TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The aprotic solvent is chosen from ethylene carbonate, propylene carbonate, butylene carbonate, gamma -butyrolactone, gamma -valerolactone, N-methylmorpholine-N-oxide, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, ethyl acetate, methyl benzoate, ethyl benzoate, dimethoxymethane, dimethoxyethane, diethoxyethane, tetrahydrofuran, 2-methyl-tetrahydrofuran, 1,3-DL, 4-methyl-1,3-DL, 2-methyl-1,3-DL, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N-ethylpyrrolidone, and sulfolane.    TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The polymer blend has 1.8 meq/g or more sulfonic acid (SO3M) groups remain exchangeable under neutral conditions e.g. in 1 M sodium chloride aqueous solution at pH of 7 after blending polymer (a) and polymer (b). 99% Or more or total of sulfonic acid groups remain exchangeable under neutral conditions after blending polymer (a) and polymer (b). The characteristic ionomer peak of polymer (a) as observed in small angle diffraction measurements is still discernible in the small angle diffraction pattern of the polymer blend. The polymer (b) has pKa value of 2-9, preferably 4-7.5. Preferred Composition: The polymer (b) comprises Bronsted basic groups. The repeating unit (I) comprises recurring elements of formula: -SO2-Ar1(SO3M)p- and recurring elements of formula: -SO2-Ar2-. The sulfonated poly(arylene sulfone) is alternating copolymers between sulfonated and non-sulfonated segments. The alternating copolymers comprise 22 repeating units chosen from formulae (I)-(V). The basic groups of the polymer (b) comprise a nitrogen-containing heterocyclic ring chosen from pyrrolidine, piperidine, azepane, pyrrole, pyridine, azepine, imidazolidine, pyrazolidine, pyrazole, imidazole, benzimidazole, thiazolidine, and thiazole, preferably pyridine, and an electron withdrawing group between the heterocyclic ring and polymer scaffold. The polymer (b) functionalized with basic substituent groups is an aromatic or non-aromatic polymer, preferably polyether, polyester, polyimide, polyamide, polybenzimidazole, polysulfone, polyether sulfone, polyketone, polyether ketone, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polyurethane, polyurea, vinyl-based polymer such as polyolefin and polystyrene, and acryl-based polymer, most preferably polymethyl methacrylate. The basic polymer (b) is any polymer, preferably aromatic polymer such as poly(sulfone) and poly(ketone). The basic polymer (b) comprises a benzyl structural element of formula (VI).Ar1,Ar2=aryl or heteroaryl with 5-18 ring atoms, preferably phenylene;p=1-4;q=10-10000;A,B'=single bond, -O-, -S-, -SO-,-SO2-, -CO-, or alkyl optionally in para-, meta- or ortho-position to each other;andX=group chosen from groups of formulae (i)-(viii).(i) When X comprises -SO2-, r is 1-4 and l is 1 or more; and (ii) When X comprises a -CO-, r is 1-4 and l is more than 1.