TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The vinyl ether monomers having sulfonyl-fluoride-containing short pendant groups is 1,1,2,2-tetrafluoro-2-((trifluorovinyl)oxy)ethanesulfonyl fluoride and 1,1,2,2,3,3,4,4-octafluoro-4-((trifluorovinyl)oxy)butane-1-sulfonyl fluoride. The vinyl ether monomer having cyano-containing pendant group is of formula: (F2C=CF-O-(CF2-CF(-CF3)-O-)n-CF2-CF2-P(=O)(-O)-O-).2M+. The reaction initiator is dinitrogen difluoride, perfluoroalkyl peroxide, and/or persulfate. The perfluoroalkyl peroxide is perfluoroalkyl acyl peroxide compound, perfluoroalkoxy acyl peroxide compound, fluorinated alkyl acyl peroxide compound and/or fluorinated alkoxy acyl peroxide compound. The persulfate is ammonium persulfate, alkali metal persulfide, and/or alkaline-earth metal persulfide. The perfluoroalkyl peroxide is perfluoropropionyl peroxide, 3-chlorofluoropropionyl peroxide, perfluoromethoxy acetyl peroxide, omega -H-perfluorobutyryl peroxide, omega -SO2F-perfluorinated-2,5,8-trimethyl-3,6,9-trioxaundecyl peroxide, CF3CF2CF2CO-OO-COCF2CF2CF3, CF3CF2CF2OCFCF3CO-OO-COCFCF3OCF2CF2CF3, CF3CF2CH2CO-OO-COCH2CF2CF3 and/or CF3OCF2CF2CO-OO-COCF2CF2OCF3. The persulfate is ammonium persulfate and/or potassium persulfate. The copolymerization is emulsion polymerization reaction in aqueous phase. In emulsion polymerization, the emulsifier is one or more non-ionic emulsifiers chosen from alkylphenol polyether polyol, nonylphenol polyoxyethylene ether, polyoxyethylene fatty acid and polyoxyethylene fatty acid ether. In emulsion polymerization reaction, the mass concentration of emulsifier in emulsion polymerization is 0.1-10%, preferably 1-8%, mass concentration of vinyl ether monomers having sulfonyl-fluoride-containing short pendant groups is 5-30%, preferably 5-20%, and mass concentration of vinyl ether monomer having phosphonate pendant group is 1-12%, preferably 5-10%.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The total molar fraction of tetrafluoroethylene polymerization unit is 50-85%, preferably 70-80%, total molar fraction of polymerization unit of vinyl ether monomers having sulfonyl-fluoride-containing short pendant groups is 5-49%, preferably 15-29%, and total molar fraction of polymerization unit of vinyl ether monomer having cyano-containing pendant group is 1-10%, preferably 1-5%. The molar ratio of two kinds of vinyl ether monomers having sulfonyl-fluoride-containing short pendant groups is 0.25-4, preferably 0.6-1.5.