Long‐active conductivity, adhesiveness, and environmental stability are essential in the applications of hydrogel electronics. Integrating different functional materials into one system suffers from compatibility and cost problems. Inspired by the unique o‐methoxyl structure in polyphenol lignin and its binding role in plants, catechol lignin (DAL) is constructed by one‐step demethylation, which endows the lignin with a mussel‐like bioadhesion, good reducibility, as well as a high ultraviolet absorption. The DAL is then applied to reduced graphene oxide, and the products—the oxidized DAL and the reduced graphene oxide mixture (DAL/rGO) is added into a sodium alginate/polyacrylamide (SA/PAM) double network hydrogel. Based on the Schiff base reaction between the quinone of the oxidized DAL and the amino of the skin, the DAL/rGO incorporated hydrogels could stably adhere to the skin, and sensitively respond to physiological signals. In addition, the DAL could provide the hydrogels with long‐active sunscreen property when applied to real skin. These DAL based hydrogels have potential for on‐skin sensing and outdoor sport equipment.

Various synthetic and bioinspired, linear, and 3D network polymeric binders have been developed to suppress the shuttle effect and improve the cyclability of Li-S batteries. [10][11][12][13][14][15] Synthetic binders, such as polyvinylidene fluoride (PVDF), bind conductive materials (carbon black and super P) well via hydrophobic interaction, but they usually show poor adhesion with active materials (S/Li 2 S n ). [16,17] As a comparison, bio-derived binders with functional groups, such as hydroxyl, carboxyl, and amino groups, show the excellent dispersing property to active materials due to the strong dipolar/hydrogen bonding interaction, [13,15,18,19] but the weak interaction with conductive materials still impede their application for sulfur cathodes. In addition, these bio-derived polymer binders are mostly watersoluble (hydrophilic), while the conductive additives are hydrophobic, which is the main obstacle to their interactions. [16,20,21] Few binders match both of the above two binders, and the poor dispersibility of their mixtures usually causes severe aggregation, which makes binders hardly play the role unless the dosage achieves as high as 10 wt% or even in an extreme case of 20 wt%. [22][23][24] Excessive binders in electrodes will limit the battery's energy density and significantly increase the bulk resistance of the whole battery. [21,25,26] In addition, most binders show poor adhesion between active/conductive mixture and current collector, especially after electrolyte wetting, which further increases binder usage. [27] It is urgent to develop binders with broad-spectrum and strong adhesion and good dispersibility to reduce dosages, such as ≤2 wt% as that in commercial Li-S batteries, and improve sulfur utilization, as well as electrochemical stability, and then inspire the theoretical specific energy and high rate performance of Li-S batteries.Fortunately, nature gives us solutions to address previously mentioned issues. As the second most abundant component in plants, lignin is a unique aromatic polymer composed of three p-hydroxyphenylpropane units connected by CO and CC bonds. [28][29][30] Lignin not only binds cellulose with hemicellulose via hydrogen bonding but also plays important role in stress resistance based on its macromolecular aromatic skeleton. [31,32] The distribution and role of lignin in plants are almost the same as those of binders in the cathode of Li-S batteries, which makes lignin an ideal binder candidate for Li-S batteries (Figure 1). Lignin can absorb active materials through carboxyl and hydroxyl groups, interact with conductive additives via the aromatic rings, and constrain the shuttle effect Polymeric binders stabilize lithium-sulfur (Li-S) batteries by suppressing the shuttle of lithium polysulfide (LiPS) and volume variation, but the dosage of state-of-the-art binders in sulfur cathodes (≈20 wt%) hinders the electron/ion transfer and decreases the cell-specific density. Here, a wood-inspired lignin binder is developed after modification with amino acids for pract...

No abstract

This paper reports the wind pressure characteristics on long-span roofs under fluctuating wind in a vertical direction based on a large eddy simulation (LES). Three types of roofs, i.e., saddle, wavy, and continuous arch roofs, are tested. First, the membrane structure canopy is measured, and the model is established for numerical simulation. The computational models and methods are verified by comparing the obtained wind pressure distributions on the roof with the measured results and numerical simulation results under other methods. Next, a numerical simulation is performed to understand not only the wind pressure and the wind speed time series but also the wind vibration responses and fluid-solid coupling. The effects of lateral fluctuating wind at different wind speeds on the wind-induced vibration response and wind pressure distribution of different membrane structures are studied. Based on the results, the wind pressure zones of the roofs are discussed. Furthermore, the original structures are optimized and numerically simulated considering the streamlined design concept to study the influence mechanism of fluctuating wind on the roof in more detail.