Patent ID: 7378039

Claim:
An aqueous or non-aqueous solution or dispersion of a polythiophene or thiophene copolymer obtained by a process for preparing an aqueous or non-aqueous solution or dispersion of a polythiophene or thiophene copolymer comprising structural units according to formula (I): in which R 1 and R 2 independently of one another represent hydrogen or a C 1-5 -alkyl group or together form an optionally substituted C 1-5 -alkylene residue, the process comprising the steps of: preparing the polythiophene or thiophene copolymer using an initiator in a reaction medium in the presence of polyanions under oxidizing or reducing conditions under an inert atmosphere such that when said initiator is added less than 3 mg of oxygen per liter of said reaction medium is present in said reaction medium and preparing an aqueous or non-aqueous solution or dispersion of the polythiophene or thiophene copolymer.