Comb‐shaped guanidinium functionalized poly(ether sulfone)s for anion exchange membranes: Effects of the spacer types and lengths

A series of poly(ether sulfone)‐based anion exchange membranes (AEMs), tethering with guanidinium side chains with different spacers, were synthesized via azide‐alkyne cycloaddition, deprotection, and the subsequent ion exchange reactions. The designed polymer structures were verified by the ¹H NMR spectra. Because of the appropriate water uptake and formation of interconnected ionic clusters, the GPES‐3C with propyl spacer showed higher conductivity than the GPES‐1C and GPES‐9C, with methylene and nonyl spacers, respectively. Comparatively, the GPES‐EO AEM with two ethylene oxide (EO) spacers exhibited even higher conductivity, these can be interpreted by interconnectivity of ionic channels and hydrophilicity nature of the EO spacer. Additionally, although the GPES membranes displayed sufficient thermal stability, the chemical stability of as‐prepared materials needs to be much improved for fuel cell applications. Overall, these results demonstrated that the properties of “pendent‐type” AEM can be tuned facilely by the spacer types and lengths. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1313–1321     

A Simple Proof of Dieudonn-Manin Classification Theorem

The Dieudonn-Manin classification theorem on φ-modules (φ-isocrystals) over a perfect field plays a very important role in p-adic Hodge theory. In this note, in a more general setting we give a new proof of this result, and in the course of the proof, we also give an explicit construction of the Harder-Narasimhan filtration of a φ-module.     

Immobilization of AIEgens into metal‐organic frameworks: Ligand design,emission behavior,and applications

Aggregation‐induced emission (AIE), in which the luminophores are highly emissive in aggregate state, is one of the most unique photophysical phenomena and has shown interesting applications in many areas. The immobilization of AIE luminogens (AIEgens) into metal‐organic frameworks (MOFs), which are inorganic‐organic hybrid porous materials with tunable and predictable structures, has been investigated over the past few years. These well‐defined porous frameworks cannot only provide an ideal platform for studying the mechanism of AIE phenomenon in solid state, but also show potential applications from sensing to white light‐emitting diodes. In this highlight, we will summarize the recent progress of AIEgens‐based MOFs, including ligand design, emission behavior, and applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1809–1817     

Conducting polymer engineered covalent organic framework as a novel electrochemical amplifier for ultrasensitive detection of acetaminophen

Two-dimensional covalent organic framework(COF) has distinctive properties that offer potential opportunities for developing advanced electrode materials.In this work,a core-shell material composed of TAPB-DMTP-COF(TAPB,1,3,5-tris(4-aminophenyl)benzene;DMTP,2,5-dimethoxyterephaldehyde)core and conducting polymer shell,TAPB-DMTP-COF@PANI,was synthesized solvothermally using a polymerization method.The structural cha racteristics of the prepared composite were revealed by X-ray diffraction patterns(XRD),fourier transform infrared spectra(FTIR),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM).The electrochemical analyses were verified by subsequent monitoring of trace levels of acetaminophen.This resultant composite not only facilitated acetaminophen to interact with absorption sites by π-π stacking effect and hydrogen bonding but also overcame the poor conductivity of COF.Under the optimal conditions,a low limit of detection of0.032 μmol/L and wide linear range of 0.10-500 μmol/L were obtained.The electrochemical platform was almost unaffected by other interfering substances,and successfully applied for the practical detection of acetaminophen in commercial tablet,human blood serum and urine.The enhanced performance makes this COF based core-shell composite a promising material in electrochemical senso r.     

Self-Assembly Approach Towards MoS2-Embedded Hierarchical Porous Carbons for Enhanced Electrocatalytic Hydrogen Evolution

Transition metal-based nanoparticle-embedded carbon materials have received increasing attention for constructing next-generation electrochemical catalysts for energy storage and conversion. However, designing hybrid carbon materials with controllable hierarchical micro/mesoporous structures, excellent dispersion of metal nanoparticles, and multiple heteroatom-doping remains challenging. Here, a novel pyridinium-containing ionic hypercrosslinked micellar frameworks (IHMFs) prepared from the core–shell unimicelle of s-poly(tert-butyl acrylate)-b-poly(4-bromomethyl) styrene (s-PtBA-b-PBMS) and linear poly(4-vinylpyridine) were used as self-sacrificial templates for confined growth of molybdenum disulfide (MoS₂) inside cationic IHMFs through electrostatic interaction. After pyrolysis, MoS₂-anchored nitrogen-doped porous carbons possessing tunable hierarchical micro/mesoporous structures and favorable distributions of MoS₂ nanoparticles exhibited excellent electrocatalytic activity for hydrogen evolution reaction as well as small Tafel slope of 66.7 mV dec⁻¹, low onset potential, and excellent cycling stability under acidic condition. Crucially, hierarchical micro/mesoporous structure and high surface area could boost their catalytic hydrogen evolution performance. This approach provides a novel route for preparation of micro/mesoporous hybrid carbon materials with confined transition metal nanoparticles for electrochemical energy conversion.     

A cinnamoyl substituted Nile Red-based probe to detect hydrazine

Herein we discovered that a Nile Red-based probe with a cinnamoyl unit was highly selective and sensitive to N₂H₄. Hydrazinolysis by N₂H₄ would release a hydroxyl substituted Nile Red and result in remarkable fluorescence quench. Importantly, Cys/Hcy would not interrupt the N₂H₄ recognition. This is because, for this probe, the combination of the π-π conjugate system can stabilize the ethylene union, which results in the nucleophilic addition of the thiol group of Cys/Hcy becomes non-effective.     

Click chemistry for the synthesis of 5-substituted 1H-tetrazoles from boron-azides and nitriles

A novel and metal free catalysis of synthesizing 5-substituted 1H-tetrazoles through 1,3-dipolar cycloaddition of boron-azides and nitriles is reported with broad substrate scope and excellent yields.     

Solution‐processable transmissive‐to‐green switching electrochromic polyamides bearing 2,7‐bis(diphenylamino)naphthalene units

A new 2,7‐bis(diphenylamino)naphthalene‐based diamine monomer, N,N′‐bis(4‐aminophenyl)‐N,N′‐bis(4‐methoxyphenyl)‐2,7‐naphthalenediamine, was synthesized and polymerized with various aromatic dicarboxylic acids via the phosphorylation polyamidation reaction leading to a new series of redox‐active and electrochromic aromatic polyamides. The polyamides exhibited high solubility in many polar aprotic solvents, good film‐forming ability, and high thermal stability. They also showed stable electrochemical stability and anodically green coloring when oxidized. The two arylamino centers showed a weak electronic interaction via the 2,7‐naphthalenediyl bridge, and thus they started to oxidize almost at the same time. No intervalence charge transfer (IVCT) absorption was observed during the oxidation processes of these polyamides. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1409–1421     

Analytic approximation of the blow‐up time for nonlinear differential equations by the ADM–Padé technique

We present a new approach to calculate analytic approximations of blow‐up solutions and their critical blow‐up times. Our approach applies the Adomian decomposition–Padé method to quickly and easily compute the critical blow‐up times, which comprises the Adomian decomposition method combined with the Padé approximants technique. We validate our new approach with a variety of numerical examples, including nonlinear ODEs, systems of nonlinear ODEs, and nonlinear PDEs. Furthermore, our new method is shown to be more convenient than prior art that relies on compound discretized algorithms. Copyright © 2013 John Wiley & Sons, Ltd.     

Novel voltage signal at proximity-induced superconducting transition temperature in gold nanowires

We observed a novel voltage peak in the proximity-induced superconducting gold (Au) nanowire while cooling the sample through the superconducting transition temperature. The voltage peak turned dip during warming. The voltage peak or dip was found to originate respectively from the emergence or vanishing of the proximity-induced superconductivity in the Au nanowire. The amplitude of the voltage signal depends on the temperature scanning rate, and it cannot be detected when the temperature is changed slower than 0.03 K/min. This transient feature suggests the non-equilibrium property of the effect. Ginzburg-Landau model clarified the voltage peak by considering the emergence of Cooper pairs of relatively lower free energy in superconducting W contact and the non-equilibrium diffusion of Cooper pairs and quasiparticles.