Solid polymer electrolyte material, liquid composition, solid polymer fuel cell and fluoropolymer

A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1), wherein the repeating unit based on a fluoromonomer A is represented by the following formula (4):

• wherein s is 0 or 1, each of Rf4, Rf5, Rf6 and Rf7, which may be the same or different, is a fluorine atom or to a C1-5 perfluoroalkyl group (provided that Rf4 and Rf5 may be connected to form a spiro ring when s is 0), and Rf8 is a fluorine atom, a C1-5 perfluoroalkyl group or a C1-5 perfluoroalkoxy group;
• CF2═CF(Rf)jSO2X (1)
• wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR1R2R3R4 (wherein each of R1, R2, R3 and R4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and Rf is a C1-20 polyfluoroalkylene group having a straight chain or branched structure which optionally contains at least one ether oxygen atom.