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The self-assembly behavior of poly(gamma-benzyl-L-glutamate)-graft-poly(ethylene glycol) rod-coil graft copolymers in aqueous solution was investigated. With tetrahydrofuran (THF) as initial solvent, vesicles were observed for the graft copolymers with lower degree of grafting. When the degree of grafting increases, the aggregate morphology transforms from vesicles to spindle-like micelles then to spherical micelles. When N,N'-dimethylformamide (DMF) is introduced into the initial solvent, the vesicles transform to spindles. Increasing DMF volume fraction leads to a spindle to connected-spindle transition. On the basis of the experimental results, the mechanism of the morphological transition of the rod-coil graft copolymer is suggested.

Summary: Self‐association behaviors of poly(γ‐benzyl L‐glutamate)‐graft‐poly(ethylene glycol) (PBLG‐graft‐PEG) and its mixtures with PBLG homopolymer in aqueous media were investigated by fluorescence spectroscopy, transmission electron microscopy (TEM), and nuclear magnetic resonance (NMR) spectroscopy. It was revealed that PBLG‐graft‐PEG could self‐assemble to form polymeric micelles with a core‐shell structure in the shape of spindle. The introduction of PBLG homopolymer not only decreases the critical micelle concentration, but also changes the morphology of the micelles.The excitation fluorescence spectra of pyrene as a function of concentrations for the mixture of PBLG‐graft‐PEG with PBLG and a TEM image of the formed micelles.imageThe excitation fluorescence spectra of pyrene as a function of concentrations for the mixture of PBLG‐graft‐PEG with PBLG and a TEM image of the formed micelles.

Toroids and helices are fundamental geometrical structures in nature. Polymers can self‐assemble into various nanostructures, including both toroids and helices; however, nanostructures combining toroidal and helical morphologies (that is, helical toroids) are rarely observed. A binary system is reported containing polypeptide homopolymer and its block copolymer, which can hierarchically self‐assemble into uniform helical nanotoroids in solution. The formation of the helical toroids is a successive two‐step process. First, the homopolymers aggregate into fibrils and convolve into toroids, thereby resembling the toroidal condensation of deoxyribonucleic acid (DNA) chains. Second, the block copolymers self‐assemble on the homopolymer toroids and result in helical surface patterns. Additionally, the chirality of the surface helical patterns can be varied by the chirality of the polypeptide block copolymers.

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The self-assembly of colloidal nanoparticles is conceptually analogous to the polymerization of reactive monomers in molecular systems. However, less is known about the polymerization of colloidal nanoparticles into supracolloidal polymers. Herein, using coarse-grained molecular dynamics and theoretical analysis, we reveal the self-assembly mechanism and kinetics of colloidal nanoparticles constructed from triblock terpolymers. The results show that the formation pathway of supracolloidal polymers involves monomer condensation and oligomer coalescence through the manner of end-to-end collisions. In contrast to the polymerization kinetics of molecular systems, the simulations and theoretical analysis definitely demonstrate that the growth of supracolloidal polymers obeys diffusion-controlled step-growth polymerization kinetics with a variable rate coefficient, where the growth rate is dependent upon the concentration of colloidal nanoparticles and the molecular information of triblock terpolymers. Our findings possess wide implications for understanding the growth of supracolloidal polymers, which is important for the rational and precise design of one-dimensional self-assembled superstructures with new horizons for biomedical applications.