Multifunctional hydrogels acting as wound dressing have received extensive attention in soft tissue repair; however, it is still a challenge to develop a non-antibiotic-dependent antibacterial hydrogel that has tunable adhesion and deformation to achieve on-demand removal. Herein, an asymmetric adhesive hydrogel with near-infrared (NIR)-triggered tunable adhesion, self-deformation, and bacterial eradication is designed. The hydrogel is prepared by the crosslinking polymerization of N-isopropylacrylamide and acrylic acid, during the sedimentation of conductive PPy-PDA nanoparticles based on the polymerization of pyrrole (Py) and dopamine (DA). Due to the conversion capacity from NIR light into heat for PPy-PDA NPs, the formed temperature-sensitive hydrogel exhibits tissue adhesive as well as NIR-triggered tunable adhesion and self-deformation property, which can achieve an on-demand dressing refreshing. Systematically in vitro/in vivo antibacterial experiments indicate that the hydrogel shows excellent disinfection capability to both Gram-negative and Gram-positive bacteria. The in vivo experiments in a full-layer cutaneous wound model demonstrate that the hydrogel has a good treatment effect to promote wound healing. Overall, the asymmetric hydrogel with tunable adhesion, self-deformation, conductive, and photothermal antibacterial activity may be a promising candidate to fulfill the functions of adhesion on skin tissue, easy removing on-demand, and accelerating the wound healing process.

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a b s t r a c tIn this paper, we consider a two-sided space-fractional diffusion equation with variable coefficients on a finite domain. Firstly, based on the nodal basis functions, we present a new fractional finite volume method for the two-sided space-fractional diffusion equation and derive the implicit scheme and solve it in matrix form. Secondly, we prove the stability and convergence of the implicit fractional finite volume method and conclude that the method is unconditionally stable and convergent. Finally, some numerical examples are given to show the effectiveness of the new numerical method, and the results are in excellent agreement with theoretical analysis.

Big volume changes, the shuttle effect, and poor conductivity are well‐known, critical issues of sulfur electrodes that prevent practical application of lithium‐sulfur batteries. The design of active materials with a conductive shell provides an effective solution. Traditional strategies have long been limited for practical applications; however, by low productivity and time/energy consuming template‐based methods. Here, a facile template‐free self‐caging nanotechnology for the scalable fabrication of graphene@sulfur nanocages with atomic‐scale shells is reported. To do that, a new sulfur‐graphene nanochemistry based on a reductive sulfur solution and oxidative sulfonated‐graphene dispersion is developed for the first time. With only the help of mechanical mixing, sulfur particles are successfully synthesized in situ and encapsulated into reaction‐induced self‐assembled sulfonated‐graphene nanocages. These unique nanocages not only provide accommodation of the big volume changes in the active materials, but also exhibit robust polysulfide trapping capability due to the synergistic effects from physical blocking and strong chemical absorption. As a result, the resultant sulfur cathodes deliver superior electrochemical performance and have shown an extremely slow capacity decay of 0.019% per cycle at 0.5 C for over 2000 cycles. This study introduces a new self‐caging nanochemistry for scalable synthesis of functional nanocages with significant applications beyond lithium‐sulfur batteries.

In recent years, non-Newtonian fluids have received much attention due to their numerous applications, such as plastic manufacture and extrusion of polymer fluids. They are more complex than Newtonian fluids because the relationship between shear stress and shear rate is nonlinear. One particular subclass of non-Newtonian fluids is the generalized Oldroyd-B fluid, which is modelled using terms involving multi-term time fractional diffusion and reaction. In this paper, we consider the application of the finite difference method for this class of novel multi-term time fractional viscoelastic non-Newtonian fluid models. An important contribution of the work is that the new model not only has a multi-term time derivative, of which the fractional order indices range from 0 to 2, but also possesses a special time fractional operator on the spatial derivative that is challenging to approximate. There appears to be no literature reported on the numerical solution of this type of equation. We derive two new different finite difference schemes to approximate the model. Then we establish the stability and convergence analysis of these schemes based on the discrete H 1 norm and prove that their accuracy is of O(τ +h 2 ) and O(τ min{3−γs,2−αq,2−β} +h 2 ), respectively. Finally, we verify our methods using two numerical examples and apply the schemes to simulate an unsteady magnetohydrodynamic (MHD) Couette flow of a generalized Oldroyd-B fluid model. Our methods are effective and can be extended to solve other non-Newtonian fluid models such as the generalized Maxwell fluid model, the generalized second grade fluid model and the generalized Burgers fluid model.

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