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The semi-interpenetrating network anion exchange membranes (AEMs) based on quaternized polyvinyl alcohol (QPVA) and poly(diallyldimethylammonium chloride) (PDDA) are synthesized. The chemical cross-linking structure is formed between hydroxyl groups of QPVA and aldehyde groups of glutaraldehyde (GA), which makes PDDA more stable embed in the QPVA matrix and also improves the mechanical properties and dimensional stability of AEMs. Due to the phase separation phenomenon of AEMs swelling in water, a microporous structure may be formed in the membrane, which reduces the transmission resistance of hydroxide ions and provides a larger space for the transfer of hydroxide ions, thus improving the conductivity. The ring structure of PDDA is introduced as a cationic group to transfer hydroxide ions, and shields the nucleophilic attack of the hydroxide ions through the steric hindrance effect, which improves alkaline stability. The hydroxide conductivity of semi-interpenetrating network membrane (QPVA/PDDA0.5-GA) is 36.5 mS cm−1 at 60 °C. And the membrane of QPVA/PDDA0.5-GA exhibits excellent mechanical property with maximum tensile strength of 19.6 MPa. After immersing into hot 3 mol L−1 NaOH solutions at 60 °C for 300 h, the OH− conductivity remains 78% of its initial value. The semi-interpenetrating network AEMs with microporous structure exhibit good ionic conductivity, mechanical strength and alkaline durability.

Self-healing conductive elastomers have been widely used in smart electronic devices, such as wearable sensors. However, nano fillers hinder the flow of polymer segments, which make the development of conductive elastomer with rapid repair and high ductility a challenge. In this work, thioctic acid (TA) was grafted onto amino-modified polysiloxane (PDMS-NH2) by dehydration condensation of amino group and carboxyl group. By introducing gold nanoparticles, a dynamic network based on S-Au interaction was constructed. The dynamic gold cross-linking could effectively dissipate the energy exerted by external force and improve the extensibility of conductive elastomer. In addition, S-Au interaction had a good optothermal effect, so that the elastomer rapidly healed under NIR irradiation, and the repair efficiency reached 92%. We further evaluated the performance of the conductive elastomer as a strain sensor. The sample could accurately monitor the bending of human joints and small muscle state changes. This kind of self-healable conductive elastomer based on dynamic S-Au interaction has great potential in the fields of interpersonal interaction and health monitoring.

Metal-organic frameworks are new kinds of porous crystalline materials. The Zr-based metal-organic framework (MOF-801) is consists of [Zr6(u3-O)4(u3-OH)4]12+ clusters and fumaric acid connectors. MOF-801 has excellent mechanical properties, high chemical stability and high water absorption capacity. There are a large number of hydrophilic functional groups inside MOF-801, which is effective to promote interfacial compatibility between MOF-801 and polymer matrixes. In this work, the MOF-801 with structural defects was synthesized through the solvothermal method by adding excess formic acids as the regulator. These structural defects could confer MOF-801 high surface area (2476.34 m2 g−1) and promote the water absorption capacity. Moreover, structural defects could also expose more open metal sites of MOF-801, thereby increasing the Lewis acidity of MOF-801. Then, the hybrid membranes were synthesized by combining the MOF-801 with structural defects and C-SPAEKS. Dense hydrogen-bond networks formed between the MOF-801 and C-SPAEKS further promote enhance proton conductivity. At the condition of 90 °C and 100% relative humidity, the highest proton conductivity of hybrid membranes reached 0.100 S cm−1, which is similar to that of Nafion 117. Meanwhile, these hybrid membranes showed outstanding chemical and thermal stabilities. These results indicate that these hybrid membranes have potential as proton exchange membranes.

We report a novel comb-shaped anion exchange membrane based on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) and 4-(dimethylamino)butyraldehyde diethyl acetal (DABDA). The Menshutkin reaction successfully introduced DABDA into the brominated PPO backbone, which was proved through FT-IR and 1H NMR. The distinct hydrophilic/hydrophobic microphase separation structure observed by transmission electron microscope (TEM). As the increase of grafting degree, so does the water uptake, swelling ratio, hydroxide conductivity and alkaline stability. The membranes also possess good mechanical property with tensile strength from 14.2 to 38.11 MPa. This is due to the increasing number of hydroxide and unique steric hindrance effect caused the higher water uptake and higher dimensional stability. Simultaneously, especially PPO/DABDA-60 in comb-shaped membranes demonstrate an excellent long-term alkali resistance stability. In a 576-h alkali resistance stability test, the retained ionic conductivity of the PPO/DABDA-60 membrane is 96% of the initial value. The PPO/DABDA-60 is a potential candidate material for AEM.

Flash Joule heating (FJH), an advanced material synthesis technique, has been used for the production of high-quality carbon materials. Direct current discharge through the precursors by large capacitors has successfully converted carbon-based starting materials into bulk quantities of turbostratic graphene by the FJH process. However, the formation of other carbon allotropes, such as nanodiamonds and concentric carbon materials, as well as the covalent functionalization of different carbon allotropes by the FJH process, remains challenging. Here, we report the solvent-free FJH synthesis of three different fluorinated carbon allotropes: fluorinated nanodiamonds, fluorinated turbostratic graphene, and fluorinated concentric carbon. This is done by millisecond flashing of organic fluorine compounds and fluoride precursors. Spectroscopic analysis confirms the modification of the electronic states and the existence of various short-range and long-range orders in the different fluorinated carbon allotropes. The flash-time-dependent relationship is further demonstrated to control the phase evolution and product compositions.

Hybrid nanomaterials with controlled dimensions, intriguing components and ordered structures have attracted significant attention in nanoscience and technology. Herein, we report a facile and green polyoxometallate (POM)-assisted hydrothermal carbonization strategy for synthesis of carbonaceous hybrid nanomaterials with molecularly dispersed POMs and ordered mesopores. By using various polyoxometallates such as ammonium phosphomolybdate, silicotungstic acid, and phosphotungstic acid, our approach can be generalized to synthesize ordered mesoporous hybrid nanostructures with diverse compositions and morphologies (nanosheet-assembled hierarchical architectures, nanospheres, and nanorods). Moreover, the ordered mesoporous nanosheet-assembled hierarchical hybrids with molecularly dispersed POMs exhibit remarkable catalytic activity toward the dehydration of tert-butanol with the high isobutene selectivity (100 %) and long-term catalytic durability (80 h).

As graphene enjoys worldwide research and deployment, the biological impact, geologic degradation, environmental retention, and even some physical phenomena remain less well studied. Bulk production of 13C-graphene yields a powerful route to study all of these questions. Gram-scale synthesis of high-quality and high-purity turbostratic flash graphene with varying amounts of 13C-enrichment, from 5% to 99%, is reported here. The material is characterized by solid state NMR spectroscopy, Raman spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma mass spectrometry. Notably, an unusual enhancement in the Raman spectroscopic D' peak is observed, resulting from the modification in vibrational frequency through isotopic enrichment favoring intravalley phonon scattering modes. While the IR absorbance spectrum of graphene is for the most part silent, we prepare here 13C-enhanced graphene samples that show a large aromatic 12C═13C stretch that reveals this IR-active mode.

Ultra-high frequency (UHF) radio frequency identification (RFID) tags with an antenna made of a highly flexible graphene assembly film (GAF) is presented. The superb electrical conductivity (∼1.6 × 106 S m−1) of the GAF results in the tag to reach reading range of ∼12 m, which is comparable to that of the commercially available metallic counterparts. The performance of the GAF-based RFID tags under mechanical bending and stretching is experimentally evaluated, which demonstrates excellent mechanical stability of the GAF tag than that of metallic tags. Additionally, substrate stability tests are also conducted. The GAF-based UHF RFID tags can thus lead to numerous applications in information exchange, tracking and tracing as well as the Internet of Things (IoT).

Hypothesis Depending on their composition, hydrated gels can be homogeneous or phase-separated, which, in turn, affects their dynamical and mechanical properties. However, the nature of the structural features, if any, that govern the propensity for a given gel to phase-separate remains largely unknown. Here, we argue that the propensity for hydrated gels to phase-separate is topological in nature. Simulations We employ reactive molecular dynamics simulations to model the early-age precipitation of calcium–alumino–silicate–hydrate (C A S H) gels with varying compositions, i.e., (CaO)1.7(Al2O3)x(SiO2)1 – x(H2O)3.7 + x. By adopting topological constraint theory, we investigate the structural origin of phase separation in hydrated gels. Findings We report the existence of a homogeneous-to-phase-separated transition, wherein Si-rich (x ≤ 0.10) C A S H gels are homogeneous, whereas Al-rich (x > 0.10) C A S H gels tend to phase-separate. Furthermore, we demonstrate that this transition is correlated to a topological flexible-to-rigid transition within the atomic network. We reveal that the propensity for topologically-overconstrained gels to phase-separate arises from the existence of some internal stress within their atomic network, which acts as an energy penalty that drives phase separation.

We achieved the total synthesis of the proposed structure of characellide B, a novel lipoglycotripeptide. Comparison of the data for the synthetic compound with those for the natural product indicated some possible errors in the original structural assignment. Furthermore, we synthesized the other four stereoisomers, focusing on the d-Asp-d-allo-Thr fragment, to determine the actual structure of characellide B. Nevertheless, the data for the stereoisomers were not consistent with those for the natural product.

Labeling approaches using isobaric chemical tags (e.g., isobaric tagging for relative and absolute quantification, iTRAQ and tandem mass tag, TMT) have been widely applied for the quantification of peptides and proteins in bottom-up MS. However, until recently, successful applications of these approaches to top-down proteomics have been limited because proteins tend to precipitate and “crash” out of solution during TMT labeling of complex samples making the quantification of such samples difficult. In this study, we report a top-down TMT MS platform for confidently identifying and quantifying low molecular weight intact proteoforms in complex biological samples. To reduce the sample complexity and remove large proteins from complex samples, we developed a filter-SEC technique that combines a molecular weight cutoff filtration step with high-performance size exclusion chromatography (SEC) separation. No protein precipitation was observed in filtered samples under the intact protein-level TMT labeling conditions. The proposed top-down TMT MS platform enables high-throughput analysis of intact proteoforms, allowing for the identification and quantification of hundreds of intact proteoforms from Escherichia coli cell lysates. To our knowledge, this represents the first high-throughput TMT labeling-based, quantitative, top-down MS analysis suitable for complex biological samples.

Reasonable structure and composition are essential for electromagnetic wave absorption (EMW). Herein, ZnO hollow spheres were prepared with carbon spheres as templates and then synthesized ZnO/ZnCo2O4 composites by the solvothermal method and annealing treatment. The flower-like ZnCo2O4 material was produced by self-assembly of ZnCo2O4 nanosheets. The absorbing material with the complex structure has multiple scattering and reflection, conduction loss, resonance, and eddy current loss characteristics. Furthermore, the addition of ZnO hollow spheres has a significant impact on electromagnetic parameters and absorption properties. As a result, the addition of ZnO hollow spheres can greatly enhance the complex permittivity of the ZnO/ZnCo2O4 composites and obtain excellent EMW absorbing properties. It is worth noting that ZnO/ZnCo2O4 composites show the best EMW absorption properties when the ZnO hollow spheres were added up to 5 mg. The minimum reflection loss is −55.42 dB and a matching thickness of 1.99 mm while the maximum effective absorption bandwidth can also reach 7.44 GHz with a matching thickness of 2.4 mm. Our research can prove that the structure and composition have a significant influence on the properties of the absorbing material, which provides ideas for the development of absorbing materials with high-performance.

l-Threonine aldolase (LTA) is an attractive tool in organic chemistry for catalyzing the formation of β-hydroxy-α-amino acids with two chiral centers. The enzyme has a strict selectivity for Cα of ...

Electrochemical oxygen reduction to hydrogen peroxide is now being studied as a promising renewable and localized alternative for the traditional complex anthraquinone process. Catalysts for this t...

A series of quaternary ammonium salt poly(ether ether ketone) AEMs containing long ether substituents are successfully prepared, and their chemical structure is confirmed by 1H NMR and FT-IR. The distinct microphase separation morphology of AEMs is observed by TEM. As the content of methylhydroquinone increases, the ion conductivity of AEMs gradually increases. When the content of methylhydroquinone increases to 80%, the hydroxide conductivity of PEEK-DABDA-80 membrane reaches 0.052 S/cm at 80 °C. Meanwhile, it exhibits excellent mechanical properties and anti-swelling ability, with tensile strength of 25 MPa, elongation at break of 8.12% and swelling ratio is only 17.4% at 80 °C. And AEMs also display the better thermal stability. After soaked in 1 M NaOH at 60 °C for 30 days, PEEK-DABDA-80 membrane shows acceptable ion conductivity of 0.021 S/cm at 60 °C. In view of these properties, PEEK-DABDA-x AEMs may display potential application as alkaline AEMs.

Photothermal therapy (PTT) based on semiconducting polymer nanoparticles (SPNs) is a promising strategy to treat solid tumors, but its ability to combine with chemotherapy for immune remodeling to efficiently suppress metastatic cancers has rarely been studied. Here, we demonstrate that PTT combined with chemotherapy can efficiently elicit immunity to suppress metastatic tumor growth. Specifically, we rationally designed a new SPN (PDPSe NPs) as a photothermal agent for PTT with a large mass extinction coefficient in the near-infrared region (e.g., 44.9 L g-1 cm-1 at 808 nm), high photothermal conversion efficiency (62.5%) and excellent biocompatibility. A hypoxia-activated anti-tumor drug, tirapazamine (TPZ), was selected for chemotherapy. Strikingly, the combination therapy not only induced tumor cell death in the primary tumor, but also effectively suppressed the growth of distant tumors (mimicking metastatic tumors) without PTT. Importantly, the combined therapies exhibit synergistic effects on immune remodeling. Immunofluorescence data suggest that the inhibition of metastatic tumor growth is attributed to the immune remodeling triggered by PTT and chemotherapy. This work demonstrates a new paradigm of utilizing PTT together with hypoxia-activated drugs to effectively retard metastatic tumor growth.

Recently, ammonia is considered to be an energy medium for hydrogen or energy storage and ammonia/hydrogen can be a potential fuel blend for the spark-ignition engine. Nevertheless, the combustion properties of ammonia/hydrogen mixtures could be distinctive under different initial conditions. In this study, several essential combustion properties, including laminar burning velocity, minimum ignition energy, NOx and ammonia emissions, combustion efficiency, and mixture heating values of ammonia/hydrogen/air premixed combustion were extensively studied under a wide range of equivalence ratios (ϕ), hydrogen fractions (α) and different compression ratio using one-dimensional laminar planar flame and compared with stoichiometric methane, methanol, and ethanol combustion. The behavior of NOx generation changing with ϕ and α was analyzed in detail. Results showed that most properties of ammonia/hydrogen combustion could be comparable to that of hydrocarbon fuels under engine-relevant conditions, except for the mixture heating value is slightly lower in all conditions. Besides, the NO mole fraction non-monotonically changes with ϕ and α due to the competition between the effects caused by the reduction of nitrogen-atom species and the enrichment of H/O radicals. The NO mole fraction of stoichiometric ammonia/hydrogen could be even lower than that of hydrocarbons. Considering the properties of hydrocarbon fuels as a reference, promising working conditions for ammonia/hydrogen mixtures are ϕ from 1.0 to 1.05 and α from 40% to 60%. Besides, a high compression ratio is more suitable for ammonia/hydrogen mixtures due to the excellent knock resistance ability of NH3/H2 and better improvement than hydrocarbon fuels under high compression ratio.

Carbon nanotubes (CNTs), as one-dimensional nanomaterials, show great potential in energy conversion and storage due to their efficient electrical conductivity and mass transfer. However, the security risks, time-consuming and high cost of the preparation process hinder its further application. Here, we develop that a negative pressure rather than a following gas environment can promote the generation of cobalt and nitrogen co-doped CNTs (Co/N-CNTs) by using cobalt zeolitic imidazolate framework (ZIF-67) as a precursor, in which the negative pressure plays a key role in adjusting the size of cobalt nanoparticles and stimulating the rearragement of carbon atoms for forming CNTs. Importantly, the obtained Co/N-CNTs, with high content of pyridinic nitrogen and abundant graphitized structure, exhibit superior catalytic activity for oxygen reduction reaction (ORR) with half-wave potential (E1/2) of 0.85 V and durability in terms of the minimum current loss (2%) after the 30,000 s test. Our development provides a new pathway for large-scale and cost-effective preparation of metal-doped CNTs for various applications.

Recently, lithium metal batteries (LMBs) have regained significant attention as a type of promising rechargeable energy storage device with desired high energy density and long lifetime. Nevertheless, the persistent growth of lithium dendrites during the lithium dripping/stripping process could induce severe safety issues and shorten the lifespan of LMBs, limiting their practical application. In this work, we designed a polymeric one-side conductive Janus separator with preferably oriented pores to effectively reduce the local current density of the electrode and thus minimize the active sites for the germination of lithium dendrites, while also simultaneously enhancing the ionic conductivity to stabilize the Li anode. Such Janus separators could be facilely fabricated from polyvinyl alcohol (PVA) and polyaniline (PANI) precursor aqueous solutions via directional freezing and phase inversion. Our characterization results show that the Janus separator exhibits good surface electrical conductivity on its PANI side and much enhanced ion conductivity owing to the preferably oriented pores and high porosity and also displays a good balance of flexibility and stiffness, excellent wrinkle resistance, and high thermal stability. Moreover, it is confirmed that the Janus separator with oriented pores can efficiently retard the growth of lithium dendrites and promote the formation of a uniform and stable solid electrolyte interphase layer. As a result, compared with the reference separators, including a PVA-PANI Janus separator with random pores, the Janus separator with preferably oriented pores provides cells with a stable and long cycling lifespan and a much higher coulombic efficiency. This work provides a promising new approach to safe, stable and high-performance rechargeable LMBs. Agency for Science, Technology and Research (A*STAR) Nanyang Technological University We thank the Agency for Science, Technology and Research and Nanyang Technological University, Singapore, for providing funding and the PhD scholarship.

A series of sulfonated poly(arylene ether ketone sulfone)s polymer having a degree of sulfonation of 80% and a carboxyl group in the side chain (C-SPAEKS) were prepared by polycondensation. The 4-aminopyridine grafted sulfonated poly(arylene ether ketone sulfone)s polymer membranes (SPPs) were prepared by amidation reaction with the carboxyl group to immobilize 4-aminopyridine on the side chain. The 1H NMR results and Fourier transform infrared of SPP membranes demonstrated the successful grafting of the 4-aminopyridine. Proton conductivity, water absorption, swelling ratio, and thermal stability of different proportions of SPP membranes were investigated under the different conditions. With the increase of pyridine grafting content, the methanol permeability coefficient of the membrane decreased significantly from 8.17 × 10−7 cm2s−1 to 8.92 × 10−8 cm2s−1 at 25 °C. And, the proton conductivity and relative selectivity of the membrane were positively correlated with the grafted pyridine content. Among them, the SPP-4 membrane exhibited the highest proton conductivity of 0.088 Scm−1 at 100 °C. The relative selectivity increased from 4.73 × 104 S scm−3 to 9.84 × 104 S scm−3.

Summary High-level quantum mechanics (QM) methods are no doubt the most reliable approaches for the prediction of atomic charges, but it usually needs very large computational resources, which apparently hinders the use of high-quality atomic charges in large-scale molecular modeling, such as high-throughput virtual screening. To solve this problem, several algorithms based on machine-learning (ML) have been developed to fit high-level QM atomic charges. Here, we proposed DeepChargePredictor, a web server that is able to generate the high-level QM atomic charges for small molecules based on two state-of-the-art ML algorithms developed in our group, namely AtomPathDescriptor and DeepAtomicCharge. These two algorithms were seamlessly integrated into the platform with the capability to predict three kinds of charges (i.e. RESP, AM1-BCC and DDEC) widely used in structure-based drug design. Moreover, we have comprehensively evaluated the performance of these charges generated by DeepChargePredictor for large-scale drug design applications, such as end-point binding free energy calculations and virtual screening, which all show reliable or even better performance compared with the baseline methods. Availability and implementation The data in the article can be obtained on the web page http://cadd.zju.edu.cn/deepchargepredictor/publication. Supplementary information Supplementary data are available at Bioinformatics online.

In this study, phosphotungstic acid-encapsulated MIL-101 (Fe) (HPW@MIL-100 (Fe)) was synthesized by the in-situ direct hydrothermal method. Due to the large mesoporous cages and small microporous windows of MIL-100 (Fe), HPW could be well loaded and confined in the cages of MIL-100 (Fe). Furthermore, novel hybrid proton exchange membranes were fabricated by incorporating HPW@MIL-100 (Fe) into sulfonated poly (arylene ether ketone sulfone) containing carboxyl groups (C-SPAEKS) matrix. The structures of MIL-100 (Fe), HPW@MIL-100 (Fe), C-SPAEKS, and hybrid membranes were characterized by XRD and FT-IR. The HPW@MIL-100 (Fe), with a large amount of phosphotungstic acid in cages, could enhance the proton conductivities of hybrid membranes. The hybrid membrane with 4% content of HPW@MIL-100 (Fe) achieved a high proton conductivity of 0.072 S cm−1 at 80 °C and 100% relative humidity, which was 1.8 times higher than that of pure C-SPAEKS (0.040 S cm−1) at the same conditions. Meanwhile, the introduced HPW@MIL-100 (Fe) fillers improved the dimensional stability of hybrid membranes. These results indicate that introduction of MIL-100 (Fe) materials loaded with HPW plays an important role in improving the comprehensive performance and this series of hybrid membranes have potential as proton exchange membranes.

Flexible conductive composites can be used as wearable strain sensors, which are widely used in the fields of new-generation robotics, electronic skin, and human detection. However, how to make conductive composites that simultaneously possess flexibility, stretchability, self-healing, and sensing capability is challenging research. In this work, we innovatively designed and prepared a silicone polymer conductive composite. MXenes and amino poly(dimethylsiloxane) were modified by small biomolecules via an esterification reaction and a Schiff base reaction, respectively. The modified MXenes are uniformly dispersed, which endows the composite with good electrical conductivity. The reversibility of multiple hydrogen bonds and imine bonds in the composite system makes it have ideal tensile properties and high-efficiency self-healing ability without external stimulation. The conductive composite containing 10 wt % A-MXenes showed an elongation of 81%, and its mechanical strength could reach 1.81 MPa. After repair, the tensile properties and the electrical conductivity could be restored to 98.4 and 97.6%, respectively. In addition, the conductive composite is further evaluated for the value of wearable strain sensors. Even after cut-healed processes, the conductive composite can still accurately detect tiny human movements (including speaking, swallowing, and pressing). This kind of self-healing MXene/PDMS elastomers based on the modification of small biomolecules has great potential as wearable strain sensors. This simple preparation method provides guidance for future multifunctional flexible electronic materials.

Flash Joule heating (FJH) can convert almost any carbon-based precursor into bulk quantities of graphene. This work explores the morphologies and properties of flash graphene (FG) generated from carbon black. It is shown that FG is partially comprised of sheets of turbostratic FG (tFG) that have a rotational mismatch between neighboring layers. The remainder of the FG is wrinkled graphene sheets that resemble nongraphitizing carbon. To generate high quality tFG sheets, a FJH duration of 30-100 ms is employed. Beyond 100 ms, the turbostratic sheets have time to AB-stack and form bulk graphite. Atomistic simulations reveal that generic thermal annealing yields predominantly wrinkled graphene which displays minimal to no alignment of graphitic planes, as opposed to the high-quality tFG that might be formed under the direct influence of current conducted through the material. The tFG was easily exfoliated via shear, hence the FJH process has the potential for bulk production of tFG without the need for pre-exfoliation using chemicals or high energy mechanical shear.

The presence of two-dimensional (2D) layer-stacking heterostructures that can efficiently tune the interface properties by stacking desirable materials provides a platform to investigate some physical phenomena, such as the proximity effect and magnetic exchange coupling. Here, we report the observation of antisymmetric magnetoresistance in a van der Waals (vdW) antiferromagnetic/ferromagnetic (AFM/FM) heterostructure of MnPS3/Fe3GeTe2 when the temperature is below the Neel temperature of MnPS3. Distinguished from two resistance states in conventional giant magnetoresistance, the magnetoresistance in the MnPS3/Fe3GeTe2 heterostructure exhibits three states, of high, intermediate, and low resistance. This antisymmetric magnetoresistance spike is determined by an unsynchronized magnetic switching between the AFM/FM interface layer and the bulk of Fe3GeTe2 during magnetization reversal. Our work highlights that the artificial vdW stacking structure holds potential to explore some physical phenomena and spintronic device applications.

Background Next generation of coating materials on the surface of implants is designed with a paradigm shift from an inert material to an osteoimmunomodulatory material. Regulating immune response to biomedical implants through influencing the polarization of macrophage has been proven to be an effective strategy. Methods Through anodization and hydrothermal treatment, magnesium ion incorporated TiO2 nanotube array (MgN) coating was fabricated on the surface of titanium and it is hypothesized that it has osteoimmunomodulatory properties. To verify this assumption, systematic studies were carried out by in vitro and in vivo experiments. Results Mg ion release behavior results showed that MgN coating was successfully fabricated on the surface of titanium using anodization and hydrothermal technology. Scanning electron microscopy (SEM) images showed the morphology of the MgN coating on the titanium. The expression of inflammation-related genes (IL-6, IL-1β, TNF-α) was downregulated in MgN group compared with TiO2 nanotube (NT) and blank Ti groups, but anti-inflammatory genes (IL-10 and IL-1ra) were remarkably upregulated in the MgN group. The in vitro and in vivo results demonstrated that MgN coating influenced macrophage polarization toward the M2 phenotype compared with NT and blank-Ti groups, which enhanced osteogenic differentiation of rat bone mesenchymal stem cells rBMSCs in conditioned media (CM) generated by macrophages. Conclusion MgN coating on the titanium endowed the surface with immune-regulatory features and exerted an advantageous effect on osteogenesis, thereby providing excellent strategies for the surface modification of biomedical implants.

Conventional Al Si materials always have a coarse and discontinuous Si structure, which limits their application as thermal management materials. Fortunately, nature has evolved efficient strategies to form complex microstructures that exhibit excellent wear resistance and thermal properties; one such example is found in the red deer antler. Here, inspired by the antler structure, Al Si composites with a novel fenestrated network-particle structure (F N) and with a common isolated island structure (I I) are designed and prepared. Subsequently, the dynamic formation of F N is tracked and studied using computational fluid dynamics (CFD) simulation. To investigate the reinforcement mechanisms of F N, the wear resistances and thermal properties of F N and I I are compared and analyzed. Simulation and experimental results show that the reconstruction of a semi-continuous structure promotes the formation of a striated structure, whereas flowing Si particles provide some sites for the formation of the fenestrated structure. The dynamic formation of F N is strongly influenced by the convection–diffusion process and the flow path. Moreover, this biomimetic F N structure exhibits better wear resistance and thermal properties than I I, owing to its strong structural support and high expansion resistance. This work is expected to provide new perspectives on the microstructural design of thermal management materials with good wear resistance.

In order to improve the performance of anion exchange membrane (AEMs) as the core component of alkaline fuel cell, a novel pentamethyl-contained phenolphthalein multi-arm monomer is synthesized. The highly imidazolium-functionalized poly (arylene ether ketone) membrane (Im-PEK-x) are prepared by introducing 1,2-dimethylimidazole as hydrophilic segments. The monomer, polymer and anion exchange membranes are confirmed by 1H NMR spectra. The well-defined micro-phase separated structure of membranes is conducive to ion transport and the structure is investigated by TEM and SAXS. The imidazolium-functionalized membranes (Im-PEK-0.8) exhibits high ionic conductivity (0.148 S/cm at 80 °C). The tensile strength of Im-PEK-0.8 membrane is 30.06 MPa. Furthermore, after immersing in 60 °C, 2 M NaOH solution for 240 h, the ionic conductivity remains 0.092 S/cm for Im-PEK-0.8. The 1,2-dimethylimidazole enhance alkaline stability by steric effect of the substituent group at the C2 position. All these results indicate that this is a new method to enhance conductivity and stability performance of AEMs.

Creating micro/nanostructures on fibers is beneficial for extending the application range of fiber-based devices. To achieve this using thermal fiber drawing is particularly important for the mass production of longitudinally uniform fibers up to tens of kilometers. However, the current thermal fiber drawing technique can only fabricate one-directional micro/nano-grooves longitudinally due to structure elongation and polymer reflow. Here, we develop a direct imprinting thermal drawing (DITD) technique to achieve arbitrarily designed surface patterns on entire fiber surfaces with high resolution in all directions. Such a thermal imprinting process is simulated and confirmed experimentally. Key process parameters are further examined, showing a process feature size as small as tens of nanometers. Furthermore, nanopatterns are fabricated on fibers as plasmonic metasurfaces, and double-sided patterned fibers are produced to construct self-powered wearable touch sensing fabric, revealing the bright future of the DITD technology in multifunctional fiber-based devices, wearable electronics, and smart textiles., Creating micro/nanostructures on fibers is beneficial to many fiber-based devices, which remains a challenge in large-scale fabrication due to elongation and reflow. Here, the authors demonstrate a method for generating high-resolution, arbitrarily designed surface patterns on fiber during the thermal drawing process.

To avoid crosstalk and suppress leakage currents in resistive random access memories (RRAMs), a resistive switch and a current rectifier (diode) are usually combined in series in a one diode–one resistor (1D–1R) RRAM. However, this complicates the design of next-generation RRAM, increases the footprint of devices and increases the operating voltage as the potential drops over two consecutive junctions1. Here, we report a molecular tunnel junction based on molecules that provide an unprecedented dual functionality of diode and variable resistor, resulting in a molecular-scale 1D–1R RRAM with a current rectification ratio of 2.5 × 104 and resistive on/off ratio of 6.7 × 103, and a low drive voltage of 0.89 V. The switching relies on dimerization of redox units, resulting in hybridization of molecular orbitals accompanied by directional ion migration. This electric-field-driven molecular switch operating in the tunnelling regime enables a class of molecular devices where multiple electronic functions are preprogrammed inside a single molecular layer with a thickness of only 2 nm. A multifunctional molecule acting both as diode and variable resistor is used to fabricate compact molecular switches with a thickness of 2 nm, good current rectification and resistive on/off ratio, and requiring a drive voltage as low as 0.89 V.

Due to the burning of fossil fuels, the level of carbon dioxide(CO2) in the atmosphere gradually rises, leading to serious greenhouse effect and environmental problems. Electrocatalytic reduction of CO2 is currently an efficient way to convert CO2 to value-added products. Bismuth(Bi)-based nanomaterials have raised great interests due to their excellent activity and high selectivity to electrocatalytic CO2 reduction. In this review, the fundamental principles of electrochemical CO2 reduction reaction(CO2RR) are introduced at first. Moreover, the recent development of Bi-based electrocatalytic materials including Bi with various nanostructures(nanoparticle, nanosheet, etc.), Bi-based compounds(Bi oxide, bimetal chalcogenide, etc.), and Bi/C nanocomposites are summarized. In the end, the future prospects and challenges of electrocatalysts for CO2 reduction are discussed.

Through mathematical analysis, the performance of micro tubular solid oxide fuel cell (SOFC) is evaluated successfully, which is in good agreement with the experimental data under different fuel flow. The results show that under the condition of high fuel utilization, a part of current path passing through the anode can increase by 16% compared with that under the condition of low fuel utilization, which can reduce the output performance of the cell. In the process of increasing fuel flow, the current gradually increases and reaches the platform value. When the length of cathode is long and the inner diameter of anode is small, the loss can be effectively reduced by changing the thickness of anode tube.

Hydrogels have attracted growing attention in electronics due to the soft, flexible nature and the ion-rich physiological environment. Herein, we reported a strategy to not only enhance a tradition...

The practice of site control for functional groups to achieve better interactions has become popular in recent years. Capitalizing on such developments, sulfonated 5-carboxybenzotriazole (SCBTA), s...

The report on the superconductivity of the two-legged spin ladders BaFe2S3 and BaFe2Se3 has established 123-type iron chalcogenides as a novel subgroup in the iron-based superconductor family and has stimulated the continuous exploration of other iron-based materials with new structures and potentially novel properties. In this paper, we report the systematic study of a new quasi-one-dimensional (1D) iron-based compound, Ba9Fe3Te15, including its synthesis and magnetic properties. The high-pressure synthesized Ba9Fe3Te15 crystallized in a hexagonal structure that mainly consisted of face-sharing FeTe6 octahedral chains running along the c axis, with a lattice constant of a = 10.23668 A; this led to weak interchain coupling and an enhanced one-dimensionality. The systematic static and dynamic magnetic properties were comprehensively studied experimentally. The dc magnetic susceptibility showed typical 1D antiferromagnetic characteristics, with a Tmax at 190 K followed by a spin glass (SG) state with freezing at Tf ≈ 6.0 K, which were also unambiguously proved by ac susceptibility measurements. Additionally, X-ray magnetic circular dichroism (XMCD) experiments revealed an unexpected orbital moment for Fe2+, i.e., 0.84 μB per Fe in Ba9Fe3Te15. The transport property is electrically insulating, with a thermal activation gap of 0.32 eV. These features mark Ba9Fe3Te15 as an alternative type of iron-based compound, providing a diverse candidate for high-pressure studies in order to pursue some emerging physics.

High ionic conductivity and excellent alkaline stability are very important for solid electrolyte. Therefore, spindle-shaped anion exchange membranes (AEMs) based on poly (arylene ether ketone) and 1-Bromo-N,N,N-trimethylhexane-6-aminium bromide (Br-QA) have been prepared. The obtained Br-QA can be grafted with poly (arylene ether ketone) main chains to form micro-phase separation structure enhancing the ionic conductivity. Especially, the grafting quaternary ammonium (QA) cation groups are separated by alkyl bromine endows the AEMs with alkaline stability features. Simultaneously, the OH− conductivity of the QA-PAEK-0.6 obtained membranes is 0.046 S/cm under fully hydrated conditions at 60 °C. After immersing into 1 M NaOH alkaline solution for 15 days at 60 °C, the anionic conductivity still high to 0.03 S/cm. Meanwhile, the poly (arylene ether ketone) backbones provide excellent mechanical properties and the Br-QA cation groups also possess good thermal stability, which satisfy the requirement of wide applications.

Water environment has great influence on proton dissociation which leads positive contribution to conductivity in direct methanol fuel cells (DMFCs). Here amino propy functionalized mesoporous sili...

Cyano groups have been successfully introduced on the backbone edge of g-C3N4 to fabricate nitrogen defects under mild conditions, which are derived from incomplete polymerization of g-C3N4 after BaCO3 utilization. Characterization results indicate that the interfacial interaction between BaCO3 and carbon nitride is playing a significant role for introducing cyano groups into g-C3N4. Cyano groups working as electron capture centers are proved to change the band gap of carbon nitride, reducing the recombination rate of electron-hole pairs and promoting charge separation. As expected, the hydrogen evolution rate of nitrogen-defect-modified carbon nitride is improved to 71.57 μmol h−1, which is 13.5 times that of pristine C3N4. Meanwhile, the degradation efficiency of methyl orange is promoted (5 times that of pristine C3N4). This work is the first report on the fabrication of cyano-group-modified carbon nitride with BaCO3 utilization, and opens a new door for further exploring environmental-friendly carbon nitrides on energy conversion.

Gaphene assembled film (GAF) has shown great potentials in practical applications. However, it is still a big challenge to reach reliable soldering of GAF at low temperature, and overcome the exfoliation tendency and the electrical loss resulted from anisotropy of GAF. In this work, we developed a rapid low temperature soldering process for GAF inspired by an ultrasonic assistance technology. As a result, Sn solder spots were prepared on the surface of GAF by ultrasonic metallizing treatment for 10 s in molten Sn at 300 °C. The shock waves and micro-jets induced by ultrasonic waves were supposed to improve the poor wettability of GAF, which propelled molten Sn to penetrate into GAF interlayers, and drove Sn atoms to impinge GAF surface to form an amorphous carbon (a-C) layer at GAF/Sn bonding interface. Specially, the penetration bonding between GAF and Sn solder could not only overcome the exfoliation tendency of GAF, but also reduce the electrical loss between GAF interlayers. The GAF/Sn/GAF soldered joints prepared by remelting Sn metallization layers exhibited excellent tensile resistance and electrical conductivity. Such efficient and reliable soldering technology can facilitate the development of high-performance carbon-based materials in electronic industry.

Graphene nanoribbons (GNR) have shown great promise for applications in electronics, sensors, energy-conversion/storage devices, conductive composite materials, and biological fields. Commercialized GNR are mostly produced by unzipping high-quality carbon nanotubes (CNT), predominantly Mitsui CNT. Since the remaining stock of Mitsui CNT is running out, there is an urgent need for a reliable, cost-effective substitute. We studied three different brands of CNT as potential CNT sources in place of Mitsui CNT for making GNR. The NTL CNT and the Saratoga CNT were demonstrated to be well unzipped under both oxidative and reductive conditions based on scanning electron microscopy analysis. Raman and X-ray photoelectron spectroscopy were used to verify the efficacy of the unzipping reactions. The resulting GNR showed improved dispersibility in multiple solvents and similar electrical conductivity compared to the original CNT. The NTL CNT and the Saratoga CNT are expected to become a good substitute for Mitsui CNT in the large-scale production of GNR.

Summary Identification of the structure-performance relationship at the atomic level is vital for getting a deep understanding of the size-dependence behavior of metal catalysts. Here, an unconventional size dependence of Pt toward selective hydrogenation of p-chloronitrobenzene has been extensively investigated over CeO2 support. An upturned volcanic curve toward the selectivity of p-chloroaniline was found by decreasing the size of Pt from nanoparticles to single atoms. Differences on predominant orbitals among diverse coordination-environment Pt sites were identified to be the key factors influencing the modes of interaction with the C-Cl bond of p-chloroaniline. Specifically, electrostatic repulsion between non-bonding orbitals of Cl and predominant orbitals of Pt sites with high steric hindrance were speculated to be responsible for the suppression of dehalogenation and the high selectivity. This strategy to build correlation between the valence orbitals of active sites and their catalytic behavior could well be expanded to other structure-sensitive reactions and atomically dispersed catalysts.

A series of nitrogen doped 3D hierarchically porous carbon beads with size of 0.6–0.9 mm are successfully prepared by one-step pyrolysis of dicyandiamide and macroporous resin under different ratio. Dosage of dicyandiamide can effectively control shrinkage of resins during pyrolysis, and favor to create 3D interconnected pore channels and abundant nitrogen doped sites as a self-sacrificing dopant and activating-like agent. The beads display excellent conversion for ethylbenzene to acetophenone as opposed to only calcinating pristine IRA resins (83.5% vs 12.1%), when the ratio reach 1:1. At initial reaction period, linear relationships between concentration of reactants and products are established to evaluate whether the beads are provided with diffusion limitation in mentioned reaction. Structural characterization and reaction kinetic studies indicate that the larger mesoporous pore volume and more meso/macro-pore structure of the beads can expose more accessible active sites and lower diffusion limitation, significantly affecting the initial rates, thereby improving the catalytic performance. In addition, macro-beads in size of millimeter scale can effectively exert the advantages of easy separation and recovery. A new strategy is provided which can keep the diversity of pore scale in porous carbonous precursors during pyrolysis, thereby more effectively applying in heterogeneous catalysis.

Most bulk-scale graphene is produced by a top-down approach, exfoliating graphite, which often requires large amounts of solvent with high-energy mixing, shearing, sonication or electrochemical treatment1–3. Although chemical oxidation of graphite to graphene oxide promotes exfoliation, it requires harsh oxidants and leaves the graphene with a defective perforated structure after the subsequent reduction step3,4. Bottom-up synthesis of high-quality graphene is often restricted to ultrasmall amounts if performed by chemical vapour deposition or advanced synthetic organic methods, or it provides a defect-ridden structure if carried out in bulk solution4–6. Here we show that flash Joule heating of inexpensive carbon sources—such as coal, petroleum coke, biochar, carbon black, discarded food, rubber tyres and mixed plastic waste—can afford gram-scale quantities of graphene in less than one second. The product, named flash graphene (FG) after the process used to produce it, shows turbostratic arrangement (that is, little order) between the stacked graphene layers. FG synthesis uses no furnace and no solvents or reactive gases. Yields depend on the carbon content of the source; when using a high-carbon source, such as carbon black, anthracitic coal or calcined coke, yields can range from 80 to 90 per cent with carbon purity greater than 99 per cent. No purification steps are necessary. Raman spectroscopy analysis shows a low-intensity or absent D band for FG, indicating that FG has among the lowest defect concentrations reported so far for graphene, and confirms the turbostratic stacking of FG, which is clearly distinguished from turbostratic graphite. The disordered orientation of FG layers facilitates its rapid exfoliation upon mixing during composite formation. The electric energy cost for FG synthesis is only about 7.2 kilojoules per gram, which could render FG suitable for use in bulk composites of plastic, metals, plywood, concrete and other building materials. Flash Joule heating of inexpensive carbon sources is used to produce gram-scale quantities of high-quality graphene in under a second, without the need for a furnace, solvents or reactive gases.

Metal-organic frameworks (MOFs), known for their tailorable porous structures and large specific surface areas, are appealing for electrochromic applications as their abundant pores may greatly benefit the charge transport required for electrochromic switching. Herein, for the first time, a simple, scalable, and cost-effective electrochemical deposition method for fabrication of high-performance and durable MOFs-based electrochromic films with redox-active ligands was developed. The fabricated film can achieve rapid switching speed (both coloration and bleaching time

Graphitic carbon nitride (g-C3N4) possesses unique electronic and optical properties in the visible-light-driven production of H2O2. However, bulk g-C3N4 suffers from inefficient sunlight absorption and low carrier mobility. Herein, P doped g-C3N4 with a hollow sphere architecture was synthesized. The hollow sphere structure provides a large accessible surface area for charge transfer and enhances photo-absorption properties. Particularly, the doped P can regulate the energy band structure with stronger reducibility for O2 activation and accelerate photo-generated carrier separation. Meanwhile, the P heteroatom is beneficial to produce 1,4-endoperoxide species more easily and enhance selectivity for H2O2 synthesis through a two-electron O2 reduction process. The resultant catalyst exhibits a high H2O2 production rate of 174 μmol h−1 g−1 in pure water and 1684 μmol h−1 g−1 with isopropanol as a hole scavenger, which are 7.5 and 11.2 times those of bulk g-C3N4. This work provides a new avenue for the design and modification of other photocatalysts for H2O2 production.

We demonstrated that the formation and solidification of a continuous confined water film played a very important role in changing the elastic modulus of the wet polymer substrate in a nanoindentation process by a coarse-grained molecular dynamics simulation of this process. It was found that as the water content increased, the elastic modulus of the wet polymer substrate showed a non-monotonic change. Relative to the dry polymer substrate, the elastic modulus of the wet polymer first decreased. This is because the appearance of a confined water film caused the force between the polymer substrate and the indenter to change from repulsion to attraction. Subsequently, as the confined water film gradually solidified and then weakened, the elastic modulus of the wet polymer slowly increased and then rapidly increased due to a large number of interstitial water molecules gradually penetrating the polymer substrate. Therefore, it is unreasonable to explain the wet polymer degradation during nanoindentation only from the plasticization and anti-plasticization effects based on the hydrogen bond breaking and formation during stretching. The above-mentioned results will help to more comprehensively understand the degradation mechanism of the polymers' encounter with water, thus promoting further practical applications for polymers.

Sulfonated poly (aryl ether ketone sulfone) polymers (SPAEKS-PSA X) with the comb-shaped structure were prepared by grafting with 1, 3-propanesultone (PSA). The successful synthesis of SPAEKS-PSA X was confirmed by the FT-IR spectra. The morphology of the membrane was investigated by the small angle X-ray scattering and the transmission electron microscopy. The nanophase separation was brought in a comb-shaped structure between the main chains and the propyl sulfonic acid groups. The SPAEKS-PSA 15 membrane exhibited the highest conductivity of 101 mS cm−1 under 80 °C and 100% relative humidity conditions (100% RH). In addition, the methanol permeability coefficients of SPAEKS-PSA X membranes (7.56 × 10−7 to 9.44 × 10−7 cm2 s−1) were much lower compared to Nafion®117 (22.37 × 10−7 cm2 s−1). Meanwhile, the SPAEKS-PSA X membranes also displayed excellent mechanical properties (tensile modulus >30 MPa), thermal, oxidative stabilities and fuel cell performance. Considering the parameters above, especially the elevated proton conductivities as well as high methanol resistance, the comb-shaped structure is a promising design for DMFCs applications.

Rechargeable zinc-air batteries (ZABs) are attracting enormous attention owing to their low cost and high theoretical energy density. However, their practical applications are impeded by the low lifetimes and inferior energy conversion efficiency as a result of poor catalyst stability and sluggish oxygen reaction kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at their air cathode. Herein, a multiscale structural engineering of the novel catalyst of Fe/Co single atoms co-doped graphite nanoarrays mounted on carbon microspheres (FeCo(a)-ACM) is reported towards ORR and OER for ZABs. In micro-scale, 3D hierarchically porous carbon microspheres facilitate the mass and electron transport; in nano-scale, ordered graphite nanoarrays increase the accessible chances of the active sites; in atomic-scale, chemical doping of Fe/Co single atoms boost the intrinsic ORR and OER activity and finally enhance the performance of ZABs. The FeCo(a)-ACM exhibits excellent ORR (onset potential: 1.03 V, half-wave potential: 0.90 V) and OER (1.60 V at 10 mA cm−2) activity. In a practical demonstration, a low charge-discharge gap and a record rechargeable lifetime lasting 900 h at 10 mA cm−2 are achieved by zinc-air battery with FeCo(a)-ACM within the air electrode.

PEM (Polymer Electrolyte Membrane) fuel cells have the potential to reduce our energy use, pollutant emissions, and dependence on fossil fuels. In the past decade, significant advances have been achieved for commercializing the technology. For example, several PEM fuel cell buses are currently rated at the technical readiness stage of full-scale validation in realistic driving environments and have met or closely met the ultimate 25,000-h target set by the U.S. Department of Energy. So far, Toyota has sold more than 4000 Mirai PEM fuel cell vehicles (FCVs). Over 30 hydrogen gas stations are being operated throughout the U.S. and over 60 in Germany. In this review, we cover the material, design, fundamental, and manufacturing aspects of PEM fuel cells with a focus on the portable, automobile, airplane, and space applications that require careful consideration in system design and materials. The technological status and challenges faced by PEM fuel cells toward their commercialization in these applications are described and explained. Fundamental issues that are key to fuel cell design, operational control, and material development, such as water and thermal management, dynamic operation, cold start, channel two-phase flow, and low-humidity operation, are discussed. Fuels and fuel tanks pertinent to PEM fuel cells are briefly evaluated. The objective of this review is three fold: (1) to present the latest status of PEM fuel cell technology development and applications in the portable and transportation power through an overview of the state of the art and most recent technological advances; (2) to describe materials and water/thermal transport management for fuel cell design and operational control; and (3) to outline major challenges in the technology development and the needs for fundamental research for the near future and prior to fuel cell world-wide deployment.

Glycosylation, which is catalyzed by UDP-glycosyltransferases, represents one of the most common modifications in plant secondary metabolites and plays significant roles in plant physiology. While the roots and rhizomes of R. yunnanensis Diels are the well-known traditional Chinese medicine “Xiaohongshen” and R. yunnanensis is rich in different types of glycoside natural products, no glycosyltransferase has yet been molecular genetically and biochemically explored before. Here we report the discovery and characterization of four new glycosyltransferases (GTs), RyUGT3A, RyUGT3B, RyUGT11, and RyUGT12 that mediated anthraquinone glycoside biosynthesis, from the transcriptome of R. yunnanensis. RyUGT3A and RyUGT12 are regioselective glycosyltransferases of β-OH anthraquinones and showed broad substrate promiscuity toward at least 28 compounds to form O-, N-, and S-glycosides. Through the developed one-pot transglycosylation reaction, 18 glycoside congeners, including four new ones, were produced. Molecular modelling and site-directed mutagenesis further revealed the critical residues for substrate binding and glycosylation. The expression profiles of these four GTs with or without methyl jasmonate (MeJA) induced provided a reasonable genetic explanation for the phenomenon that the anthraquinone glycosides are majorly accumulated in the roots of R. yunnanensis. Finally, the subcellular localization of RyUGT3A and RyUGT12 showed that both enzymes were located in the cytomembrane and nucleus. This study expands the growing toolbox of novel glycosyltransferases that could be exploited as practical biocatalysts and provides insights into the continued exploration of other family enzymes in this traditional Chinese medicine as well.