The synthesis and crosslinking of substituted regioregular polythiophenes

A range of substituted head-to-tail polythiophene random copolymers containing alkyl and ω-hydroxyalkyl side chains has been synthesized by protection of the alcohol as a tetrahydropyranyl acetal during polymerization. The ω-hydroxyl group can be transformed into an azide which, on heating, decomposes and leads to crosslinking which renders the solid polythiophene film insoluble and modifies its optical properties. An ω-hydroxyalkyl homopolymer has also been synthesized by this route and affords polymers with unexpected optical properties.