It is to provide a membrane/electrode assembly excellent in the power generation characteristics under low or no humidity conditions and under high humidity conditions, and an electrolyte material suitable for a catalyst layer of the membrane/electrode ass...

The present invention relates to a method for producing a fluorocopolymer which comprises a polymerization reaction of a fluorine-containing ethylenic monomer with a fluorovinyl ether derivative represented by the following general formula (I): CF2=CF-O-Ä...