Water self-diffusion and ionic conductivity in perfluorinated sulfocationic membranes MF-4SK

Water self-diffusion and ion mobilities in various ionic forms (H + , Li + , Na + , Rb + , Cs + , and Ba 2+ ) of perfluorinated sulfocationic membranes MF-4SK were studied by NMR and impedance spectroscopy. When degrees of hydration are low, the self-diffusion coefficients of water and ionic conductivities are considerably affected by the water content of the membrane. The self-diffusion coefficients decrease in the order H + > Ba 2+ > Cs + > Rb + > Na + > Li + , whereas the ion mobility decreases in the order H + > Li + > Na + > Cs + > Ba 2+ .