Process for producing functionalized polythiophenes

A liquid composition having a pH-value in the range from 6 to 8 and comprising an alkali metal hydroxide and a functionalized π-conjugated polythiophene that is dissolved or dispersed in a solvent, wherein the polythiophene comprises repeating units of the general formula (I):

• wherein X, Y are identical or different and are O, S, or NR1, wherein R1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms;
• A is an organic residue carrying an anionic functional group;
• and wherein a composition that is obtained after drying the liquid composition at a temperature of 100° C. and a pressure of 50 mbar for 16 hours, fulfills at least one of the following conditions (A) to (E):
• (A) a weight loss of 10 wt.-%, based on the total weight of the dried liquid composition, at a temperature of not less than 300° C. as determined by means of thermogravimetric analysis;
• (B) a weight loss of 20 wt.-%, based on the total weight of the dried liquid composition, at a temperature of not less than 330° C. as determined by means of thermogravimetric analysis;
• (C) a weight loss of 30 wt.-%, based on the total weight of the dried liquid composition, at a temperature of not less than 345° C. as determined by means of thermogravimetric analysis;
• (D) absence of a peak in a derivative plot of weight versus time from a thermogravimetric analysis in the interval between 250° C. and 270° C.;
• (E) a ratio of a derivative value at 261° C. to the derivative value at a 2nd peak of 0.01 or less.

A liquid composition comprising a liquid phase comprising a functionalized π-conjugate polythiophene that is dissolved or dispersed in a solvent,

• wherein the functionalized π-conjugate polythiophene comprises repeating units of the general formula (I):
• wherein
• X, Y are identical or different and are O, S, or NR1, wherein R1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms;
• A is an organic residue carrying an anionic functional group;
• and wherein the liquid phase comprises an alkali metal hydroxide and has a pH value in the range from 6 to 8.