The study of isothermal decay of surface potential in corona-charged PTFE film

On negatively corona-charged PTFE film, we have measured the isothermal decay of surface potential with different initial voltages at high temperature. At 150°C, a remarkable corssover effect in the decay curves is found. Prom the TSD current spectra, we find the higher the initial voltage, the wider the current peak broadened to low-temperature side. According to a simple mathematical model, the theoretical decay curves are fitted to experimental results. Meanwhile we obtain the trap-modulated mobility μ= 2.2×10⁻¹² cm²/Vsec. In addition, we suggest a "two-trap surface potential field" model and qualitatively explain the crossover effect.