Oxygen-induced ESR line broadening in conducting polymers : the effect of moisture

The oxygen-induced ESR line broadening has been investigated in the case of the conducting polymer polyaniline. Pumping under vacuum results in a narrowing of the ESR linewidth. After initial pumping various oxygen containing gas has been applied to the sample (pure O2, ambient air, and dry air) and the linewidth has been measured as a function of time. The residual water in these gases was found to drastically affect the line broadening behavior. In particular, in absence of moisture the slow “relaxation” of the linewidth, which was reported before, is suppressed.