Dispersive mobility in polyimide by surface voltage decay measurement

We have submitted samples of Kapton HN polyimide to corona charging and measured its potential decay with an electrostatic voltmeter. In order to analyze and explain the experimental data we propose a two terms mobility. We use a non-dispersive model based on hopping transport and introduce a dispersive term associated with the highly disordered structure of the material. The non-dispersive model alone did not fit well to the data for short times, but our two-terms assumption makes the theoretical expression fit successfully to the experiment. Some important parameters of the material are determined and discussed.