Patent ID: 8399148

Claim:
A varnish incorporated into a solid polymer electrolyte fuel cell which comprises a solvent and an electrode electrolyte for a solid polymer fuel cell electrolyte, comprising a polymer with a structure having a main chain including a polyphenylene, a side chain including a sulfonic acid group and a repeating structural unit represented by formula (C) as a side chain including a nitrogen-containing heterocyclic group wherein Z is at least one structure selected from the group consisting of a direct bond, —O— and —S—, Y represents at least one kind of structure selected from the group consisting of —CO—, —SO 2 —, —SO—, —CONH—, —COO—, —(CF 2 ) l — wherein l is an integer of 1 to 10, and —C(CF 3 ) 2 — and R 20 represents a nitrogen-containing heterocyclic group, q representing an integer of 1 to 5 and p representing an integer of 0 to 4, wherein the solvent is at least one solvent selected from water, alcohols, ethers, ketones, esters, aprotic polar solvents and hydrocarbon solvents, and the solvent is used at 5 to 95% by weight in terms of the weight ratio.