Casting solvent effects on the permeability of polymer films of differing quaternary ammonium (cation) content.

Films of certain acrylate-methacrylate copolymers of varying cation (quaternary ammonium) content were cast from three different solvents: acetone, chloroform, and ethanol; their permeability to urea was determined at 30 degrees C. In films containing 66 mole cation mol-1 polymer chain, and cast from acetone, chloroform or ethanol, the permeation rates were 480,900 and 2807 mg h-1, respectively. Differences in permeation rates were however less significant when polymers of cation content lower than 46 mole cation mol-1 polymer chain were used to form films. This observation may relate to differences in the degree of dissociation of the polymer in the different solvents.