Patent ID: 8512812

Claim:
A method of preparing a coated substrate having a conductive transparent film comprising the steps: I) polymerizing a 3,4-alkylenedioxythiophene represented by formula (I): wherein R 1 and R 2 together form a C 1-4 -alkylene group which is optionally substituted, wherein the polymerization is performed in the presence of the polyanion by using peroxodisulfuric acid as an oxidizing agent in an aqueous solvent and wherein the pH during polymerization is 1.5 or less and wherein said aqueous solvent is water and said polyanion is a polystyrene sulfonic acid, thereby obtaining aqueous dispersion containing a complex of a poly(3,4-alkylenedioxythiophene) and a polyanion, wherein a dried film of the dispersion with a film thickness of 0.33 μm has a surface resistivity of 150 ohm/square to 920 ohm/square; II) applying a coating composition comprising the aqueous dispersion and a compound selected from the group consisting of water-soluble compounds having an amide group, water-soluble compounds having a hydroxyl group, water-soluble sulfoxides, and water-soluble sulfone on the surface of the substrate and drying the resultant surface.