Solid State Ionics, Vol.125, No.1-4, 203-212, 1999
Molecular mobility and protonic conductivity in polymers: hydrogels and ionomers
Dielectric relaxation spectroscopy (DRS) in wide ranges of frequency (10(-2)-10(10) Hz) and temperature (170-350 K) and thermally stimulated depolarization currents (TSDC) techniques (77-300 K) were employed to study protonic conductivity and molecular mobility in poly(ethylene ride) (PEO) hydrogels and in novel segmented polyurethane ionomers. High protonic DC conductivity values are obtained with both systems. In the hydrogels the results are discussed in terms of polymer-water interactions, and of temperature- and water-induced effects. In the ionomers additional information on microphase separation and ionic aggregation obtained by means of DSC, WAXS, SAXS and DMTA measurements provides a basis for discussing structure-property relationships in this class of materials. Proton conductivity in both systems is governed by the motion of the polymeric chains. In the ionomers DC conductivity increases with decreasing hard segment content, suggesting that proton motion occurs through the soft segments phase
Keywords:DIELECTRIC-RELAXATION;WATER INTERACTIONS;LIQUIDS;SYSTEMS;CONDUCTORS;MORPHOLOGY;TRANSITION;MODEL