Synthesis and morphology characterization of broad dispersity P2VP-b-PS diblock copolymer

Abstract

The structure of the block copolymer has potentials in various nanotechnology and polydispersity is one of the key parameters for the formation. Meanwhile, there was one study that the polydispersity effect stabilizes complex morphologies in the diblock copolymer but there are limitations in clearly demonstrating it. In this study, poly(2-vinylpyridine)-b-polystyrene (P2VP-b-PS) which has strong segregation strength was synthesized and the morphology change induced by the polydispersity effect was experimentally clarified. The polydispersity of the P2VP block was tailored by modifying the controlled radical polymerization and the morphology of the diblock copolymer having P2VP as the major block was characterized by small angle X-ray scattering. When both the blocks were relatively lower polydisperse, the phase transition from lamella to hexagonally packed cylinder occurred. On the other hand, as the extent of asymmetry of the block dispersity between PS and P2VP increases, lamella phase was transited to disordered bicontinuous phase rather than cylinder.