Method for varying the transport properties of a film cast from a sulfonated copolymer

摘要

A method for varying the transport properties of a film cast from a polymer having at least two polymer end blocks A and at least one polymer interior block B wherein each A block is a polymer block resistant to sulfonation and each B block is a polymer block susceptible to sulfonation, and wherein said A and B blocks do not contain any significant levels of olefinic unsaturation. The method includes casting the polymer using a solvent mixture having two or more solvents selected from the group consisting of polar solvents and non-polar solvents.