Raman characterization of polyaniline induced conformational changes

Conformational changes induced by temperature and secondary doping process, were followed by Raman resonance spectroscopy and ESR measurements. Raman results give complementary data about the secondary doping process showing that together with the structural change of the polymeric chains, there is also a chemical transformation of quinoid segments into scmiquinoid units. When the temperature is raised, changes in Raman spectra arc coincident with those observed in secondarily doped samples, showing in this way, the importance of polymer conformation in the conductive behaviour. ESR measurements confirm the increasing amount of free radicals when the PANI/CSA films are treated with m-cresol in good agreement with Raman results.