TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The repeating unit of the main chain is one or more of 3 repeating units, e.g. group of formula -(CH2-CH(C(O)-CH3))-. The side chain is one or more of 6 compounds, e.g. group of formula 10. The polymer matrix is a polymer resin of formula -(M)m-(X)n- (16).R=En; andM=repeating unit of formula (17);Y1,Y',Z'=tetravalent aromatic organic group or aliphatic organic group;Z=bivalent aromatic organic group or aliphatic organic group;X=repeating unit of formula (18);j,k=1-6;R1=En;m,n=30-5000; andm:n=2:8-8:2.Preferred Material: The repeating unit of the main chain is polystyrene, polyethylene, polyimide, polyamide, polyacrylate, polyamic ester, or polyaniline. The polymer matrix is at least one polymer material consisting of polyimide, polybenzimidazole, polyethersulfone, and/or polyether-ether-ketone. Preferred Parameter: The oligomer solid acid has a molecular weight of 10000-40000. EXAMPLE - About 8.4 g of compound of formula (20), 2.42 g of polyhydroxystyrene, 2.8 g of potassium carbonate and 1.1 g of 18-crown-6 were dissolved in 200 ml of tetrahydrofuran (THF) and refluxed at 60degreesC for 24 hours. The reaction mixture was cooled to room temperature. Then, the acetone was distilled to be removed and was extracted using a toluene/sodium hydroxide solution to separate a toluene layer from the reaction mixture. The separated toluene layer was dried using magnesium sulfate and the toluene was distilled to be concentrated to 50 ml. The result was immersed in ethanol to obtain 8.2 g of compound of formula (22) as a white crystalline solid (yield: 76%). About 5 g of compound (22) (oligomer solid acid precursor) was completely dissolved in 15 ml of sulfuric acid, and then 5 ml of fumed sulfuric acid was added. The mixture was allowed to react at 80degreesC for 12 hours and then precipitated in ether. The precipitate was filtered and then dissolved in water. The resultant was put into a dialysis membrane and refined to obtain the compound of formula (23). About 100 pbw of the polymer matrix (16) with the ratio of m to n being 5:5, and 6.7 pbw of the oligomer solid acid (23) were completely dissolved in N-methyl pyrrolidone and cast at 110degreesC to manufacture a polymer electrolyte membrane.