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Hydrogels that combine electrical conductivity, mechanical and self‐adhesion properties have attracted considerable interest because of their promising applications in wearable devices and flexible supercapacitors, among others. However, the weak interfacial adhesion between adjacent layers of flexible supercapacitors limits their practical applications. In this work, mussel‐inspired nanocomposite hydrogels composed of tannic acid (TA)‐modified doped polyaniline (PANI) and functional monomer acrylamide (AAm) were prepared, the hydrogel exhibited good mechanical properties (903 % strain at break) and adhesion properties. In a three‐electrode system the hydrogel exhibited a specific capacitance of 851.1 mF cm−2 (at 1 mA cm−2) and good stability. All‐hydrogel supercapacitors with robust interfacial capabilities were assembled on this basis without additional immobilization. The flexible supercapacitors show favorable electrochemical performance (570 mF cm−3 at 1 mA cm−2) and provide a volume energy density 55.9 μWh cm−3 and a capacitance retention of 85.6 % after 2000 cycles. Compared with previous conductive hydrogels, this work will provide a new approach to fabricate nanocomposite hydrogels with self‐adhesive, robust mechanical properties and conductive performance, effectively improving the interfacial adhesion of integrated supercapacitors and expanding the application scope of flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Purpose: Optimizing three‐dimensional (3D) k‐space sampling trajectories is important for efficient MRI yet presents a challenging computational problem. This work proposes a generalized framework for optimizing 3D non‐Cartesian sampling patterns via data‐driven optimization. Methods: We built a differentiable simulation model to enable gradient‐based methods for sampling trajectory optimization. The algorithm can simultaneously optimize multiple properties of sampling patterns, including image quality, hardware constraints (maximum slew rate and gradient strength), reduced peripheral nerve stimulation (PNS), and parameter‐weighted contrast. The proposed method can either optimize the gradient waveform (spline‐based freeform optimization) or optimize properties of given sampling trajectories (such as the rotation angle of radial trajectories). Notably, the method can optimize sampling trajectories synergistically with either model‐based or learning‐based reconstruction methods. We proposed several strategies to alleviate the severe nonconvexity and huge computation demand posed by the large scale. The corresponding code is available as an open‐source toolbox. Results: We applied the optimized trajectory to multiple applications including structural and functional imaging. In the simulation studies, the image quality of a 3D kooshball trajectory was improved from 0.29 to 0.22 (NRMSE) with Stochastic optimization framework for 3D NOn‐Cartesian samPling trajectorY (SNOPY) optimization. In the prospective studies, by optimizing the rotation angles of a stack‐of‐stars (SOS) trajectory, SNOPY reduced the NRMSE of reconstructed images from 1.19 to 0.97 compared to the best empirical method (RSOS‐GR). Optimizing the gradient waveform of a rotational EPI trajectory improved participants' rating of the PNS from "strong" to "mild." Conclusion: SNOPY provides an efficient data‐driven and optimization‐based method to tailor non‐Cartesian sampling trajectories. [ABSTRACT FROM AUTHOR]

Flexible electronics have achieved development with the rising consumption of wearable devices. In this work, a novel polyacrylamide‐graphene oxide‐polyaniline composite hydrogel (PGPH) based flexible electrode with good mechanical and electrochemical properties is prepared. The polyacrylamide interpenetrating network can provide a porous substrate. The strong π–π interaction between graphene oxide and polyaniline can stabilize polyaniline. The area‐specific capacitance of PGPH is 100.57 mF cm–2 at a current density of 5 mA cm–2, and the capacity remains at 75.54% after 1000 cycles. One layer of sodium alginate is spin‐coated on top of the electrode to solve the problem of desorption of conductive materials and improve the cycle stability of the materials. The PGPH exhibits a conductivity of 5.11 S m–1 and elongation at break of 352%, which is significantly higher than that of common polyacrylamide‐polyaniline hydrogel. Based on the good mechanical and electrochemical properties of PGPH, it has broad application prospects in flexible energy storage devices and flexible sensors. [ABSTRACT FROM AUTHOR]

The development of high‐temperature proton exchange membrane fuel cells calls for better membrane, and a polyacrylamide/β‐cyclodextrin hydrogel proton exchange membrane is prepared by solution polymerization of β‐cyclodextrin (β‐CD) and acrylamide (Am), for which ammonium persulfate (APS) and N, N″‐(methylene)bisacrylamide (MBA) is used as initiator and crosslinking agent, respectively. The observed proton conductivity of the membrane reaches 12.3 S m−1 at room temperature, when the ratio of β‐CD, APS, MBA to Am monomer is 0.42 mol%, 0.37 mol%, and 0.14 mol%, respectively, and the primary concentration of doped phosphoric acid is 8 mol L−1. The observed proton conductivity evolution on temperature obeys Arrhenius' law, indicating that the proton conduction mainly follows the hopping mechanism. In addition, the prepared PAM/β‐CD proton exchange membrane has a mass loss of only 8.47% at 205 °C, showing good thermal stability compared with PBI membrane. It also has good antioxidative stability as well as promising potential application in high‐temperature fuel cells. [ABSTRACT FROM AUTHOR]

A kinetic Monte Carlo model of polyurethane polymerization which explicitly tracks the polymer sequences is developed and shared. This model is benchmarked against theoretical and experimental polyurethane data and used to investigate the effect on oligomer distributions of unequal reactivity of the first and second isocyanate to react. The reverse reactions using thermodynamic consistency are then added to the framework, and analogous to the addition polymerization concept of ceiling temperature, equilibrium chain length distributions at various temperatures are calculated. For a mixture of three monomers AA, BB, and CC, where BB and CC do not react with one another, are present in stoichiometric proportions, and have different enthalpies of reaction with AA, an odd‐even effect emerges. Odd length chains are more likely than even length chains for temperatures at which BB and CC have significantly different equilibrium conversions. The concept of ceiling temperature that is typically cited for addition polymers is extended here to provide a measure of conditions under which depolymerization for recycling is favored. [ABSTRACT FROM AUTHOR]

A series of Dy3+/Eu3+ single‐ and co‐doped calcium borosilicate luminescent glasses were prepared by the conventional high temperature melt‐quenching method. A compact glass structure is obtained by the addition of Dy3+/Eu3+ ions, which is verified by the physical properties of synthetic glasses. As network modifiers, Dy3+/Eu3+ fill in the interspaces of glass network and contribute to the conversion of [BO3] to [BO4]. Dy3+/Eu3+ co‐doped calcium borosilicate glasses can emit white light, which consists of blue, yellow, and red light under 387 nm excitation. The emission spectra and decay curves of the white‐emitting glasses have proved the existence of energy transfer. The average lifetime of Dy3+ decreases from 0.251 to 0.165 ms with the increasing Eu3+ concentration. Changing rare earth ions concentration, CIE color coordinates of Dy3+/Eu3+ co‐doped glass shifts from cyan to white with increasing excitation wavelength. A white‐light emission is obtained when the concentration of Dy3+ and Eu3+ equals to 4% and 2%, respectively. Moreover, the Dy3+/Eu3+ co‐doped calcium borosilicate glass shows high‐thermal stability and it may be applicable for high‐quality white LEDs based on high power near ultraviolet (n‐UV) LED chip in the future. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: With the emergence of lignocellulose refining, there is an increasing interest in exploring the valuable applications for lignin due to its abundant and underused features. Originating from the physiological function of lignin in plants, this work attempted to evaluate the antimicrobial potential of enzymatic hydrolysis lignin (EHL) from a bioethanol‐derived biorefinery. RESULTS: Successive ethanol–water dissolution was employed to fractionate EHL and the antimicrobial activities of three obtained lignin fractions (F1, F2 and F3) were compared by the agar diffusion method and minimum inhibitory concentration (MIC) assays. Interestingly, the results showed that the antimicrobial activities of EHL were centralized in F1 which exhibited obviously growth inhibitory effects against two Gram‐positive (Staphylococcus aureus and Bacillus subtilis) and two Gram‐negative (Escherichia coli and Salmonella enterica) bacteria with MICs of 1, 2, 2 and 2 mg mL−1, respectively. The further characterization suggested that the better solubility and higher phenolic hydroxyl content of F1 caused by lower molecular weight were possibly responsible for the improvement of antimicrobial performance. CONCLUSIONS: Consequently, this work suggested that successive ethanol–water fractionation was an effective way to enhance the antimicrobial activity of EHL. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The red-emitting phosphor Ca0.8Zn0.2TiO3:Pr3+ was synthesized using an ethylene glycol (EG)-assisted hydrothermal method. The effects of additional amounts of and order of adding EG, plus hydrothermal temperature, time, and pH on the composition, morphology and optical properties of the titanate phosphors were studied. The crystalline phases of the titanate phosphors were confirmed to be constituted of a series of co-existing CaTiO3, Zn2TiO4 and Ca2Zn4Ti16O38 compounds in various proportions that were visualized using an X-ray diffractometer (XRD). The optical properties of the phosphors were studied using photoluminescence spectra and UV-visible spectroscopy. The results show that the impurities Zn2TiO4:Pr3+ and Ca2Zn4Ti16O38:Pr3+ significantly contributed to the enhancement of an absorption band around 380 nm. The optimum Ca0.8Zn0.2TiO3:Pr3+ phosphor consisting of appropriate amounts of CaTiO3, Ca2Zn4Ti16O38 and Zn2TiO4 in three phases was achieved by controlling the hydrothermal conditions, and the obtained red phosphor exhibited the highest red emission (1D2 → 3H4 transition of Pr3+) with an ideal chromaticity coordinate located at ( x = 0.667, y = 0.332) under 380 nm excitation. [ABSTRACT FROM AUTHOR]

The cover image, by Guanhua Wang et al., is based on the Research Article Successive ethanol‐water fractionation of enzymatic hydrolysis lignin to concentrate its antimicrobial activity, DOI: 10.1002/jctb.5656. [ABSTRACT FROM AUTHOR]