Numerical modeling of surface potential decay of corona charged polymeric material

Monitoring surface potential decay of a corona charged polymeric material is a powerful tool to characterize electrical properties such as charge transport, trapping/detrapping and recombination. Over the years, various models have been proposed to describe charge transport within the material and one common feature in these models is that they were all based on single charge injection from the charged surface. Recent experimental evidence on the corona charged polyethylene film shows clearly that bipolar charge injection takes place in corona charged sample especially at high surface potentials. A new model based on a bipolar charge injection has been proposed. In the present paper numerical simulations have been carried out using the model and results have been compared with surface potential decays obtained from 50 μm low density polyethylene films after corona charged. The simulation results show that several features experimentally observed can be readily revealed using the bipolar charge injection model. More importantly, the modeling can illustrate charge dynamics across the sample and allows one to extract parameters that are associated with material properties.