TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The copolymer is a random copolymer or block copolymer. (A) has a weight average molecular weight of 10000-1000000, preferably 30000-800000. The polymer electrolyte membrane further includes: at least one of polymer that is polyimide, polyetherketone, polysulfone, polyethersulfone, polyetherethersulfone, polybenzimidazole, polyphenylene oxide, polyphenylene sulfide, polystyrene, polytrifluorostyrene sulfonic acid, polystyrene sulfonic acid, polyurethane and branched-chained sulfonated polysulfoneketone copolymer; and one or more inorganic materials that are silicon oxide, titanium oxide, inorganic phosphoric acid, sulfonated silicon oxide, sulfonated zirconium oxide or sulfonated zirconium phosphate. Preferred Method: The step of copolymerizing the monomer is carried out so that an equivalent ratio of one or more monomers that are (II) : 2,2'-bis(2-hydroxy-5-biphenylyl)propane: one or more monomers that are (III) is 1:0.05-0.95:0.05-0.95, preferably 1:0.2 to 0.8:0.2 to 0.8. The step of copolymerizing the monomer is carried out under the presence of one or more solvents that are dimethylacetamide, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, methylene chloride, chloroform, tetrahydrofuran, benzene, toluene or xylene. The method comprises: copolymerizing the monomer; oxidizing the copolymer; and introducing the sulfonic acid group to the oxidized copolymer. The step of introducing the sulfonic acid group to the copolymerized polymer is carried out by using one or more sulfonic acid compounds that are concentrated sulfuric acid, chlorosulfonic acid, fuming sulfuric acid and fuming sulfuric triethylphosphate salt. The step of introducing the sulfonic acid group to the copolymerized polymer is carried out at 0-100 degrees C. EXAMPLE - Monomers of 4,4'-difluorodiphenylsulfone (20 mmol), 2,2'-bis(2-hydroxy-5-biphenylyl)propane (8 mmol) and 4,4'-(hexafluoroisopropylidine)diphenol (12 mmol) and potassium carbonate (24 mmol) were added in a flask. Dimethylacetamide (70 ml) and toluene (50 ml) were added to the flask at 140 degrees C for 4 hours. The polymerization reaction was performed for 24 hours by gradually increasing the temperature to 165 degrees C. After the completion of the reaction, the reaction mixture was further worked up to give poly(arylene ether) copolymer.