Synthesis, Morphology, and Optical and Electrochemical Properties of Poly(3-hexylthiophene)-b-poly(3-thiophene hexylacetate)

A series of all-conjugated diblock copolythiophenes of poly(3-hexylthiophene)-b-poly(3-thiophene hexylacetate) (P3HT-b-P3THA) were synthesized via modified sequential Grignard metathesis polymerization. The living P3HT was formed first, then reacting with the monomer of P3THA. By using 2-bromo-3-hexyloxycarbonylmethylene-5-iodothiophene instead of dibromo monomer in metal exchange reaction and by controlling the polymerization temperature relatively low at 16–20 °C, the reaction between carboxylate group and Grignard reagent can be minimized and the polymerization can be controlled; low PDI ( 95%), and well-controlled block ratios of block copolymer were obtained. The introduction of carboxylate group in the side chain of one of the monomers, and controlling the side-chain length difference by only three atoms between two monomers, there are profound effects on the optical and electrochemical properties and morphologies of the block copolymers. The electron-withdrawing carboxy...