Thermally stimulated discharge current study of surface charge release in polyethylene by corona-generated excited molecules, and the crossover phenomenon

Thermally stimulated discharge (TSD) current studies on negatively-corona-charged low-density polyethylene reveal a deep surface trap distribution centered at 95 °C and a shallow surface and bulk distribution centered at 55 °C. TSD also shows that corona-generated neutral excited gas molecules in the surrounding air free the shallow surface trapped charge which moves into the bulk under its own field, and can be retrapped or transit through the sample. Crossover in surface potential decay curves is caused by these molecules, and can be eliminated by removing them from the corona discharge.