F-19 NMR RELAXATION-TIME T(1) AND SPIN DIFFUSION IN POLYANILINE TRIFLUOROMETHANESULFONATE, [(-C6H4NH-)(CF3SO3)0.5-BULLET-0.5H2O]N

The relaxation time T1 of F-19 NMR and that of H-1 NMR were determined for the polyaniline trifluoromethanesulfonate, [(-C6H4NH-)(CF3SO3)0.5.0.5H2O]n in a temperature range of 4.2-300 K. The H-1 T1 value was practically temperature-independent except for temperatures near 4.2 K, and was governed by a quasi-one-dimensional diffusion of electron spins. The F-19 T1 value of the dopant was explained by a combined effect of the F-F dipolar interaction and the nucleus-electron spin coupling. The latter paramagnetic relaxation term was temperature-dependent in contrast to the H-1 T1, and was explained by an interchain spin diffusion with an activation energy of 1.6 kJ mol-1 and a diffusion velocity of the order of magnitude of 10(11) rad s-1. The interchain diffusion of the spin carriers is expected to occur via close face-to-face contacts of aniline groups.