Stimuli-responsive hydrogels using dynamic covalent bonds (DCBs) as cross-links may exhibit simultaneously the stimuli-responsibility of the physical gels and stability of the chemical gels. We prepared well-defined, ketone-based polymers based on commercially available diacetone acrylamide (DAAM) by a reversible addition-fragmentation chain transfer (RAFT) polymerization technique. The polymers could react with hexanedihydrazide yielding hydrogels. The mechanics, flexible properties and gelator concentration of the hydrogels can be tuned by varying the ratio of DAAM. Gelation time and hydrogel stability were gravely affected by the pH of the surrounding medium. The hydrogels possess self-healing ability without any external stimuli and undergo switchable sol-gel transition by the alternation of pH. In addition, the hydrogels showed pH-responsive controlled release behavior for rhodamine B. These kinds of ketone-type acylhydrazone DCB hydrogels, avoiding the aldehyde component, may ameliorate their biocompatibility and find potential applications in biomedicines, tissue engineering, etc.

Surface hybrid inorganic semiconductors photocatalysts with π conjugated structure have recently been widely used in the field of photocatalytic environmental remediation and energy conversion. Surface hybridization is considered to be an efficient way to significantly enhance the photocatalytic activity by several times, completely inhibit photocorrosion of inorganic photocatalysts and expand the spectral response range of photocatalysts. This review provides a comprehensive overview of the surface hybridization definition, the principle of enhancing photocatalytic performance and the control factors of surface hybridization to promote photoactivity. Summarize the preparation and structural identification method of the surface hybrid photocatalyst. Special emphasis is placed on the various photocatalytic system construction of surface hybridization. The development of surface hybrid photocatalysts for pollutant degradation and energy conversion are further presented. Finally, the challenges and future development prospects of surface hybridization in photocatalysis are discussed. We hope this critical review can provide a clear picture of the state‐of‐the‐art achievements and facilitate the applications of surface hybrid photocatalysts in environmental remediation and energy conversion.

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Polymer topology exerts a significant effect on its properties and performance for potential applications. Cyclic topology and its derived structures have been recently shown to outperform conventional linear analogues for drug delivery applications. However, an amphiphilic tadpole-shaped copolymer consisting of a cylic hydrophobic moiety has rarely been explored. For this purpose, a tadpole-shaped amphiphilic diblock copolymer of poly­(ethylene oxide)-b-(cyclic poly­(ε-caprolactone)) (mPEG-b-cPCL) was synthesized successfully via ring-opening polymerization (ROP) of ε-CL using a mPEG-based macroinitiator with both a hydroxyl and an azide termini and subsequent intrachain Cu­(I)-catalyzed azide–alkyne cycloaddition (CuAAc) click cyclization. A comparison study on the self-assembly behaviors, in vitro drug loading and drug release profiles, and degradation properties of the resulting mPEG-b-cPCL (C) with those of the linear counterpart (mPEG-b-PCL, L) revealed that mPEG-b-cPCL micelles are a better formulation than the micelles formed by the linear counterparts in terms of micelle stability, drug loading capacity, and the degradation property. Interestingly, compared to the single degradation of L, C exhibited a slower two-stage degradation process including the topological change from tadpole shape to linear conformation and the subsequent degradation of a linear polymer. This study therefore uncovered the topological effect of a hydrophobic moiety on the properties of the self-assembled micelles and developed a complementary alternative to enhance the micelle stability by introducing a cyclic hydrophobic segment.

We reported herein the synthesis of a novel dumbbell-shaped amphiphilic copolymer with two macrocycles-based bells, and revealed the better performance of this polymer construct than those of the linear and tadpole-like analogues for drug release.

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