Electrolyte membrane-forming liquid curable resin composition, and preparation of electrolyte membrane and electrolyte membrane/electrode assembly

A liquid curable resin composition comprising a compound having an ethylenically unsaturated group and an ion conductive group and optionally, an oligomer having at least two reactive groups is cured by heat and/or UV or EB irradiation to form an electrolyte membrane having excellent ionic conduction. The composition has a viscosity of 100-100,000 mPa·s at 25°C so that it is readily applicable. The electrolyte membrane and an electrolyte membrane/electrode assembly for use in fuel cells satisfy cell-related properties including ionic conduction and film strength as well as productivity.