Probing proton mobility in polyvinazene and its sulfonated derivatives using H-1 solid-state NMR

The proton dynamics of PV and its sulfonated derivatives have been studied using high-resolution solid state H-1 MAS NMR. Variable temperature experiments were used to determine the activation energy for transportation of hydrogen bonded protons, found to be 22 +/- 1 kJ center dot mol(-1) for PV and 13 +/- 1 kJ - mol(-1) for PV-B25. The proton exchange between sulfonic acid group and vinazene ring observed from both variable temperature experiments and H-1 EXSY NMR experiments provides a good explanation for this difference. A rotorsynchronized homonuclear double quantum filter sequence was used to distinguish protons of differing mobilities. A model is proposed to understand the distinct proton mobilities in these materials.