Model approach for describing the properties of ion-exchange membranes

A system of transport and structural parameters is proposed that is based on a model of a swollen ion-exchange membrane as a polyphase system and on the use of the generalized conductivity principle. These parameters characterize the transport of ions and water through a structurally heterogeneous membrane, the volume fractions of the conducting phases, and their orientation with respect to the electric current flow. The basic experimental data for determining the parameters are the concentration dependences of the specific conductivity and the diffusion and electroosmotic permeabilities under standardized experimental conditions. Information on the transport and structural parameters of commercial and prototype samples of ion-exchange membranes with polymer matrices of various nature is provided and discussed.