Oxygen-induced ESR line broadening in conducting polymers

The oxygen-induced ESR line broadening has been investigated in the case of the conducting polymer polyaniline in powder and film form. Pumping under vacuum results in a narrowing of the ESR linewith. After initial pumping various oxygen containing gas has been applied to the sample (pure O2, O2 + N2, O2 + He), and the linewidth has been measured as a function of time. At first, the linewidth increases similarly in the various cases. Then, different behaviors are observed, which are discussed according to the relative velocity of the sorption / diffusion process of oxygen and its partner. The connection of the line broadening with the samlpe conductivity is also discussed.