Adaptive Morphology of Surface-Segregated Micelles Synthesized from Polymerization-Induced Self-Assembly Co-Mediated by a Binary Mixture of Macro-RAFT Agents

Surface-segregated micelles (SSMs) have shown potential applications in drug delivery, bioimaging, and Pickering emulsions due to their adaptive characteristics. A diverse set of SSMs are prepared by reversible addition-fragmentation transfer (RAFT)-mediated polymerization-induced self-assembly (PISA). However, the obtained self-assembled structures are mostly limited to spherical forms, and SSMs with a hierarchical structure are not yet prepared. In this study, SSMs with various hierarchical structures are generated by the dispersion polymerization of benzyl methacrylate (BzMA) co-mediated by a binary mixture of poly(2-(dimethylamino)ethyl methacrylate) and polydimethylsiloxane as macromolecular chain-transfer agents (macro-CTAs). The obtained structures include cylinders, vesicles, large compound micelles, and bundles of hoops. The morphological evolution of these structures and vesicle size can be readily tuned by varying the composition of the binary mixture of macro-CTAs. This study expands the scope of RAFT-mediated PISA for synthesizing well-defined polymer nano-objects with higher-order morphologies for various applications.