Corona Charging and Charge Decay on Polyethylene Terephthalate Films (PET).

Surface potential decay (SPD) measurements have been considered as the most appropriate technique to investigate the electrical properties of insulating materials. Its main interest is to avoid any contact with the surface; providing that charge is deposited by means of a DC corona discharge. Besides, the interpretation of the surface potential evolution remains a major problem. For this reason, this study aims at considering surface potential measurements and the mechanisms of the potential decay and transport processes that might be involved in the decay. To reach a conclusion, samples that were used took the form of polyethylene terephthalate films (thickness: 0.5 mm; surface: 50 mm x50 mm). A negative corona discharge produced in a needle-grid-plate electrode system was employed to charge the surface of the film samples. All surface potential decay measurements were carried out in a commercial climatic chamber, where relative humidity RH and temperature T were rigorously controlled. Initially, we have shown an injection process of the charge deposited on the surface of the material. The investigation on the kinetics of charge carriers (charge carrier mobility), allowed us to determine the mobility of the charge derived in the material. We noted a strong dependence of the charge density put on the evolution of SPD. [ABSTRACT FROM AUTHOR]