In this study, we present extensive dissipative particle dynamics simulation studies of bottlebrush copolymers in solution having different grafting sequences: block and random. Distinct morphology of the grafting sequence-controlled bottlebrush copolymer micelles is investigated through backbone chain distribution along with the micelle structure. As a result, bottlebrush block copolymer (BBCP) micelles exhibit backbone chain primarily dependent on length scale of micelle size, while bottlebrush random copolymer (BRCP) exhibits side chain-dependent length scale. We further quantify the dependence of the micelles on the length scale of the backbone chain and side chain using the scaling relationship. We decouple the size of the micelles into core radius and corona thickness, and scaling behavior of these structures is quantitatively explained by the conformation of backbone chains and side chains. Also, the experimental scaling of BBCP and BRCP micelles in water shows consistent results of the sequence-dependent scaling exponents calculated by simulation. This work reveals the scaling behavior of the sequence-controlled graft copolymer micelles which potentially guides how one can modify the solution self-assembled complex micelles by controlling architecture and structure parameters of the bottlebrush copolymer.

We report the synthesis of the amphiphilic diblock copolymer, poly (vinyl phenol)-block-poly (vinyl alcohol), and its reversible formation of invertible core-shell nanoparticles. The diblock copolymer composed of poly (4-vinylphenol) (P4VPh) and poly (vinyl alcohol) (PVA) was prepared by the switchable reversible addition-fragmentation chain transfer polymerization (switchable-RAFT) of 4-acetoxystyrene and vinyl acetate and subsequent acetyl deprotection. The diblock copolymer was soluble in dimethyl sulfoxide (DMSO) but self-assembled into core-shell nanoparticles with the addition of H2O or tetrahydrofuran (THF). The formation and transition of the invertible core-shell system in response to solvent composition was characterized by 1H NMR, dynamic light scattering, and transmission electron microscopy. Interestingly, the fluorescent behavior of the P4VPh block was changed according to the morphological change of core-shell nanoparticle induced by solvent composition. With increasing the H2O content, the P4VPh chains in the DMSO solution collapsed and the diblock copolymers self-assembled to core-shell type micelles. Aggregation of P4VPh chains increased the local concentration of the phenolic group, resulting in fluorescence quenching. However, with the addition of THF to the DMSO solution, the inverted core-shell nanoparticles were formed where segregated P4VPh chains showed fluorescence.

Bioadhesives are becoming an essential and important ingredient in medical science. Despite numerous reports, developing adhesive materials that combine strong adhesion, biocompatibility, and biodegradation remains a challenging task. Here, we present a biocompatible yet biodegradable block copolymer-based waterborne superglue that leads to an application of follicle-free hair transplantation. Our design strategy bridges self-assembled, temperature-sensitive block copolymer nanostructures with tannic acid as a sticky and biodegradable polyphenolic compound. The formulation further uniquely offers step-by-step increases in adhesion strength via heating–cooling cycles. Combining the modular design with the thermal treating process enhances the mechanical properties up to 5 orders of magnitude compared to the homopolymer formulation. This study opens a new direction in bioadhesive formulation strategies utilizing block copolymer nanotechnology for systematic and synergistic control of the material’s properties.

Supramolecular polymerization offers a fascinating opportunity to develop dynamic soft materials by associating monomeric building blocks via noncovalent interactions. We report that polymerization can spontaneously drive the supramolecular polymerization of nanoscale micellar objects. We constructed the patchy micelles via two-step polymerization-induced self-assembly. A horizontal association between the patches results in a 1D supermicellar chain in situ by minimizing the enthalpic penalty of exposing the growing chains to solvent. Its length grows with increasing degree of polymerization, confirming that the supramolecular polymerization was triggered and controlled by polymerization. Our results highlight the observation that (1) the entire self-assembly process of forming, compartmentalizing, and associating the micelles can be driven by polymerization in a concerted manner and that (2) polymerization-induced self-assembly now can use compartmentalized nanoobjects as substrates beyond block copolymer chains. Polymerization-induced supramolecular polymerization could be useful for the autonomous preparation of hierarchical nanostructures.

This study explores hyper-cross-linking of the cores of block copolymer micelles as a means to generate star polymers with a hyper-cross-linked core surrounded by linear corona arms. A solution of poly(methyl methacrylate)-b-polystyrene (MS) was prepared in acetonitrile to form micelles which were reacted with α,α’-dichloro-p-xylene in the presence of FeCl3 to produce core hyper-cross-linked star (CHS) polymers by selective cross-linking of the PS core. A kinetic investigation showed formation of high-molar mass species (>104 kg mol−1) within 1 h of reaction, which supported conversion of individual MS micelles into CHS polymers. We synthesized several CHS polymers by varying the PS core fractions from 20 to 53%. All the polymers possessed discrete spherical cores that were 19–60 nm in diameter and all were highly soluble in organic solvents retaining the CHS architecture. While permanent microporosity was not detected by gas sorption measurements, increased dye uptake of CHS polymer in solution suggests utility of CHS polymers as stable and solution-processible nanocontainers with accessible free volume in the core.

We report polymerization-induced self-assembly via controlled cross-linking copolymerization to produce robust block copolymer micelles with spherical, elongated, and branched shapes. Reversible addition–fragmentation chain transfer (RAFT) copolymerization of styrene and divinylbenzene (DVB) or 1,2-bismaleimidoethane (BMI) as a cross-linker in the presence of a polylactide macro-chain transfer agent (PLA-CTA) was performed in acetonitrile, which is a non-solvent to polystyrene (PS). The addition of the cross-linker accelerates the copolymerization compared to styrene homopolymerization, which leads to the formation of block polymer micelles within a shorter time frame, followed by in situ inter-chain cross-linking. The micelles are virtually identical to the core cross-linked star polymer consisting of a cross-linked polystyrenic core surrounded by a PLA corona. Molecular weights up to more than 1000 kg mol−1 could be obtained with relatively narrow dispersity values (1.1–1.4). In the case of copolymerization with DVB, the micellar morphology changes from spherical to elongated and branched shapes with increasing conversion. The size and morphology of the micelles are retained in a good solvent to PS, suggesting that the in situ cross-linking effectively stabilizes the micellar core. BMI undergoes alternating copolymerization with styrene in the early stage of polymerization and yields spherical micelles exclusively, because the densely cross-linked core seems to prevent further morphological transition.