A series of physical double-network hydrogels is synthesized based on an amphiphilic triblock copolymer. The gel, which contains strong hydrophobic domains and sacrificial dynamic bonds of hydrogen bonds, is stiff and tough, and even stiffens in concentrated saline solution. Furthermore, due to its supramolecular structure, the gel features improved self-healing and self-recovery abilities
Poly(ethylene glycol) (PEG)‐based hydrogels have attracted increasing attention in recent years due to their good biocompatibility and low cost. However, the PEG‐based hydrogels prepared by traditional methods exhibit a poor machinability due to their disordered network structure. Herein, the preparation of well‐defined PEG‐based hydrogel via a facile thermally induced copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction is demonstrated. To accomplish this, thermochemically reduced Cu(I) catalyst is adopted to trigger “click” cross‐linking, resulting in a well‐defined PEG network. The as‐synthesized PEG‐based hydrogel exhibits good mechanical performance with a tensile strength of 2.51 MPa, which is higher than the traditional PEG‐based hydrogels prepared from CuSO4/NaSac‐mediated or CuBr/ligand‐catalyzed CuAAC. Moreover, in vitro cytotoxicity and in vivo porcine subcutaneous implantation tests demonstrate that the as‐synthesized PEG‐based hydrogel has a good biocompatibility and low toxicity, making it a promising candidate for the applications in biomedical devices and tissue engineering.
Amphiphilic poly[poly(ethylene glycol) methyl ether methacrylate]-b -poly(azidopropyl acrylamide) (PPEGMEMA-b -PAzPA) block copolymers are synthesized via a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and a reactive ester-amine reaction. The azido-functionalized PPEGMEMA-b -PAzPA block copolymers can self-assemble into polymeric micelles in an aqueous medium and encapsulate hydrophobic alkynyl-containing manganese(III)porphyrin (MnP) within the core domain. The subsequent in situ copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) leads to the formation of PEGylated-MnP nanoparticles (PEG-MnP NPs). The as-synthesized PEG-MnP NPs are explored as a heterogeneous catalyst for oxidation of cyclohexene in water. The effect of various parameters, such as precursor oxidants, substrate to catalyst loading ratio, and presence of a cocatalyst, is investigated to optimize the oxidation conditions. The catalytic activity of PEG-MnP NPs in water is also compared with that of dissolved MnP in organic solvent.
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