The oxygen-induced ESR line broadening has been investigated in the case of the conducting polymer polyaniline in powder and in film form. Pumping under vacuum results in a narrowing of the ESR linewidth. After initial pumping various oxygen containing gases have been applied to the sample (pure ${\mathrm{O}}_2$, ambient air, dry air) and the linewidth has been measured as a function of time. The residual water in these gases was found to seriously affect the narrowing behavior of the linewidth. A theoretical calculation is proposed showing that the line broadening is proportional to the oxygen concentration and to the polaron mobility. Considering the linewidth dependence upon applied oxygen pressure an evaluation of the polaron mobility is obtained. This value is consistent with the values estimated from previous spin dynamics studies. An evaluation of the exchange integral is also given.

• Received 25 September 1995

DOI:https://doi.org/10.1103/PhysRevB.53.14309