Surface charge decay on insulating films

The nature of charge decay and the mechanisms of surface conduction in LDPE (low-density polyethylene) and other polymeric insulating films was investigated in different environments and after pretreatment of the surfaces. Results are reported on the surface charge decay of LDPE films (untreated and gamma-irradiated) after both corona charging and contact charging. The behavior of surface charge decay after corona charging of LDPE shows that there is little evidence of lateral migration of charge on the surface plane. The deposited charges are held strongly on the surface and tend to decay very slowly. It is suggested that the mechanisms of decay of charges provided by momentary contact charging may not be dissimilar to those of corona charging. The ions and charges deposited in the two respective cases may provide a dielectric polarization which is then followed by the slow diffusion of charges in the bulk