Spin diffusion in semidilute random coil polymers studied by pulsed gradient spin-echo NMR

Pulsed gradient spin-echo NMR investigations of polymer mean-squared segmental displacements in semidilute solutions of high molar mass polystyrene in deuteriotoluene have revealed evidence for spin diffusion, an effect which is apparent in the difference between spin-echo and stimulated-echo experiments. The time dependence of magnetization quasi-particle displacements is found and is consistent with for intrachain diffusion, in contrast to the dominance of interchain effects in melts.