Space Charge Analysis of Polyethylene with Chemical Defects Based on Density Function Theory

In recent years, first principle calculation has been widely used in various fields including condensed matter physics, theoretical chemical to get a microscopic and intrinsic understanding of different material and chemical reaction, leading to the formation of a brand new subject, quantum chemistry. In the field of high voltage and insulation, first principle calculation or quantum chemistry have been applied to areas of charge trapping, charge injection and voltage stabilizer. In this paper, in order to clarify charge trapping mechanism of polyethylene, several alkanes with different chemical defects such as carbonyl, alcoholic group have been established with the help of quantum chemistry. The results show that the trapping sites have a strong relationship with the structure of the molecular. The frontier orbitals are both localized around the defects structures and the partial density of states(PDOS) of defect fragments accounts for the vast majority of total density of states(TDOS) at frontier orbital levels. Besides, the electrostatic potential around the defects structures on the van der Waals (VDW) surface are both negative which means these places tend to be holes traps.