Polymerization-induced self-assembly (PISA) has been established as an efficient method to fabricate polymeric vesicles. In most PISA cases, the formation of vesicles is solely driven by the solvophobic interactions. Besides solvophobic effects, many other noncovalent interactions can also drive/influence self-assembly of block copolymers. In this work, PISA driven by the synergistic effects of solvophobic and aromatic interactions is investigated. 7-(2-Methacryloyloxyethoxy)-4-methylcoumarin (CMA) is selected as a model monomer for RAFT dispersion polymerization to fabricate vesicles with both solvophobic and aromatic interactions existing in the membrane-forming blocks. Controlling vesicular size in the range of sub-100 nm to micrometer in PISA is realized by copolymerization of CMA with three different comonomers (aromatic or not) in various proportions to adjust the intermolecular interactions. Moreover, polymeric tubes with adjustable aspect ratios (from about 2 to 20) are produced by applying the cooperativity of aromatic and solvophobic interactions.

Compared with the post-polymerization cross-linking strategy, in situ cross-linking by divinyl comonomers in polymerization-induced self-assembly (PISA) is a more straightforward and convenient approach to produce structurally stabilized nano-objects. However, cross-linking...

Polymerization-induced self-assembly (PISA) has been demonstrated to be a powerful strategy for producing polymeric nano-objects. Polymeric nanotubes with hollow and anisotropic structures have attracted great interest in materials science. However, according to the theoretical prediction of the packing parameter, polymeric nanotubes are hard to be produced by the self-assembly of block copolymers, which may be due to the lack of directionality of solvophobic interactions. Herein, we demonstrate that aromatic interactions between the solvophobic blocks facilitate the formation of polymeric nanotubes. Polymeric nanotubes with a remarkable length (>11 μm) are generated in the reversible addition−fragmentation chain transfer (RAFT) dispersion polymerization of the aromatic monomer 2-(methacryloyloxy) ethyl anthracene-9-carboxylate (MAEAC) using poly(ethylene glycol) as the macro RAFT agent (PEG 45 -CPADB). When the aromatic interactions of the membrane-forming blocks are weakened by high temperature or copolymerization of MAEAC with a weakly aromatic monomer 2-(methacryloyloxy)ethyl benzoate (MAEB), spherical nano-objects instead of nanotubes tend to be produced. The concentration of polymer chains also plays a vital role in the formation of polymeric nanotubes. The aspect ratio of the polymeric nanotubes can be adjusted by controlling the polymer concentration without varying the polymer composition, and polymeric nanotubes with a larger aspect ratio tend to be generated at higher concentrations of block copolymers. The formation of polymersomes with different aspect ratios for a given polymer provides significant opportunities to investigate the shape-determined performances of the polymersomes while eliminating the influence of polymer composition.

Comprehensive Summary The size and size distribution of polymeric nanoparticles have great impact on their physicochemical and biological properties. Polymerization‐induced self‐assembly (PISA) has been demonstrated to be an efficient method to fabricate various polymeric nanoparticles, among which polymeric vesicles have attracted great interest due to their unique hollow structure. However, polymeric vesicles with relatively broad size distributions and random size are normally formed, which is problematic for many potential applications. Herein, we report the synthesis of polymeric vesicles with low‐polydispersity and controllable size by polymerization‐induced self‐assembly. A mixed macro RAFT agent of three different poly(ethylene glycol) (PEGm‐CPADB) was used to mediate the RAFT dispersion copolymerization of 7‐(2‐methacryloyloxyethoxy)‐4‐methylcoumarin (CMA) and benzyl methacrylate (BzMA), which generated vesicles with low‐polydispersity (< 0.1) and controllable size in the scope of sub‐100 nm. In comparison, RAFT dispersion copolymerization of CMA and BzMA using a single PEG‐CPADB as the macro RAFT agent generated vesicles with adjustable but obviously larger size and broader size distributions (> 0.1). The results demonstrate that the ternary stabilizers play a crucial role in the formation of small and low‐polydispersity vesicles.