The effect of polymer crosslinking on the electrical properties of ethylenevinylacetate poly(3-actylthiophone) polymer blends

A study of the transport properties of a polymer blend consisting of poly(3-octylthiophene) (POT) and ethylenevinylacetate doped with FeCl₃ reveals a change in conductivity mechanism when the material is cross linked by electron irradiation. In heavily irradiated samples and in samples with a high POT content the temperature and the electric field dependences of the dc conductivity are in good agreement with the model of thermal-fluctuation-induced tunneling between metallic particles embedded in a dielectric matrix. In unirradiated samples with a low POT content, however, the data fit best the model of charging-energy-limited tunneling of a granular polymeric metal. These transport properties indicate an increase in the average size of the conducting particles as the polymer blend is cross linked.