Ionically crosslinked hydrophilic polymer membranes: Synthesis and measurement of transport properties

Water soluble polymer and copolymer systems containing a poly(carboxylic acid) as one component have been ionically crosslinked in the form of membranes using multivalent metal salts. The permeability coefficients for a homologous series of poly(ethylene glycols) permeating through the ionically crosslinked membranes and a commercial cellophane membrane were determined using a continuous flow dialysis apparatus. Solute concentration changes occurring during dialysis were determined by using an in‐line continuous flow differential refractometer. For the ionically crosslinked membranes the permeability coefficients were found to decrease exponentially with increasing permeant molecular weight. For the cellophane membrane the permeability coefficients were observed to be inversely proportional to the square root of the permeant molecular weight. This square root correlation appears to be consistent with a porous flow model for transport through cellophane membranes.