掲載種別：研究論文（学術雑誌）   出版者・発行元：Royal Society of Chemistry (RSC)  

With optimized synthesis, slide-ring polycatenane networks exhibit distinct swelling and viscoelasticity arising from ring motion. Simulations elucidate these mechanisms, and ring mobility effects are revealed through metalation and protonation.

DOI： 10.1039/d5sc05459a

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

<jats:title>Abstract</jats:title><jats:p>The integration of mechanically interlocked molecules (MIMs) into polymeric materials has led to the development of mechanically interlocked polymers (MIPs). One class of MIPs that have gained attention in recent years are slide‐ring gels (SRGs), which are generally accessed by crosslinking rings on a main‐chain polyrotaxane. The mobility of the interlocked crosslinking moieties along the polymer backbone imparts enhanced properties onto these networks. An alternative synthetic approach to SRGs is to use a doubly threaded ring as the crosslinking moiety, yielding doubly threaded slide‐ring gel networks (dt‐SRGs). In this study, a photo‐curable ligand‐containing thread was used to assemble a series of metal‐templated pseudo[3]rotaxane crosslinkers that allow access to polymer networks that contain doubly threaded interlocked rings. The physicochemical and mechanical properties of these dt‐SRGs with varying size of the ring crosslinking moieties were investigated and compared to an entangled gel (EG) prepared by polymerizing the metal complex of the photo‐curable ligand‐containing thread, and a corresponding covalent gel (CG). Relative to the EG and CG, the dt‐SRGs exhibit enhanced swelling behavior, viscoelastic properties, and stress relaxation characteristics. In addition, the macroscopic properties of dt‐SRGs could be altered by “locking” ring mobility in the structure through remetalation, highlighting the impact of the mobility of the crosslinks.</jats:p>

DOI： 10.1002/ange.202411172

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

<jats:title>Abstract</jats:title><jats:p>Supramolecular polymers, in which monomers are assembled via intermolecular interactions, have been extensively studied. The fusion of supramolecular polymers with conventional polymers has attracted the attention of many researchers. In this review article, the recent progress in the construction of supramolecular star polymers, including regular star polymers and miktoarm star polymers, is discussed. The initial sections briefly provide an overview of the conventional classification and synthesis methods for star polymers. Coordination‐driven self‐assembly was investigated for the supramolecular synthesis of star polymers. Star polymers with multiple polymer chains radiating from metal‐organic polyhedra (MOPs) have also been described. Particular focus has been placed on the synthesis of star polymers featuring supramolecular cores formed through hydrogen‐bonding‐directed self‐assembly. After describing the synthesis of star polymers based on host‐guest complexes, the construction of miktoarm star polymers based on the molecular recognition of coordination capsules is detailed.</jats:p>

DOI： 10.1002/cplu.202400014

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

<jats:title>Abstract</jats:title><jats:p>Vinylogous urethane (VU<jats:sub>O</jats:sub>) based polymer networks are widely used as catalyst‐free vitrimers that show rapid covalent bond exchange at elevated temperatures. In solution, vinylogous ureas (VU<jats:sub>N</jats:sub>) undergo much faster bond exchange than VU<jats:sub>O</jats:sub> and are highly dynamic at room temperature. However, this difference in reactivity is not observed in their respective dynamic polymer networks, as VU<jats:sub>O</jats:sub> and VU<jats:sub>N</jats:sub> vitrimers prepared herein with very similar macromolecular architectures show comparable stress relaxation and creep behavior. However, by using mixtures of VU<jats:sub>O</jats:sub> and VU<jats:sub>N</jats:sub> linkages within the same network, the dynamic reactions can be accelerated by an order of magnitude. The results can be rationalized by the effect of intermolecular hydrogen bonding, which is absent in VU<jats:sub>O</jats:sub> vitrimers, but is very pronounced for vinylogous urea moieties. At low concentrations of VU<jats:sub>N</jats:sub>, these hydrogen bonds act as catalysts for covalent bond exchange, while at high concentration, they provide a pervasive vinylogous urea ‐ urethane (VU) network of strong non‐covalent interactions, giving rise to phase separation and inhibiting polymer chain dynamics. This offers a straightforward design principle for dynamic polymer materials, showing at the same time the possible additive and synergistic effects of supramolecular and dynamic covalent polymer networks.</jats:p>

DOI： 10.1002/anie.202318412

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

<jats:title>Abstract</jats:title><jats:p>We report a new synthetic method to construct supramolecular A<jats:sub>8</jats:sub>B<jats:sub><jats:italic>n</jats:italic></jats:sub> (<jats:italic>n</jats:italic>=1, 2, 4) miktoarm star copolymers by host‐guest complexation between a resorcinarene‐based coordination capsule possessing eight polystyrene chains and 4,4‐diacetoxybiphenyl guest molecules that retain one, two or four polymethyl acrylate chains. The formation of the supramolecular A<jats:sub>8</jats:sub>B<jats:sub><jats:italic>n</jats:italic></jats:sub> (<jats:italic>n</jats:italic>=1, 2, 4) miktoarm star copolymers was confirmed by dynamic light scattering (DLS), size‐exclusion chromatography (SEC), and diffusion‐ordered NMR spectroscopy (DOSY). Differential scanning calorimetry (DSC) measurements revealed that the miktoarm copolymers were phase‐separated in the bulk. The micro‐Brownian motion of the A<jats:sub>8</jats:sub>B<jats:sub>4</jats:sub> structure was markedly enhanced in the bulk due to a weak segregation interaction between the immiscible arms.</jats:p>

DOI： 10.1002/anie.202219001

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