Suppression of charge injection to linear low density polyethylene by surface fluorination modification

To suppress charge injection at electrodes, direct fluorination using fluorine gas was used in linear low density polyethylene. High fluorination degree was obtained as indicated by attenuated total reflection infrared spectroscopy. Remarkable suppression of charge injection due to the surface fluorination was found by the space charge distribution measurements using the laser-induced pressure pulse method. The possible suppression mechanisms of charge injection were discussed, one of which, the effect of fluorination on the charge traps in surface layer was deeply investigated by the thermally stimulated discharge technique. The results indicate that fluorination caused the charge traps in surface layer remarkably deepened and the charge captured in the deep traps blocked or shielded the further charge injection.