Thermally stimulated currents due to ionic carriers in polysulfone

Polarized polysulfone (PSF) films showed two TSC (thermally stimulated current) peaks in the high-temperature region: P₁ at 175°C and P₂ at 195°C. The P₁ peak linearly increased with poling field and then saturated. The P₂ peak strongly depended on the nature of the electrode, especially the cathode. The thermally stimulated surface potential increased in the region of the P₁ peak and disappeared in the region of the P ₂ peak. Moreover, the thermal pulse current experiments revealed the existence of positive hetero-space-charge near the cathode. From these results, the P₁ peak was ascribed to the release of positive hetero-space-charge. The P₂ peak is shown to be associated with the neutralization of positive ions at the cathode