Title :
Interesting influences of fluorinated surface layers on space charge behavior in polyethylene
Author :
Chenxia Liu ; Zhenlian An ; Xuan Chen ; Feihu Zheng ; Yewen Zhang
Author_Institution :
Dept. of Phys., Tongji Univ., Shanghai, China
Abstract :
Polyethylene (PE) samples were surface fluorinated for different times in a laboratory vessel. Space charge measurements reveal interesting changes in space charge behavior with fluorination time. ATR-IR analyses suggest an increasing degree of fluorination and fluorinated layer thickness with fluorination time, and SEM images of cross-section of the fluorinated samples give direct information on the fluorinated layer thicknesses. Surface energy calculations indirectly indicate a dramatic increase in permittivity or polarity of the fluorinated layers with different degrees. Open-circuit TSD current measurements show that the fluorinated layers have different charge trapping properties and increasing barrier properties to diffusion of the chemical species from the semi-conductive electrode to the PE with fluorination time. This therefore suggests a decrease in free volume in the surface layer with fluorination time and a corresponding decrease in charge transport. The charge transport properties and thickness of the fluorinated layer are more important to suppress space charge accumulation in the bulk, although high permittivity and deeply trapped charge in the surface layer would reduce the interface electric field and decrease charge injection.
Keywords :
attenuated total reflection; charge injection; charge measurement; electric current measurement; electric fields; fluorine; polyethylene insulation; scanning electron microscopy; space charge; surface energy; ATR-IR analyses; PE samples; SEM images; barrier properties; charge injection; charge transport properties; charge trapping properties; chemical species; fluorinated layer thickness; fluorinated surface layers; fluorination time; interface electric field; laboratory vessel; open-circuit TSD current measurements; polyethylene; semiconductive electrode; space charge accumulation; space charge behavior; space charge measurements; surface energy calculations; Chemicals; Electrodes; Materials; Permittivity; Space charge; Surface treatment; Polyethylene; Space charge; Surface fluorination; Surface layer characteristics;
Conference_Titel :
Electrical Insulating Materials (ISEIM), Proceedings of 2011 International Conference on
Conference_Location :
Kyoto
Print_ISBN :
978-4-88686-074-3
DOI :
10.1109/ISEIM.2011.6826301