Co-Assembly of Diblock Copolymers and Molecular Bottlebrushes

Abstract

Co-assembly of multicomponent polymers could promote the evolution of polymer assemblies into high-order nanostructures. The topological architecture of polymers is an important factor to affect their self-assembly behavior; however, the effect of topological architecture on the co-assembly behavior is still not clear. Herein, the aqueous co-assembly of poly(ethylene oxide)-block-polystyrene (PEG-b-PS) block copolymers (BCPs) and molecular bottlebrushes (MBBs) with polystyrene (PS) as side chains was conducted to investigate the effect of topological architecture on the co-assembly behavior. First, well-defined PEG-b-PS BCPs with varying degrees of polymerization (DP) of PEG and PS, and PS MBBs with different lengths (DP) of backbone were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening metathesis polymerization (ROMP), respectively. By varying the DP of PS segments in BCPs and backbone length of MBBs as well as the mass ratio of BCPs and MBBs, various nanostructures ranging from spherical micelles to vesicles and large-compound vesicles (LCVs) were obtained. It was found that the insertion of the PS segment of block copolymers into the side chains of PS MBBs to stabilize MBBs in selective solvents is the key factor for the formation of stable nanometer-sized structures.