Polymer solution, the conductive polymer film and a solid electrolytic capacitor obtained from the polymerization solution

In the polymerization solution for electrolytic polymerization comprising borodisalicylate acid and / or its salt as a supporting electrolyte, to suppress the precipitation by hydrolysis of borodisalicylate acid ions, to provide a polymer liquid to provide a highly heat-resistant conductive polymers . The polymerization solution of the present invention, a solvent consisting of 100 to 80 wt% of water and 0 to 20 wt% of an organic solvent, at least one monomer having a π- conjugated double bonds, borodisalicylate acid and borodisalicylate acid comprising at least one supporting electrolyte selected from the group consisting of salt, and at least one stabilizer selected from the group consisting of nitrobenzene and nitrobenzene derivatives, a polymer solution for electrolytic polymerization of the monomers, the content of the stabilizer, characterized in that more than 1/8 moles with respect to the supporting electrolyte 1 mol. The complex with a stabilizer and a borodisalicylate acid is formed, precipitation by hydrolysis of borodisalicylate acid ions is suppressed.