Charge Transport in Polyimide Electret During and After Corona Charging

The influence of bulk conductivity at elevated temperature on injected charge depth along the thickness of polyimide foil was investigated by means of heat pulse technique and a three terminal-electrode system. The transport rule of detrapped real charge after corona charging and the main reason causing the decay of the charge in the bulk of the sample during thermally stimulated discharge were studied by measuring mean charge depths, steady-state conduction current-temperature curve and effective surface charge density.