TECHNOLOGY FOCUS - POLYMERS - Preferred Segment: The chain pattern of polymerization of polymer segment (A) is polyarylene containing aromatic ring-aromatic ring. The segments (A,B) are structural units of formulae (A,B), respectively.Y=bivalent electron attractive group;Z1=bivalent electron donating group or bivalent direct bond;Ar=aromatic group having -SO3H;m,n=0-10;k=1-4;R1-R8=H, fluorine atom, alkyl, fluorine substituted alkyl, allyl, aryl or cyano;W=bivalent electron attractive group or bivalent direct bond;T=single bond or divalent organic group;andp=0 or positive integer.Preferred Copolymer: The copolymer is block copolymer in which polymer segments (A,B) are covalent bonded. The block copolymer is obtained by block copolymerizing compounds of formulae (D',E) and introducing sulfonic acid group to Ar' in structural unit derived from compound of formula (D').X,R',R''=chlorine, bromine, iodine or -OSO2G;G=alkyl, fluorine substituted alkyl or aryl;Y,Z,m,n,k,R1-R8,W,T,p=as defined in above formula;andAr'=aromatic group which does not have -SO3H. EXAMPLE - 2,2-bis(4-hydroxyphenyl-1,1,1,3,3,3-hexafluoro propane (47.1 g), 2,2-bis(4-hydroxyphenyl) fluorene (16.4 g), 4,4'-dichloro benzophenone (53.6 g) and potassium carbonate (71.9 g) were mixed in a flask. Sulfolane (300 ml) and toluene (150 ml) were added in the flask, and reacted at 130degreesC. Water and toluene were removed from the mixture. 4,4'-dichloro benzophenone (6.7 g) was added in the mixture, and reacted at 180degreesC for 8 hours. The reaction mixture was filtered, and product was washed and dried to obtain oligomer having number average molecular weight of 6000. 4-(4-(2,5-dichloro benzoyl) phenoxy)benzenesulfonic acid neopentyl (119 g), oligomer (15.23 g), bis(triphenyl phosphine) nickel dichloride (1.67 g), sodium iodide (0.45 g), triphenyl phosphine (10.49 g) and zinc (15.69 g) were mixed. N,N-dimethylacetamide (390 ml) was added, stirred for 30 minutes and polymerized. The reaction mixture was filtered. The solid product was separated, washed and dried, to obtain polyarylene copolymer having sulfonic acid equivalent of 1.6 meq/g, number average molecular weight of 53200 and weight average molecular weight of 145000. The copolymer (50 g) was dissolved in N-methyl-2-pyrrolidone (262 g). The solution was applied on polyethylene terephthalate film and dried at 80degreesC for 30 minutes and 150degreesC for 60 minutes, to obtain a proton conduction film. The film had thickness of 50 microns, proton conductivity of 0.102 S/cm at 60degreesC, methanol flux of 80 g/hour/m2, methanol separation factor of 0.95 and moisture content of 45 weight%.