Surface component of vacuum absorption and resorption currents in polymers. I. Origin and magnitude

Abstract

Absorption and resorption currents have been studied in several polymers, the measurements being made in vacuum and usually at room temperature. It is shown that lateral charge transfer between metallic electrode edges and the immediately adjacent polymer surface accounts for almost all of the measured absorption/resorption current flow in polytetrafluoroethylene (PTFE), and at least half that in polyethylene, polystyrene, and a widely used co-polymer of tetrafluoroethylene and hexafluoropropylene; its contributions in polyvinylchloride (PVC) and polyethyleneterephthalate (PET) are very small. This surface varies approximately as t-1, where t is the time since the external voltage was applied or removed. The exponent varies little from polymer to polymer. The component of the absorption/resorption current flowing in the sample bulk in the co-polymer probably originates in dipole orientation or hopping motion of the charge carriers.