Proton‐conducting materials play a key role in various fields, and their proton conduction is profoundly restricted by the proton dissociation process. This process has two components: dissociation from acidic groups (e.g., −SO 3 H) and dissociation from intermediate species (e.g., H 3 O + , C─F···H + ). Extensive research has concentrated on the former, utilizing acidic groups with minimal proton dissociation energy or low pKa values, while the latter's substantial effects have been largely overlooked. In reality, proton‐accepting atoms within intermediates, such as oxygen and nitrogen, typically produce a higher electron cloud density compared to those in acidic groups. This results in a pronounced electrostatic binding effect on mobile protons, as well as high dissociation energies. Thus, diminishing the dissociation energy associated with intermediates is paramount in the development of high‐performance proton conductors. Herein, we construct one covalent organic framework‐based proton conductor, achieving superprotonic conduction over a wide humidity range by decreasing the dissociation energy of protons from intermediates. The success of this approach can be attributed to two key factors: the crowded guest molecules within the framework that mitigate proton hydration, and the concurrent establishment of C─H···H + interactions. These combined effects significantly reduce the electrostatic attraction exerted on mobile protons, thereby enhancing proton conduction.

Solid-state nuclear magnetic resonance (NMR) methods can probe the motions of membrane proteins in liposomes at the atomic level, and propel the understanding of biomolecular processes for which static structures cannot provide a satisfactory description. High-resolution crystallography snapshots have provided a structural basis for fluoride channels. NMR is a powerful tool to build upon these snapshots and depict a dynamic picture of fluoride channels in native-like lipid bilayers. In this contribution, we discuss solid-state and solution NMR experiments to detect fluoride binding and transport by fluoride channels. Ongoing developments in membrane protein sample preparation and ssNMR methodology, particularly in using 1H, 19F and 13C-detection schemes, offer additional opportunities to study structure and functional aspects of fluoride channels.

Carbon structures with covalent bonds connecting C 60 molecules have been reported 1 – 3 , but their production methods typically result in very small amounts of sample, which restrict the detailed characterization and exploration necessary for potential applications. We report the gram-scale preparation of a new type of carbon, long-range ordered porous carbon (LOPC), from C 60 powder catalysed by α-Li 3 N at ambient pressure. LOPC consists of connected broken C 60 cages that maintain long-range periodicity, and has been characterized by X-ray diffraction, Raman spectroscopy, magic-angle spinning solid-state nuclear magnetic resonance spectroscopy, aberration-corrected transmission electron microscopy and neutron scattering. Numerical simulations based on a neural network show that LOPC is a metastable structure produced during the transformation from fullerene-type to graphene-type carbons. At a lower temperature, shorter annealing time or by using less α-Li 3 N, a well-known polymerized C 60 crystal forms owing to the electron transfer from α-Li 3 N to C 60 . The carbon K-edge near-edge X-ray absorption fine structure shows a higher degree of delocalization of electrons in LOPC than in C 60 (s). The electrical conductivity is 1.17 × 10 −2 S cm −1 at room temperature, and conduction at T < 30 K appears to result from a combination of metallic-like transport over short distances punctuated by carrier hopping. The preparation of LOPC enables the discovery of other crystalline carbons starting from C 60 (s).

Perovskite light-emitting diodes (LEDs) have attracted broad attention due to their rapidly increasing external quantum efficiencies (EQEs)(1-15). However, most high EQEs of perovskite LEDs are reported at low current densities (< 1 mA cm(-2)) and low brightness. Decrease in efficiency and rapid degradation at high brightness inhibit their practical applications. Here, we demonstrate perovskite LEDs with exceptional performance at high brightness, achieved by the introduction of a multifunctional molecule that simultaneously removes non-radiative regions in the perovskite films and suppresses luminescence quenching of perovskites at the interface with charge-transport layers. The resulting LEDs emit near-infrared light at 800 nm, show a peak EQE of 23.8% at 33 mA cm(-2) and retain EQEs more than 10% at high current densities of up to 1,000 mA cm(-2). In pulsed operation, they retain EQE of 16% at an ultrahigh current density of 4,000 mA cm(-2), along with a high radiance of more than 3,200 W s(-1) m(-2). Notably, an operational half-lifetime of 32 h at an initial radiance of 107 W s(-1) m(-2) has been achieved, representing the best stability for perovskite LEDs having EQEs exceeding 20% at high brightness levels. The demonstration of efficient and stable perovskite LEDs at high brightness is an important step towards commercialization and opens up new opportunities beyond conventional LED technologies, such as perovskite electrically pumped lasers.

We described an insect-inspired strategy for conferring reversible, high responsivity on polymer microgels to dilute-source CO2 (≤5000 ppm in gas mixtures). This is demonstrated on oligo(ethylene oxide)-based microgels that contain tertiary amines on the polymer chains with proper organic small molecular carbonates in the polymer-solvent system. Similar to the synergistic contribution of the CO2 receptor subunits in mosquitoes for CO2 response, laser light scattering and related studies indicated that the CO2-response of the microgels in terms of the volume changes works through the coordination of different functional moieties in the system, making it different from the conventional CO2-response mechanism. While this pushes the lower response threshold of CO2 concentration down to ca. 1000 ppm, this unique strategy can also satisfy the urge to achieve both effective CO2 capture and facile CO2 release, making it possible to couple the detection with the capture and utilization of indoor excess CO2.

Aqueous Zn‐ion hybrid capacitors (ZIHCs) present prominent potentials in flexible wearable electronics application scenarios due to their inherent high safety and low cost. Simultaneously, volumetric energy density is one of the crucial parameters to determine the lifespan of the wearable electronics, in which lightweight and miniaturization is a cardinal prerequisite for realistic application. In this work, an aqueous ZIHC is constructed by harmonizing interlayer spacing of the laminate graphene film and Zn‐ion solvation structure to improve the electrode space utilization. Laminate graphene film interspacing has been customized in the range of 0.72–0.81 nm via regulating the ratio of crumple graphene mediator, thereby optimizing the transport kinetics of large size hydrated Zn ions. Zn‐ion solvation structure is further tailored by introducing ZnCl 2 electrolyte salt to accouple such regulated laminar ionic transport channel. In a result, the thus‐derived ZIHC demonstrates an ultralong cycling lifespan of 100 000 cycles (93.9% capacitance retention), a preeminent volumetric capacitance (235.4 F cm −3 ), and a remarkable specific area capacitance contribution ( C ssa ≈ 72 µF cm −2 ). Quasi‐solid‐state ZIHC is assembled with ZnCl 2 solution‐filled polyacrylamide gel electrolyte to concurrently achieve a superior areal capacitance of 1227 mF cm −2 and great mechanical flexibility toward practical wearable application.

The copolymerization of acrylonitrile (AN) with a hydrophilic monomer is an effective way to prepare hydrophilic polyacrylonitrile (PAN)-based functional materials. In this study, γ-ray radiation-induced copolymerization of AN and 4-vinylpyridine (4-VP) in dimethylsulfoxide (DMSO) was carried out. The chemical structure, molecular weight, thermal properties, and hydrophilicity of the synthesized copolymers were characterized. The γ-ray radiation could initiate the copolymerization of AN and 4-VP in DMSO at room temperature (0~35 ℃). The monomer conversion reached above 90% at the absorbed dose of 25 kGy, but the molecular weight of the copolymer depended on the dose rate. When the absorbed dose was 30 kGy, a P(AN-co-4-VP) random copolymer solution with a viscosity of 250 Pa⸱s was obtained directly after the monomer solution was irradiated by γ-rays at a lower dose rate of 11 Gy/min. The P(AN-co-4-VP) copolymer had a weight-average molecular weight of 1.34×105, and the relative content of AN and 4-VP units in the copolymer chains was identical to the feed ratio of AN and the 4-VP comonomer. When the dose rate exceeded 20 Gy/min, molecular weight of the synthesized copolymer decreased remarkably. Thermal properties of the P(AN-co-4-VP) random copolymer with the relative molar ratio of 4-VP to AN of 2% were generally the same as those of the PAN homopolymer. The 4-VP units in the polymer chains did not participate in the ring formation or crosslinking reaction of the side ‒C≡N groups. However, the water contact angle of the P(AN-co-4-VP) random copolymer decreased gradually with increase in 4-VP content, indicating that the introduction of 4-VP units can improve the hydrophilicity of the copolymers. This study provides a new idea for the hydrophilic modification of PAN as well as proves that DMSO solutions with a high mass fraction (>20%) of the homo- or copolymer of AN can be obtained directly via radiation-induced solution polymerization, thus expanding the potential applications of the high-energy radiation technique in the field of solution polymerization of AN.

As structural variants of famous hexagonal tungsten bronzes, hexagonal tungsten oxides (HTO) represent an important family with fascinating functional properties, such as piezoelectric, ferroelectric, pyroelectric, and nonlinear optical (NLO) properties. However, none of them are transparent in the deep-UV spectral region, which limits their applications. Herein, we report the first HTO-type monofluorophosphate K3Sc3(PO4)(PO3F)2F5 (I) with deep-UV transparency. Such a monofluorophosphate is NLO-active with a phase-matchable powder second harmonic generation efficiency of 0.9 times that of KH2PO4 at 1064 nm. Importantly, the UV-Vis reflectance spectrum indicates that it is deep-UV transparent down to 200 nm. This work pushes the transparent window of NLO materials with HTO-type structures down to the deep-UV spectral region for the first time and opens up a new door for HTO materials.

This study presented the detailed investigation of the chemical fraction and mobility changes of the colla-gen structure to assess the deterioration of the archeological leather dated from BC210 to BC1046 by the solid-state NMR spectroscopy. The 13 C CP/MAS and DP/MAS NMR spectra of the unaged and artificially aged leather were compared to check the reliability of the 13 C CP/MAS NMR measurement. The consis-tency of above two methodologies suggested the highly efficient 13 C CP/MAS NMR could be employed to quantify the deterioration of the archeological leather, especially the relative fractions of Glycine (Gly), Hydroxyproline (Hyp) and Proline (Pro) with well resolved 13 C resonance lines. Furthermore, the 13 C T 1 measurement determined by Torchia method was adopted to analyze the molecular dynamics changes of the collagen as visualized by the Inverse Laplace Transformation (ILT) of 13 C T 1 relaxation decay curves. The segmental dynamics changes of the representative nuclei acids indicated the different hierarchical structure of different archeological leather samples. The results suggested that tannins and collagen were degraded in the archeological leather buried for thousands of years. The relative fraction and the 13 C T 1 distribution of the particular amino acids residues could be used as the important indicators to assess the collagen degradation. The current study would allow us to further understand the deterioration in the archeological leather through the chemical structure and molecular dynamics changes of the collagen in leather. (c) 2022 Consiglio Nazionale delle Ricerche (CNR). Published by Elsevier Masson SAS. All rights reserved.

Here, we report a finding on light-mediated CO2-responsiveness. It is found on the microgels that are made of side-chain type metallopolymers containing metalla-aromatics. Turbidity and laser light scattering studies on dilute aqueous dispersion of these microgels in dark indicate high CO2-responsivity, but poor reversibility upon N2 purge, which can be improved by exposing to light. This light-mediated CO2-responsiveness can be elucidated by the loss of aromaticity from initial photoexcitation and concurrent formation of a less reactive, antiaromatic excited state of relatively low CO2 binding affinity, and by subsequent relief of antiaromaticity that can enhance the CO2 removal. The finding is also checked by CO2 uptake-release experiments on the microgels, which enables both CO2 capture of high capacity and CO2 removal of good reversibility under a mild condition, allowing effective and reversible response to dilute CO2.

An in situ stretching instrument combined with low field nuclear magnetic resonance (LF-NMR) was designed and developed, namely, Rheo-Spin NMR. The time resolved stress-strain curve together with the corresponding NMR signal can be simultaneously obtained. The Rheo-Spin NMR contains the functional modules, including (1) the in situ stretching module, (2) the NMR signal acquisition module, and (3) the cavity of the NMR positioning module. The unique ring-like shape of the sample is used to replace the traditional dumbbell sample due to limited space in the NMR probe, and the whole ring-like sample will be deformed during the uniaxial stretching process, which avoids the generation of interference signals from the undeformed sample. The designed stretching assembly made by zirconia ceramics is manufactured to match and stretch the ring-like samples. The strain rate can be tuned within the range of 10-5-10-2 s-1 with the maximum stretching ratio λmax of ∼3.8. The in situ stretching experiments combined with LF-NMR were carried out successfully with natural rubber of different fractions of carbon black. The time-resolved T2 relaxometry was adopted to evaluate segmental relaxation during uniaxial deformation which, for the first time, provides the direct and in situ molecular dynamics information. The Rheo-Spin NMR is promising to provide more in-depth insights into the structure and dynamics evolution of polymer products under real service conditions.

Excellent radiation resistance is a prerequisite for pressure-sensitive hydrogels to be used in high-energy radiation environments. In this work, tannic acid-modified boron nitride nanosheet (BNNS-TA) is first prepared as the radiation-resistant additive by a facile one-step ball milling of hexagonal boron nitride and tannic acid. Then, polyacrylamide (PAAm)-based pressure-sensitive hydrogel doped with BNNS-TA and Fe3+ ions is fabricated. The ternary BNNS-TA/Fe3+/PAAm hydrogel exhibits excellent compressive strength (at least four times the compressive strength of unfilled pure PAAm hydrogel), pressure-sensitive performance (gauge factor is up to 1.4), and performance recovery due to the combination of multiple intermolecular interactions, such as covalent crosslinking, hydrogen bonds, and ion coordination interactions. The BNNS-TA/Fe3+/PAAm hydrogel can be made as a pressure sensor installed in the control circuit or attached on the human body to detect human activities accurately. More importantly, the compressive strength and the pressure-sensitive performance of the BNNS-TA/Fe3+/PAAm hydrogel can be maintained after the hydrogel is irradiated by 60Co gamma-ray at an absorbed dose of 15 kGy. As a comparison, the compressive strength of the unfilled PAAm hydrogel is only a quarter of that before irradiation. This work not only reveals a facile method to achieve the preparation of chemically modified BNNS as a promising radiation-resistant additive but also provides a novel strategy for the development of pressure-sensitive hydrogel devices in radiation environments.

The practical application of raw biomass in high-performance supercapacitors is mainly hindered by virtue of their relatively rare efficient storage sites and low diffusion kinetics. Herein, hierarchical porous carbons (HPCs) are synthesized from heavy fraction of bio-oil (HB) based on a hard-template method accompanied by different NaOH activation temperatures. Thanks to the favorable 3D-interconnected hierarchical porous structure, ultrahigh specific surface area (3095 m(2) g(-1)), large total pore volume (1.66 cm(3) g(-1)), as well as reasonable content of oxygen atoms (7.83 at. %), CSB-800 delivers a prominent gravimetric specific capacitance of 351 F g(-1) (0.5 A g(-1)), which is considerably superior or at least comparable than previously reported for other biomass-based materials. In addition, the assembled CSB-800//CSB-800 symmetric supercapacitors can reach a superior energy density of 20 W h kg(-1) at a power density of 350 W kg(-1) (0.5 A g(-1)). The route proposed for preparing HB-based HPCs broadens a new horizon in exploring large-scale synthesis of electrode materials from industrial by-product and kitchen waste. (C) 2020 Elsevier Ltd. All rights reserved.

Heteroatoms in the carbon matrix are generally considered as active sites to enhance potassium storage capacity, while their adverse effects on ion batteries remain unclear. Herein, a series of sulfur doped carbon (SCDP x ) with adjustable S content and crystallinity are accurately synthesized in the closed autoclave by controlling the ratios of precursors. Electrochemical measurements exhibit that heteroatom sulfur displays double‐edged electrochemical activities with a high initial potassium storage capacity but poor cycling stability for carbon anode. Combined with solid‐state nuclear magnetic resonance (NMR), catalytic tests, and various ex‐situ characterizations, it is demonstrated that abundant S in the carbon would not only form CSC bonds, acting as active sites to reversibly adsorb/desorb potassium ions for high capacity, but also significantly catalyze the reduction and decomposition of the electrolyte including KPF 6 and ethylene carbonate/diethyl carbonate (EC/DEC) to form thicker solid electrolyte interface (SEI) and degrade electrolyte, resulting in rapid capacity decay. As a result, the optimized sample (SCDP2) with the appropriate sulfur doping content exhibits the best electrochemical performance with high capacity (688.4 mA h g −1 at 100 mA g −1 ), long‐term cycling stability (198.4 mA h g −1 at 2000 mA g −1 after 10 000 cycles), and excellent rate capability (238.8 mA h g −1 at 5000 mA g −1 ).

The chain dynamics and crystalline network structure of poly[R-3-hydroxybutyrate-co-4-hydroxybutyrate] (P(3HB-co-4HB)) were systematically investigated by the combination of various solid-state NMR techniques. High-resolution 13C cross-polarization (CP) and direct-polarization (DP) MAS with selective recycle delay times were first used to check the presence or absence of the 4HB unit in the crystalline domain. The results show that the 4HB unit is excluded from the crystalline domain. Afterward, 1H MAS Nuclear Overhauser Effect Spectroscopy (NOESY) with different mixing times was used, which shows that no micro-phase separation exists in the amorphous domain. 1H magic-sandwich-echo (MSE)-FID at elevated temperature shows the absence of motions on a timescale of 100 μs and below in the crystalline domain, as evidenced by the invariant second moment M2 of the proton line shape. Finally, the crystalline based network density was characterized directly by magic and polarization echo (MAPE)-double quantum (DQ) NMR, which shows a significant decreasing tendency after 80 °C. Such a decreasing crystalline network density, together with the reduced relaxation time, results in the significant decrement of the maximum stretch ratio and modulus in the high-temperature region.

Here, we report a distinct approach for regulating the substrate specificity of enzymes immobilized in microgels by a phase transition in polymer networks. The finding is demonstrated on glucose oxidase that is immobilized in thermoresponsive poly(N-isopropylacrylamide)-based microgels. Laser light scattering and enzymatic oxidation tests indicate that the broadened specificity appears at low temperatures, at which the gel matrix is in the relatively swollen state relative to its state at microgel synthesis temperature; upon heating to the relative higher temperatures, the gel matrix is not able to shrink further that offers a tight space in which the enzyme resides to retain high glucose specificity. It is proposed that polymer phase transition in the gel matrix mainly alter protein gates that control passage of substrates into active sites, making them open or close to a certain extent that enable reversible regulating the substrate specificity. The finding is also observed on bulk gels under a rational design, making it of potential interest in enzymatic biofuel cell applications.

Pyrazolylimine-based nickel catalysts bearing intramolecular π–π and H-bonding interactions show high activity, thermal stability, and Mn of polyethylene.

The effects of heating rate on the evolution of tar obtained from heavy fraction of bio-oil (HB) were revealed by the change of elements, functional groups and chemical compounds. The results showed that slow heating rate had a negligible effect on the physicochemical properties of HB from 400 to 800 degrees C. By contrast, decomposition, radical recombination and polymerization reactions could occur at fast heating rate. A clear trend of increasing tar yields was monitored from 300 - 500 degrees C. However, a significant decrease was observed at high temperature (600 - 800 degrees C). Through elemental analyzer, C content in tar expanded with the temperature increasing, whereas N content remained unchanged. Nuclear magnetic resonance (NMR) spectroscopy results indicated that the carboxyl functional groups would be destroyed at high temperature. Furthermore, the concentrations of aromatics showed a trend to increase accompanied by a simultaneous decrease in phenols with the temperature rising according to gas chromatography/mass spectrometer (GC/MS) analysis.

The catalysis of boronic acids immobilized in polymer microgels can be modulated by bubbling with N2/CO2 gas, and in some cases by adding glucose, making their catalytic activity comparable or even superior to that of the corresponding free boronic acid monomers homogeneously dispersed in solutions and, more importantly, making these boronic-acid-containing polymer microgels able to catalyze alternate reactions that may extend the usefulness. This enhanced catalytic function of these boronic-acid-containing microgels as organoboron acid catalysts is plausibly achieved via in situ reversibly structural variations. Kinetic studies have been carried out on the model boronic-acid-catalyzed aza-Michael addition, aldol, amidation, and [4 + 2] cycloaddition reactions in order to better understand the catalytic process.

The copolymerization of ethylene and different α-olefins could result in polyethylene (PE) with different structural topologies, and lead to polyethylene products with different macroscopic performances. Herein, three different polyethylene samples, namely low-density polyethylene (l-PE), metallocene catalyzed ethylene-hexene copolymer (h-PE) and ethylene-octene copolymer (o-PE), were selected as representatives to construct the structure-process-property relationship during film blowing. The detailed crystal-based network evolution during film blowing was first characterized by in-situ synchrotron radiation X-ray scattering. The crystallization process of l-PE film is determined by the coupling effects of temperature and flow, while those of h-PE and o-PE films are dominated by the temperature. Furthermore, the hierarchical crystal structure from the molecular scale to micrometers of final films and segmental dynamics were systematically characterized by multiple ex-situ characterization techniques, i.e. Solid-State NMR, FTIR, SEM. l-PE film shows the crystalline morphology of the row-nucleated structure, whereas h-PE and o-PE show spherulite-like superstructure with better mechanical properties. The current study tentatively constructs the relation of primary chemical structure, microstructural evolution and macroscopic performances of different polyethylene copolymers during film blowing.