ELECTRON-TRANSPORT PROPERTIES OF CU-DOPED PVC FILMS

DC conductivity, ac conductivity, dielectric relaxation, and thermally stimulated discharge (TSD) current measurements are made on Cu‐doped PVC films as a function of Cu concentration up to 12%. The dc conductivity of doped films increases by several orders up to a concentration of 4% and thereafter changes little for higher concentrations. The increased conductivity is explained on the basis of an increase in both the number of electrons and the mobility. The exponential temperature dependence of the resistivity of pure PVC films changes to nearly temperature independent behaviour for doped films. These results are explained in terms of a tunnelling conduction mechanism. The ac conductivity of these films favours a hopping conduction model. The increase in ϵ′ and ϵ″ on doping of PVC with Cu is attributed to the presence of Cu+ and Cu2+. Current thermograms of PVC films show a TSD α‐maximum at 338 K followed by a high temperature ρ‐maximum. Doping PVC with metal produces a decrease in the height of the α‐peak and a large increase in the ρ‐peak. The changes in the α‐peak are attributed to the metal‐polymer interaction, while the high temperature currents (ρ‐maximum) are explained in terms of excess charges present in the PVC‐Cu films. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA