The Synthesis of Poly(thiophene-co-fluorene) Gradient Copolymers

The copolymerization of thiophene and fluorene starting from a mixture of the two monomers is investigated. It is shown that these monomers are incapable of copolymerizing using a Kumada catalyst transfer polycondensation. However, when the Pd(RuPhos) protocol is used, this copolymerization is enabled and gradient copolymers are obtained. Consequently, this protocol is applied to the synthesis of a series of six polymers with varying monomer feeds, and the properties of these gradient copolymers are investigated. This new class of materials, which was previously inaccessible using other catalysts, shows unique properties compared with the block copolymer analogues.