Process for producing functionalized polythiophenes
A process for producing a liquid composition comprising a functionalized π-conjugated polythiophenes, comprising the process steps of i) providing a liquid phase comprising a functionalized π-conjugated polythiophene that is dissolved or dispersed in a solvent, wherein the functionalized π-conjugated polythiophene comprises repeating units 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 an organic residue carrying an anionic functional group; and wherein the liquid phase has a pH-value of less than 2.5; ii) adjusting the pH-value of the liquid phase provided in process step i) to a value in the range from 2.5 to 10 by the addition of a base. The present invention also relates to a liquid composition obtainable by this process.
1 . A liquid composition comprising functionalized π-conjugated polythiophenes obtained by a process comprising the steps of:
i) providing a liquid phase comprising a functionalized π-conjugated polythiophene that is dissolved or dispersed in a solvent, wherein the functionalized π-conjugated polythiophene comprises repeating units 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 an organic residue carrying an anionic functional group; and wherein the liquid phase has a pH-value of less than 2.5; and
ii) adjusting the pH-value of the liquid phase provided in process step i) to a value in the range from 6 to 8 by adding an alkali metal hydroxide.
2 . 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 NR 1 , wherein R 1 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 2 nd peak of 0.01 or less.
3 . 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 NR 1 , wherein R 1 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.