TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The fluorinated monomer(s) containing ethylene unsaturation comprises vinylidene fluoride; 2-8C perfluoro-olefins, preferably tetrafluoroethylene (TFE); 2-8C chloro, bromo, and/or iodo fluoro-olefins, such as chlorotrifluoroethylene and bromotrifluoroethylene; (per)fluoroalkylvinylethers (CF2CFORf); or perfluoro-oxyalkylvinylethers (CF2CFOX). The fluorinated monomer(s) containing sulfonyl groups comprises vinylsulfonylfluoride; F2CFO(CF2CXFO)nCF2CF2SO2F; F2CFOCF2CF2OCF2SO2F; or F2CCFArSO2F.In the polymerization process, co-monomers (0.01-5 mole.%) and bis olefins of formula (II) are used:R1R2CCH(CF2)mCHCR5R6 (II)Rf of CF2CFORf = 1-6C (per)fluoroalkyl, preferably trifluoromethyl, bromo difluoromethyl, pentafluoropropyl;X of CF2CFOX = 1-12C perfluoro-oxyalkyl having ether group(s), preferably perfluoro-2-propoxy-propyl;X of F2CFO(CF2CXFO)nCF2CF2SO2F = Cl, F, or CF3;n of F2CFO(CF2CXFO)nCF2CF2SO2F = 1-10;m = 2-10, preferably 4-8;R1, R2, R5, R6 = 1, 1-5C alkyl.Preferred Method: In the polymerization process, brominated, iodinated cure site co-monomers are fed; alternatively or also in combination with the cure-site co-monomers, it is possible to introduce in the end groups iodine and/or bromine atoms by addition to the reaction mixture of iodinated and/or brominated chain transfer agents or chain transfer agents containing hydrogen, such as hydrocarbons, alcohols, particularly ethyl acetate and ethane.Preferred Property: The sulfonic fluorinated ionomers have an equivalent weight of 300-1700.Preferred Parameter: The polymerization is carried out at 25-130 degreesC, at atmospheric pressure or under pressure, preferably 2-60 bar. It is carried out at preferably 50-60 degreesC at most 30 bar (preferably higher than 8). Preferred Definitions:    Rf = T-(CF2O)a(CF2CF2O)bCF2, T(CF2(CF2))z'CF2O)bCF2, or T(C3F6O)r(C2F4O)b(CFL0O)tCF2;    b/a = 0.3-10;    r/b = 0.5-2;    (r+b)/t = 10-30;    b = t=0;    a, b, b', r, t = integers whose sum is such that Rf has the values of number average molecular weight.    b and t are integers different from 0 when all the units with indexes r, b, and t are present.    EXAMPLE - In an autoclave, 12.5 demineralized water, monomer (980 g) of formula CF2CFOCF2CF2SO2F, and aqueous solution (3100 g) at 5 wt.% fluoropolyoxyalkylene having acid end group potassium salified with number average molecular weight 521, of formula CF2ClO(CF2CF(CF3)O)n, were stirred and heated to 50 degreesC.    An aqueous solution (3 g/l) having a concentration of 28 g/l potassium persulfate (KPS) are fed. The pressure was brought to 12 atmospheres by introducing TFE. The polymer in the sulfonyl chloride was transformed into granules, and transformed in film of 10-400 microm thick. A portion of the film was converted into the acid form by treatment at 80 degreesC for 24 hours with 10 wt.% potassium hydroxide, washing with water, and subsequent treatment at room temperature for 24 hours with 20 wt.% hydrochloric acid, and subsequent washing with water.