Space charge analysis of plasma pre-processed PTFE thin films

Space and surface charge behavior of corona-charged PTFE thin films were studied experimentally by space charge density distribution measurement and thermally stimulated discharge current (TSDC) measurement. The effect of the antistatic process using low pressure discharge plasma and a charge elimination process dipping in city water was examined. Surface composition of the samples which were plasma processed was analysed with X-ray photoelectron spectroscopy (XPS) to study the mechanisms of antistatic process. It was found that charge elimination performance was enhanced when samples were plasma-processed independently of the kind of ambient gas during the processing. Oxygen and nitrogen atoms were observed from the XPS measurement of plasma processed samples. In particular a large amount of nitrogen atoms were found on the surface of the samples plasma-processed in nitrogen gas. The samples processed in nitrogen gas showed a large hetero TSDC peak at room temperature before charge elimination process. This may be due to amino groups on the sample surface that were generated during plasma processing.