Charging of polymer foils using liquid contacts

A very simple technique is reported for charging 25.4- and 50.8-μm foils of polyfluoroethylenepropylene (FEP) using conducting liquid contacts. At 23°C in laboratory atmosphere, decay time constants exceed 20 years for foils initially charged to 500 V with ethyl alcohol contacts. Measurements of accelerated decay at 100°C are interpreted in terms of rapid injection and trapping of surface charge followed by drift of thermally generated carriers under the internal field of the trapped surface charge.