Porous matrices and membrane matrices comprising sulfonated aryl sulfonate polymers are prepared from a sulfonated aryl sulfonate polymer solution which is made by dissolving an aryl sulfonate polymer, and optionally a polymer other than aryl sulfonate, in a sulfonating acid solvent such as sulfuric acid. The solutions are then cast as wet films from which the matrices are coagulated. By controlling composition and process parameters, hydrophilic matrices of varying morphology are produced.