1H and 19F NMR Relaxations of Electroconducting Polypyrrole and Polythiophene Trifluoromethanesulfonates

Abstract

Abstract The NMR relaxation time T1 of 1H and that of 19F were determined for polypyrrole and polythiophene doped with trifluoromethanesulfonate (triflate) or perchlorate ions. The 1H T1 is governed by the paramagnetism of the polymer chains. The 19F T1 of the triflate ions is explained by the combined effect of the F–F dipolar interaction and the electron–nucleus coupling. The activation energy for CF3 reorientation about the C3 axis was 7.5 kJ mol−1 for polypyrrole triflate and 15 kJ mol−1 for the corresponding polythiophene.