TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The copolymer has a weight average molecular weight of greater than or equal to 30000. The copolymer can comprise polysulfone and sulfonimide repeating units of formula (IV).Ar'=divalent group of formula (V), (VI) or (VII) optionally substituted with one or more F;Rf'=straight chain, branched or cyclic 1-20C perfluorinated alkylene optionally substituted with ether oxygen or halo;M'=M;m=1-6; andn, p=integers indicating the number of repeat units in the copolymer.Q=S, SO2, CO, or CR1R2; andR1, R2=branched or cyclic 1-10C perfluorinated alkyl or can together form a ring. Preferred Definitions:    M=H, Li, Na, or K; and    T=Ph.    EXAMPLE - Inside a glove box, a 100 mL round-bottom flask was charged with bis(1,5-cyclooctadiene)nickel(0) (4.45 g), cyclooctadiene (1.75 g), 2,2'-bipyridine (2.52 g), and dimethylacetamide (DMAc, 20 mL). The flask was heated to 70 degrees C under nitrogen for 30 minutes to give a dark violet-colored solution. Inside the glove box, a 50 mL round-bottom flask charged with 4,4'-dibromo-biphenyl-2,2'-disulfonic acid sodium salt (2.064 g), 2,2'-bis-benzenesulfonyl-4,4'-dibromo-biphenyl (2.369 g), and DMAc (30 mL). This flask was heated to 70 degrees C to dissolve the monomers and the solution was added dropwise by cannula to the reaction flask under nitrogen. The monomers were washed with additional DMAc (5 mL). The polymerization quickly began to develop gel, so it was diluted with additional DMAc (10 mL) and the temperature was increased to 100 degrees C overnight. The reaction mixture was poured into concentrated hydrochloric acid to precipitate the polymer and the mixture was chopped in a blender to disperse the polymer into particles. The polymer was collected by vacuum filtration, washed with concentrated hydrochloric acid followed by water then methanol, and dried in vacuum oven at 70 degrees C under nitrogen purge to give 1.54 g (52% yield) of 1:1 copolymer, poly((4,4'-biphenylene-2,2'-disulfonic acid)-co-(2,2'-bis-benzenesulfonyl-4,4'-biphenylene)). The weight average molecular weight of the copolymer was 39100. The copolymer (0.99 g) was then dissolved in DMAc (12.4 mL) using heat and filtered into a polymethylpentene Petri dish. The dish was placed on a leveled drying stage in a nitrogen-purged drying chamber. The dried membrane lifted free of the dish on its own, then was dried further at 80 degrees C in a nitrogen-purged vacuum oven. The membrane was treated with 15% nitric acid overnight, then washed with deionized water three times until neutral. The membrane had thickness of 124 mu m and in-plane conductivity of 63.2 mS/cm at 80 degrees C and at 95% relative humidity.