Studies on the Properties of Poly(3-alkylthiophene) Copolymerized by a Small Amount of Thiophene Derivative Bearing a Cyclic Siloxane Moiety at the Side Chain

Thiophene-thiophene copolymers composed of 3-alkylthiophene and a small amount of thiophene bearing cyclic siloxane are synthesized by random copolymerizatin of 2-chloro-3-dodecylthiophene and 2-chlorothiophene bearing cyclic tetrasiloxane as a substituent. Deprotonative metalation of chlorothiophenes with a bulky magnesium amide followed by the addition of nickel catalyst undergoes polymerization to afford statistical copolymer based on the feed ratio. The copolymer bearing a small amount of (1-10%) cyclic siloxane is subjected to the formation of thin film. The treatment of the obtained thin film with an acid vapor results in the formation of film insoluble in any solvent through the formal networking of poly(3-dodecylthiophene) by the effect of a small amount of cyclic siloxane moiety. The measurement of electric properties reveals improved conductivities to 10(6) fold higher than before the acid treatment.