Morphology and ion transport in glassy polymerized ionic liquids

The impact of macromolecular structure on ion dynamics and morphology in ammonium and imidazolium based glassy polymerized ionic liquids are investigated using broadband dielectric spectroscopy and wide angle X-ray scattering (WAXS). A new approach is suggested to determine ionic mobility in a broad range spanning up to five orders of magnitude below the calorimetric glass transition temperaturesof polymerized ionic liquids is proposed, providing access to a regime of diffusivities that is inaccessible to many current experimental techniques. A quantitative agreement between the mean ion jump lengths from dielectric data and the ion-to-ion correlation lengths from WAXS is found. The ion mobility is found to be more sensitive to variation of the molecular structure compared to the effective number density of the mobile ions. These results showcase the subtle interplay between the molecular structure, morphology and ion dynamics in polymerized ionic liquids.