EPR Studies of Poly(o-Phenetidine)-Poly(Styrenesulfonic Acid) and Poly(2-Ethylaniline)-Poly(Styrenesulfonic Acid) Complexes



This study relates to electron paramagnetic resonance (EPR) of the poly(o-phenetidine)-poly(styrenesulfonic acid) [P(O-P)-PSSA] and poly(2-ethylaniline)-poly(styrenesulfonic acid) [P(2-E)-PSSA] complexes; the polyaniline [PANI], poly(o-phenetidine) [POP], poly(2-ethylaniline) [P2E], and polyaniline-poly(styrenesulfonic acid) [PANI-PSSA] were prepared to be the reference samples; the EPR spectra results were recorded at both 298 K and 77 K, and were analyzed on the basis of the polaron-bipolaron model, which is typical for non-degenerate systems. The EPR spectra results of the substituted polyaniline complexes P(O-P)-PSSA and P(2-E)-PSSA, show temperature-dependent paramagnetism; the narrow line-width arises due to polarons, and the charge transport takes place through both polarons and bipolarons. The narrower line-width of the substituted polyaniline complexes can be attributed to the lower degree of structural disorder, the oxygen absorption of the polymer molecular complexes, and the steric effect by the alkyl group of the polyaniline; the reduced line-widths were consistent with the lower molecular weight of the complexes.