MULTIFREQUENCY EPR OF POLYANILINE DERIVATIVE POLYMERS

这个项目的目的是阐明维度

The objective of this project is to elucidate the dimensionality of the charge transport and paramagnetism in five newly synthesized polyaniline-based polymers, utilizing the frequency dependence of the linewidths of EPR signals. We have already made detailed measurements at 9.5 and 95 GHz on pure polyaniline, poly(o-toluidine), poly(o-ethylaniline), and poly(o-propylaniline). The 95 GHz data afforded the most accurate g-values to date on this family of polymers. The RPR linewidths exhibit a highly unusual behavior for the latter two polymers: a significant (~20%) increase in the linewidth upon evacuation. Normally, evacuation decreases EPR linewidths because the removal of oxygen which is involved in dipolar (i.e., exchange) coupling. The linewidths also exhibit frequency dependence, pointing to low dimensional effects. Additional measurements are under progress on three more derivatives with a view of delineating the effects of chemical substituents on the low-dimensional behavior. Variable temperature studies are also planned in order to obtain additional information on any low-frequency dynamics in these materials.