Facile topological transformation of ABA triblock copolymers into multisite, single-chain-folding and branched multiblock copolymers via sequential click coupling and anthracene chemistry

Telechelic PtBA-b-PSt-b-PtBA copolymers were designed to achieve on-demand topological transformation into multisite, single-chain-folding and branched multiblock copolymers via click/click-like reactions.

Consequences of Molecular Architecture on the Supramolecular Assembly of Discrete Block Co-oligomers

Supramolecular block copolymers composed of discrete blocks have promising properties for nanotechnology resulting from their ability to combine well-defined morphologies with good bulk material properties. Here, we present the impact of a well-defined siloxane block in either the main-chain or present as pendant grafts on the properties of supramolecular block copolymers that form ordered nanostructures with sub-5 nm domains. For this, two types of supramolecular block copolymers were synthesized based on the ureidopyrimidinone-urethane (UPy-UT) motif. In the first, oligodimethylsiloxanes (oDMS) of discrete length were end-capped with the UPy-UT motif, affording main-chain UPy-UT-Si n . In the second, the UPy-UT motif was grafted with discrete oDMS affording grafted UPy-UT- g -Si 7 . For the two systems, the compositions are similar; only the molecular architecture differs. In both cases, crystallization of the UPy-UT block is in synergy with phase segregation of the oDMS, resulting in the formation of lamellar morphologies. The grafted UPy-UT- g -Si 7 can form long-range ordered lamellae, resulting in the formation of micrometer-sized 2D sheets of supramolecular polymers which show brittle properties. In contrast, UPy-UT-Si n forms a ductile material. As the compositions of both BCOs are similar, the differences in morphology and mechanical properties are a direct consequence of the molecular architecture. These results showcase how molecular design of the building block capable of forming block copolymers translates into controlled nanostructures and material properties as a result of the supramolecular nature of the interactions.

Synthesis of multisegmented block copolymer by Friedel–Crafts hydroxyalkylation polymerization

Friedel–Crafts (FC) polycondensation of 1,4-dimethoxybenzene with 4-substituted benzaldehyde species was used to prepare telechelic oligomers and high-molar-mass multisegmented block copolymers.

Dispersity and architecture driven self-assembly and confined crystallization of symmetric branched block copolymers

Architectural variety in the form of branching combined with disparate dispersities in block polymers have been exploited to access microphase morphologies outside the conventional phase windows typically observed in uniform linear analogs.

Precise Synthesis of Macromolecular Architectures by Novel Iterative Methodology Combining Living Anionic Polymerization with Specially Designed Linking Chemistry

This article reviews the development of a novel all-around iterative methodology combining living anionic polymerization with specially designed linking chemistry for macromolecular architecture syntheses. The methodology is designed in such a way that the same reaction site is always regenerated after the polymer chain is introduced in each reaction sequence, and this "polymer chain introduction and regeneration of the same reaction site" sequence is repeatable. Accordingly, the polymer chain can be successively and, in principle, limitlessly introduced to construct macromolecular architectures. With this iterative methodology, a variety of synthetically difficult macromolecular architectures, i.e., multicomponent μ-star polymers, high generation dendrimer-like hyperbranched polymers, exactly defined graft polymers, and multiblock polymers having more than three blocks, were successfully synthesized.

Facile synthesis of multiarmed and multicomponent star polymers by a new iterative methodology using (formyl-protected 1,3-dioxolane)-end-functionalized polymer anions

In this manuscript, we have developed a new and efficient iterative methodology using formyl-protected 1,3-dioxolane-end-functionalized polymer anions for the facile synthesis of multiarmed and multicomponent miktoarm star polymers.

Synthesis of four- and six-armed star-shaped polycarbonates by immortal alternating copolymerization of CO2 and propylene oxide

A series of four- and six-armed star-shaped poly(propylene carbonate)s (PPCs) have successfully been synthesized by carbon dioxide (CO₂)–propylene oxide (PO) immortal alternating copolymerization initiated either from tetra- or hexa-functional carboxylic acids.

Synthesis and post-polymerization reaction of end-clickable stereoregular polymethacrylates via termination of stereospecific living anionic polymerization

Poly(methyl methacrylate)s with high stereoregularity and clickable end-groups were synthesized via terminating reactions with α-(halomethyl)acrylates in stereospecific living anionic polymerization.

New polymethylene-based AB2 star copolymers synthesized via a combination of polyhomologation of ylides and atom transfer radical polymerization

Polymethylene-based AB₂ star copolymers were synthesized. PM-b-(PS)₂ porous films and particles were fabricated via static breath-figure process and electrospraying, respectively.

Self-assembly and chemical processing of block copolymers: a roadmap towards a diverse array of block copolymer nanostructures

Block copolymers can yield a diverse array of nanostructures. Their assembly structures are influenced by their inherent structures, and the wide variety of structures that can be prepared especially becomes apparent when one considers the number of routes available to prepare block copolymer assemblies. Some examples include self-assembly, directed assembly, coupling, as well as hierarchical assembly, which can yield assemblies having even higher structural order. These assembly routes can also be complemented by processing techniques such as selective crosslinking and etching, the former technique leading to permanent structures, the latter towards sculpted and the combination of the two towards permanent sculpted structures. The combination of these pathways provides extremely versatile routes towards an exciting variety of architectures. This review will attempt to highlight destinations reached by LIU Guojun and coworkers following these pathways.

Anionic Polymerization of para-(1-Ethoxy ethoxy)styrene: Rapid Access to Poly(p-hydroxystyrene) Copolymer Architectures

Living anionic polymerization of para-(1-ethoxy ethoxy)styrene (pEES) resulting in molecular weights between 2700 and 69 000 g mol^-1 and polydispersity indices ≤1.09 is introduced. PpEES can be used as a precursor for the synthesis of well-defined poly(p-hydroxystyrene) (PHS) architectures, enabling facile and rapid acidic deprotection at room temperature within a few minutes. In addition, a series of block copolymers containing pEES and 2-vinylpyridine (2VP) have been synthesized by anionic block copolymerization, with varied block ratios (X_2VP) between 0.13 and 0.83. Characterization by ¹H NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC) was carried out, and all polymers have been deprotected, leading to the respective PHS-b-P2VP block copolymers. Furthermore, PHS-b-P2VP has been used as a macroinitiator for the anionic ring-opening polymerization of ethylene oxide (EO) to generate ((PHS-g-PEO₅₁)₁₃-b-P2VP₄₀) graft-block copolymers.