists near the FEP-Al interface, where deep trapping of charges drifting through the FEP film occurs. Using experimental measurements and an appropriate analysis, the authors determine the energy distribution of the traps located near the FEP-Al interface estimate the dimensions of this region to be about 0.3.-0.75 mu m from the Al electrode.