Synthesis of difluoroethyl perfluorosulfonate monomer and its application

The novel difluoroethyl perfluorosulfonate monomer 20 and its application have been developed. The difluoroethyl perfluorosulfonate monomer 20, which was prepared by the reaction of the vinyl sulfonic acid 19 with vinylidene fluoride, was copolymerized with tetrafluoroethylene (TFE) to give the difluoroethyl perfluorosulfonate copolymer 21. The copolymer 21 was easily converted to the perfluorosulfonic acid ionomer 2 in one step by heating and/or alcoholysis. This property of 21 enables the efficient preparation of the polymer solution of 2.