Patent ID: 7122130

Claim:
A method for preparing a composition comprising between 0.08 and 3.0% by weight of a polymer or copolymer of a 3,4-dialkoxythiophene in which said two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and at least one non-aqueous solvent from a dispersion of said polymer or copolymer of (3,4dialkoxythiophene) and said polyanion in water, the method comprising in the following order the steps of: (i) mixing at least one of said non-aqueous solvents with said aqueous dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion; and (ii) evaporating water from the mixture prepared in step (i) until the content of water therein is reduced by at least 65% by weight; wherein said method further comprising preparing said dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and polyanion in water under an inert gas.