The interfacial charge of silicone rubber (SiR) has been an issue of widespread interest. In the case of industrial production, the introduction of chemical functional groups intensifies the charge accumulation, so it is significant to study the effect of the insertion of different functional groups on the internal trap depth of SiR. In this paper, the energy bands and surface electrostatic potentials of SiR small molecules containing double bonds at both ends and side chains attached to a benzene ring were calculated separately using density function theory. On this basis, the causes of the formation of such traps and their possible sites are determined, and the trap depths formed by both are analyzed. The results indicate that the chemical defects are caused by these small molecular groups, and at the same time, these small molecular groups introduce more localized states, dominated by electronic traps. This suggests that these small molecular groups may be responsible for exacerbating the space charge accumulation. 

Density function theory; Energy bands; Functional groups; Chemical traps; Small molecule groups