TECHNOLOGY FOCUS - POLYMERS - Preferred Components: In the polymer the repeating units of formula (I) correspond to (5E), where (1A) etc correspond to the structures listed under (1A) to (1T):-O-R6- (1A)-S-R6- (1B)-O-R6-SO2-R6- (1C)-O-R6-SO2-R6-O-R6- (1D)-O-R6-SO2-R6-O-R6-R6- (1E)-O-R6-SO2-R6-O-R6-C(CH3)2-R6- (1F)-O-R6-SO2-R6-R6-SO2-R6- (1G)-O-R6-SO2-R6-R6-SO2-R6-O-R6-SO2-R6- (1H)-(-O-R6-SO2-R6-)x-(-SO2-R6-R6-)y- (1I)0 less than x, y less than 100%-O-R6-CO-R6- (1J)-O-R6-CO-R6-CO-R6- (1K)-O-R6-CO-R6-O-R6-CO-R6-CO-R6- (1L)-O-R6-O-R6-CO-R6- (1M)-O-R6-O-R6-CO-R6-CO-R6- (1N)-R6- (1P)-R6-CH=CH- (1Q)-CHR7-CH2- (1R)R6 = phenylene, 1,3-phenylene, 1,4-phenylene, 4,4'-biphenyl, a divalent residue of a heteroaromatic, a divalent residue of a 10C-aromatic, a divalent residue of a 14C aromatic and/or a divalent residue of a pyrene residue;R77, R8, and R9 = a 4- or 3-bond aromatic or heteroaromatic group, andR = the inner half of a repeating unit , O, S, or amino, which has a group containing H, a 1-20C hydrocarbon, preferably optionally branched alkyl, alkoxy, or aryl.At 25degreesC the polymer has a specific current flow resistance of 100 ohm. At 90degreesC in deionized water the polymer shows swelling less than 100%. The polymer has an ion exchange capacity of 0.5-1.9 meq/g. The polymer mixture contains: (1) at least one polymer, educt with a functional group (a), (2) at least one with a functional group (b), and (3) with a functional group d.Preferred Process: (1) at least polymer educt has functional groups (a) and (b), (2) at least one polymer educt has functional groups (d). A polymer or e duct polymer is dissolved in a polar aprotic solvent, preferably N,N-dimethyl formamide, N,N-dimethyl acetamide, N-methylpyrrolidone, dimethylsulfoxide, or sulfolane and is reacted with a halogen compound. In the process, (a) the polymer solution is spread onto a base as a film, and (b) a polymer membrane is obtained by evaporation of the solvent at a temperature above 25degreesC and/or under pressure less than 1000 mbar. A process in which the polymer (a) is treated with an acid in a first step, preferably doped with phosphoric acid, (b) is treated with deionized water in a second step, and before the first step is optionally treated with a lye.