Photoinjection currents in polymers and electronic charge-exchange at the interface in insulating composites

In the composites of PS(polystyrene) and PMMA( polymethyl-methacrylate), electrons transported from the PMMA layer can pass through the interface more easily than holes from the PMMA layer. Holes from the PS layer can pass through the interface more easily than electrons from the PS layer. As exemplified above, the charge-exchange rate at the interface in insulating composites is affected by the direction of the carrier transport. These asymmetric characteristics are widely seen in insulating composites, such as epoxy-alumina, and seem very important for the better understanding of the insulation performance of the composites. The photoinjection current technique was utilized in order to estimate the conduction levels in PS and PMMA. In this paper, the charge-exchange processes at the polymer-polymer interface are discussed mainly on the basis of the conduction levels in polymers