Two new bis(perfluoroalkyl)arylsulfonyl imide monomers, which contain the aryl diazonium moiety and intramolecular zwitterionic fragment, have been designed and prepared for the first time from perfluoro(3-oxa-4-pentene)sulfonyl fluoride. As promising monomer candidates for high-performance proton exchange membrane fuel cell electrolytes, these two monomers have furnished perfluorinated electrolytes that include the polymers from perfluorinated sulfonic acid or perfluorinated sulfonimide monomers. The synthesis strategies and NMR analysis are summarized and discussed in details.

Two diazonium perfluoroalkyl arylsulfonimide (PFSI) zwitterionic monomers, 4-diazonium perfluoro(3-oxapent-4-ene)benzenesulfonimide (I) and 4-(trifluoromethyl)-2-diazonium perfluoro(3-oxapent-4-ene)benzenesulfonimide (II) have been synthesized from perfluoro(3-oxapent-4-ene) sulfonyl fluoride (POPF) for proton exchange membrane fuel cells. PFSI polymers are proposed as new electrolytes due to their better thermal stability, inertness to electrochemical conditions, and lower susceptibility to oxidative degradation and dehydration. For a better integration between the electrode and the electrolyte, the PFSI polymers are expected to be grafted onto the carbon electrode via the diazonium moiety. All the reaction intermediates and the final product were characterized with 1H NMR, 19F NMR and IR spectroscopies.