NOVELTY - Poly(arylene ether) copolymer (A) is claimed.    USE - (A) is useful in polymer electrolyte membrane, which is useful in a membrane-electrode assembly, where the electrolyte membrane is a polymer electrolyte membrane for fuel cell (all claimed), and the membrane-electrode assembly is fuel electrode (anode), an oxygen electrode (cathode) and an electrolyte membrane. The membrane-electrode assembly is useful in battery field, which is fuel battery or rechargeable battery. (A) is useful in vehicles including motor vehicles, which is automobiles (which includes passenger vehicles, buses and commercial vehicles).    ADVANTAGE - (A) provides excellent performance properties. The polymer membranes provide dimensional stability to moisture through forming effective ion channels and relatively widening the hydrophobic portion. (A) provides high hydrogen ion conductivity.    DETAILED DESCRIPTION - Poly(arylene ether) copolymer (A) having a structure of formula (I) is claimed.    R = H or sulfonic acid (-SO3-M+), preferably SO3H;    M+ = positive ion;    Ar1 = 1-methyl-4-(p-tolylsulfonyl)benzene, di-p-tolyl-methanone, 2,3,5,6,2',3',5',6'-octafluoro-4,4'-dimethyl-biphenyl, 1,2,4,5-tetrafluoro-3,6-dimethyl-benzene, 2,6-dimethyl-benzonitrile or (4-(4-methyl-benzoyl)-phenyl)-p-tolyl-methanone;    Ar2 = bis-1-methyl-4-(2,2,2-trifluoro-1-trifluoromethyl-ethyl)-benzene, bis-5-isopropyl-1,2,3-trimethyl-benzene, bis-4-methyl-benzenethiol, 3,5,3',5'-tetramethyl-biphenyl-4,4'-diol, 4-mercapto-phenol or 1-methyl-4-(p-tolylsulfonyl)benzene;    X = 0.01-1, preferably 0.2-0.8; and    n = 10-800.    INDEPENDENT CLAIMS are included for:    (1) a method for manufacturing (A) comprising copolymerizing 2,2'-bis(2-hydroxy-5-biphenylyl)propane, one or more monomers (II) having a structure of formula ((a)-(f)), and one or more monomers (III) of formulae ((g) and (h)), 4-(2,2,2-trifluoro-1-trifluoromethyl-ethyl)-phenol, 4-isopropyl-2,6-dimethyl-phenol, 3,5,3',5'-tetramethyl-biphenyl-4,4'-diol, bis-4-mercapto-phenol or 1-methyl-4-(p-tolylsulfonyl)benzene, and introducing a sulfonic acid group to the copolymerized polymer; and    (2) a polymer electrolyte membrane comprising (I) that has the sulfonic acid group.    X = halo.