High-genus multicompartment vesicles evolved from large compound micelles

We report a high-genus multicompartment vesicle (HGMV) that is self-assembled from poly(ethylene oxide)-block-poly(4-azophenyl-(2-carbamoyloxymethyl)ethyl methacrylate) (PEO₄₃-b-PACEMA₁₀). The formation process of these HGMVs was investigated by transmission electron microscopy (TEM), fluorescence spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy and dynamic light scattering (DLS). We found that the HGMVs underwent a series of intermediate states upon gradually increasing water content (C_w) during preparation. The following morphologies were observed: large compound micelles (LCMs) with internal reverse micelles, multicompartment vesicles (MCVs), and HGMVs with perforated holes. These perforated holes were further revealed by TEM after photo-irradiation. This formation mechanism is different from previously reported membrane-bending and vesicle-fusion processes. Overall, we provide a fresh insight into the formation of polymer vesicles with a higher-order nanostructure.