Patent ID: 7008562

Claim:
A process for preparing a dispersion or a solution containing a polythiophene + An − ion complex in an organic solvent, the process comprising the consecutive steps of: a) adding a water-miscible organic solvent or a water-miscible organic solvent mixture to an aqueous dispersion or a solution of a polythiophene + An − ion complex, wherein the polythiophene + is a polymer comprising recurring units represented by formula (I) at least some of which are positively charged and wherein Y is —(CH 2 ) m —CR 1 R 2 (CH 2 ) n — or an optionally substituted 1,2-C 3 –C 8 -cycloalkylene radical, and R 1 and R 2 , independently of one another, are hydrogen, hydroxymethyl, an optionally substituted C 1 –C 20 -alkyl radical or an optionally substituted C 6 –C 14 -aryl radical, and m and n are identical or different and are an integer from 0 to 3, and wherein An − is an anion of an organic polyacid, or wherein the polythiophene + An − is a polymer comprising recurring units represented by formula (II) wherein at least some of the thiophene rings carry a positive charge and wherein Z is —(CH 2 ) m —CR 3 R 4 (CH 2 ) n —, R 3 is hydrogen or —(CH 2 ) s —O—(CH 2 ) p —SO 3 − M + , R 4 is —(CH 2 ) s —O—(CH 2 ) p —SO 3 − M + , m and n are an integer from 0 to 3, M + is a cation, s is an integer from 0 to 10, and p is an integer from 1 to 18; and b) removing water from the mixture resulting in step a), thereby forming the dispersion or the solution, wherein in step (b) water is removed from the mixture by means of a membrane process.