TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The block copolymer is a multi-block copolymer.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Agents: The sulfonating agent is sodium salt of bromoethane sulfonic acid or alkyl sultone, preferably 1,3-propanesultone or 1,4-butanesultone. The ion exchange capacity of the electrolyte film is 0.1-5 meq/g. Preferred Definitions:    m, n, p, q = 0;    c+d, g+h = 0; and    R1 = ethylene, propylene or butylene.    EXAMPLE - Methoxy hydroquinone (3.03 g), 4,4'-difluorodiphenyl sulfone (6.1 g) and potassium carbonate (4.03 g) were mixed in a flask. N-methylpyrrolidone (45 ml) and toluene (23 ml) were added and stirred to form N-methyl pyrrolidone reaction solution of block unit precursor (A). Hydroquinone (2.64 g), 4,4'-difluorodiphenylsulfone (5.49 g) and potassium carbonate (4.48 g) were mixed in a flask. N-methyl pyrrolidone (45 ml) and toluene (23 ml) were added and stirred to form N-methylpyrrolidone reaction solution of block unit precursor (B). Precursors (A) and (B) were mixed at 150 degrees C for 10 hours to form reaction liquid mixture, then cooled to room temperature and polymer precipitated. The precipitated polymer was filtered, washed and dried to form polyarylene ether sulfone group block copolymer (15.4 g) having methoxy group.    The obtained block copolymer (15 g) was dissolved in methylene chloride and cooled to 4 degrees C. Boron tribromide and methylene chloride solution were added and the reaction solution poured into ethanol (900 ml) and polymer precipitated. The precipitated polymer was washed and polyarylene ether sulfone group block copolymer (13.2 g) having hydroxyl group was obtained. The obtained copolymer was dissolved in dimethyl sulfoxide (100 ml) and methanol solution of sodium ethoxide added and stirred at room temperature for 1 hour. 1,4-Butanesultone was added and stirred at room temperature for 12 hours to form polyarylene ether group copolymer (2.03 g) having sulfobutoxy group with yield of 86%. The obtained block copolymer was dissolved in dimethyl sulfoxide to form a solution, which was poured on glass and dried to form polymer film of thickness 80 microm and ion exchange capacity of 1.1 meq/g. The film had proton conductivity of 4x10-2 S/cm at 80 degrees C and 90% relative humidity.