Measurement and analysis of electric potential decay in corona charged low-density polyethylene films

In this paper, corona charged LDPE film was tested using a standard static potential monitor and the pulsed electro-acoustic (PEA) technique to observe the surface potential decay. A wide range of voltages and different corona charging times, different sample thicknesses and multi-layer films were used to demonstrate influential factors for surface potential decay. These provide a direct experimental evidence to support the bulk transport process. An important finding from the PEA results is that bipolar charge injection takes place during corona charging process and in subsequently decay process. The new evidence challenges the existing surface potential decay models which were developed based on a single charge carrier injection.