Simultaneous Synthesis and Self‐Assembly of Bottlebrush Block Copolymers at Room Temperature via Photoinitiated RAFT Dispersion Polymerization

Abstract Bottlebrush polymers exhibiting unique properties have attracted considerable attention for applications in many research areas. Herein, the first simultaneous synthesis and self‐assembly of bottlebrush block copolymers at room temperature via photoinitiated polymerization‐induced self‐assembly (photo‐PISA) using multifunctional macromolecular chain transfer agents (macro‐CTAs) is reported. Comparing with linear block copolymers, the bottlebrush block copolymers can promote the formation of higher‐order morphologies (e.g., vesicles) when targeting similar degrees of polymerization (DPs). Moreover, a higher polymerization rate is observed in the case of bottlebrush block copolymers. Gel permeation chromatography (GPC) analysis shows that good polymerization control is maintained when synthesizing bottlebrush block copolymers by photo‐PISA. Finally, the obtained bottlebrush block copolymer vesicles are used as seeds for further chain extension and multicompartment nanoparticles with a sponge internal structure are formed. It is expected that this study will not only expand polymer architectures employed in PISA, but also provide a new strategy to synthesize polymer nanoparticles with unique structures.