Recent Developments in Chain-Growth Polymerizations of Conjugated Polymers

In this Review, we discuss recent developments and advancements in chain-growth polymerizations for conjugated polymers. Controlled synthesis methods will produce conjugated polymers with finely tuned properties and facilitate their development in new industrial applications. We begin with a discussion on the inherent differences between step-growth, chain-growth, and controlled chain-growth polymerization mechanisms. We emphasize that verification of polymerization mechanisms by kinetic analyses is necessary for the development of new controlled polymerizations. Next, we highlight recent advances in this rapidly growing field. Controlled syntheses of conjugated polymers usually employ a catalyst transfer mechanism, but techniques utilizing different controlled mechanisms are also beginning to emerge. We then highlight reported limitations that serve as a platform for future studies. Finally, to emphasize the potential of controlled chain-growth polymerizations, the synthesis of conjugated block copolymers by sequential chain growth reactions is briefly discussed.