| abstract |
The present invention relates to a proton-conductive polymer membrane comprising a polymer compound which has structural repeating units represented by the following formula (1) in which the aromatic units are partially substituted with proton-conductive substituents, wherein the membrane has a solubility in methanol at room temperature of less than 0.01% by weight or solubility in N-methyl-2-pyrrolidone at 5° C. of less than 5% by weight. In the formula, Ar 1 represents a divalent aromatic unit and x represents an integer of 0 to 2. Also, the present invention provides a simple process by which production costs are substantially decreased, for obtaining a proton-conductive polymer membrane having properties applicable in a polymer electrolyte fuel cell. n Ar 1 —SOx (1) |