PROCESS FOR PRODUCING FUNCTIONALIZED POLYTHIOPHENES

The present invention relates to a process for producing a liquid composition comprising a functionalized À-conjugated polythiophenes, comprising the process steps of i) providing a liquid phase comprising a) thiophene monomers of the general formula (I) wherein X,Y are identical or different and are O, S, or NR 1 , wherein R 1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms; A is organic residue carrying an anionic functional group; b) an oxidizing agent; and c) a solvent; ii) oxidatively polymerizing the thiophene monomers of the general formula (I) to obtain a liquid composition comprising functionalized À-conjugated polythiophenes; wherein (±1) the pH of the liquid phase provided in process step i) is adjusted to a value below 7.0, wherein the pH is determined at a temperature of 20°C; and (±2) the chloride content of the liquid phase provided in process step i) is less than 10,000 ppm, based on the total weight of the liquid phase. The present invention also relates to the liquid composition obtainable by this process, to a process for the preparation of a capacitor in which this liquid composition is used for the formation of the solid electrolyte, to a capacitor obtainable by this process and to the use of the liquid composition for the preparation of a conductive layer.