mu SR in polymers

muSR can be applied to the study of various dynamical processes in polymers. These processes may relate to carrier motion, as in studies of conducting polymers which make use of muon generated polarons to measure carrier diffusion rates. Alternatively the processes of interest may be related to the structural dynamics of the polymer, which can show dramatic changes around the glass transition temperature. We report here examples of the use of muSR to study the muon states and muon mobility in the polymers polyethylene and polytetrafluoroethylene, where coherent FmuF precession signals have been observed. In the case of polystyrene, muon radical states formed on the phenyl ring have been used to make a detailed study of the dynamical freezing and onset of static disorder that accompanies the glass transition. Finally, we report a study of polaron diffusion in two polyphenylenevinylene conducting polymers. (C) 2002 Elsevier Science B.V. All rights reserved