Langmuir最新文献

Fine precipitates formed in steels significantly influence their mechanical properties. However, an accurate evaluation of their size distribution remains challenging. To determine the size distribution of these precipitates, a combination of extraction from steels by the electrolytic dissolution method and asymmetric flow field-flow fractionation (AF4) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) was employed. Dispersing these precipitates in the liquid phase is necessary to achieve an accurate measurement of their size distributions by this method. In this study, a novel approach was established to improve the dispersion state of titanium nitride (TiN) precipitates in the liquid phase by utilizing the Hansen solubility parameter (HSP), enabling accurate size distribution analysis. Following an investigation of the dispersion state of TiN reagent in 29 types of solvents, the Hansen solubility sphere method was applied, and the HSP value was determined to be (δ_d, δ_p, δ_h) = (19.4 ± 0.1, 16.9 ± 0.0, 20.5 ± 0.1). The appropriate relative energy difference (RED) for TiN was examined by changing the RED. It was found that a good dispersion state required a RED of less than 0.76. Furthermore, a solvent mixture of ethylene glycol and dimethyl sulfoxide (RED = 0.50) was applied for transmission electron microscopy observation and AF4-ICP-MS analysis of the TiN precipitates extracted from the steels. Both analyses were successful because of the good dispersion of the TiN precipitates in the solvent mixture. Consequently, this approach can be useful for quantitatively analyzing the size distribution of various fine precipitates in steels by improving the dispersion state in the liquid phase.

The urgent need for sensitive, selective, and rapid detection of nerve agents (NAs), a class of highly toxic organophosphorus compounds, has motivated the development of advanced fluorescent sensing materials. Herein, a series of interpenetrated luminescent metal-organic frameworks (MOFs) with 2,6-naphthalenedicarboxylic acid (NDC) and naphthalenediimide (NDI) or perylenediimide (PDI) ligands were reported, specifically targeting the detection of diethyl chlorophosphate (DCP), a nerve agent simulant. Among them, the 3D Zn-PDI-NDC framework demonstrates a pronounced fluorescence "turn-on" response to DCP with an ultra-low detection limit of 3.6 ppb and high selectivity, even in the presence of potential interferents, which is mainly attributed to ligand conformational reorganization accompanied by host-guest ground-state interactions. On the other hand, Zn-NDI-NDC and Zn-NDC MOFs with similar interpenetrated architectures display distinct fluorescence response behaviors, including fluorescence quenching or weak enhancement, reflecting differences in ligand electronics and host-guest interactions. Such comparative sensing behaviors in structurally related MOF sensors highlight the crucial role of ligand electronics and geometry. Overall, this work presents a PDI-based interpenetrated MOF platform with excellent DCP sensing performance and offers insights into MOF design strategies for organophosphorus nerve agent detection.

The multidentate hybrid C, N donor N-heterocyclic carbene ligand is used to synthesize an unprecedented Ag(I)-NHC complex and afford controllable assembly of an organometallic Ag(I)-Au(I)-NHC complex. Both experimental and theoretical studies were performed to characterize the organometallic linear chain Ag(I)-NHC polymer (2) and trinuclear grid-like heterobimetallic Ag(I)-Au(I)-NHC cluster (3) starting from 3-picolyl-functionalized multitopic NHC ligand 1-methyl-3-(pyridylmethyl)imidazo[1,5-a]pyridin-4-ylium hexafluorophosphate (1·HPF₆). After several spectroscopic studies, including IR, UV-vis, NMR, mass, etc., the final structural characterizations were fully achieved by single-crystal X-ray diffraction, confirming their molecular geometry and coordination environment. Importantly, replacing Ag(I) with sister coinage metal Au(I) led to a distinct transformation from a polymeric linear chain Ag(I) complex, 2, to a well-defined trinuclear Ag(I)-Au(I) mixed metal cluster, 3. Complex 3 leads to a two-dimensional polymer through Au(I)-Au(I) interactions. On the basis of silver and gold chemistry, the optoelectronic properties of 2 and 3 are studied. Current-voltage (I-V) measurements of complexes 2 and 3 reveal Schottky barrier diode (SBD) behavior. Key parameters, including the ideality factor, barrier height, and series resistance, were extracted using thermionic emission (TE) theory. Additionally, space-charge-limited current (SCLC) analysis was employed to determine the charge transport properties, such as the effective carrier mobility and transit time. Notably, Ag(I) complex 2 exhibits higher electrical conductivity compared to that of heterobimetallic Ag(I)-Au(I) complex 3. Our results can be used as a model to understand the optoelectronic properties of other Ag(I) and Au(I) polymeric complexes.

A novel approach for the surface-initiated atom transfer radical polymerization (SI-ATRP) of methoxyethyl methacrylate (MEMA) and 3-azidopropyl methacrylate (AZMA) on macroporous silicon substrates and their postfunctionalization by click chemistry with asymmetric catalysts is presented. Crystalline silicon was first used to monitor the multistep functionalization by quantitative IR-ATR spectroscopy. The attachment of an alkynyl FTIR marker on crystalline silicon demonstrated the effectiveness of the methodology, which was then applied onto macroporous silicon to anchor an enantiopure chromium-salen complex as a first step toward the development of new supported asymmetric organometallic catalysts on silicon-based materials. SEM and EDS measurements clearly show good homogeneity of the polymer growth through the porous layers with a uniform distribution of the catalysts (even deep inside the pores). The successful functionalization of macroporous silicon has confirmed the transferability of the technique to porous materials, highlighting its potential for application to even larger surface area substrates in future catalytic studies.

Owing to their high-specific surface area and low thermal conductivity, nanoporous materials are widely regarded as promising media for adsorbed natural gas (ANG) storage. However, the gas-solid coupling during methane transport within these materials is governed by the coupled effects of temperature and pressure, which traditional theoretical models struggle to accurately quantify. In this work, a multiscale approach is employed. At the nanoscale, molecular dynamics (MD) simulations are performed to quantitatively determine the influence of temperature and pressure on methane adsorption capacity, effective thermal conductivity, and the gas-solid coupling region. Based on these results, a Langmuir adsorption model is refined, and a quantitative correlation for the gas-solid coupling area under varying temperatures and pressures is established. At the macroscale, an effective thermal conductivity predictive model for methane-laden porous media is developed based on established heat transfer theories, incorporating the aforementioned gas-solid coupling effects. Furthermore, by comparing different models, the dominant pressure regimes for distinct coupling mechanisms are clearly identified: at low pressures (P < 2.1 × 10⁵ Pa), heat transfer is dominated by the solid backbone, and the local gas-solid interaction is negligible. Conversely, at high pressures (P > 2.1 × 10⁵ Pa), the local gas-solid interaction becomes a significant mechanism, with its contribution increasing sharply with pressure.

Conjugated microporous polymers (CMPs) have emerged as promising electrode materials for secondary lithium-ion batteries (LIBs), owing to their intrinsic insolubility, structural tunability, permanent porosity, and robust reversibility toward lithium intercalation and deintercalation. However, achieving the simultaneous optimization of capacity, rate performance, and cycling stability remains a long-standing challenge. Herein, we designed a rationally engineered porphyrin-based CMP (NiP-CMP) that integrates multiple electrochemically active sites, including metal-N₄ conjugated macrocycles and conjugated alkyne linkages, within a robust π-conjugated framework. By fine-tuning the polycondensation conditions, NiP-CMP with a high specific surface area (1110 m² g^-1) was obtained, ensuring efficient ion diffusion and charge transport. Benefiting from its well-defined conjugated architecture and abundant electrochemically active centers, NiP-CMP delivers a high specific capacity of ∼702 mA h g^-1 at 0.1 A g^-1, together with a rate capability (355 mA h g^-1 at 1 A g^-1) and long-term cycling stability. This work demonstrates a strategic design that effectively resolves the electrode material "trilemma", achieving high capacity, fast kinetics, and durability simultaneously, and thus offers a viable design paradigm for high-performance organic electrode materials in energy storage applications.

The relentless challenges of uncontrolled zinc dendrite growth and severe interfacial side reactions pose a significant threat to the operation and reliability of aqueous zinc-ion batteries (AZIBs). To counter these challenges, this work introduces a novel multifunctional interfacial layer engineered from diatomite (DIA) on the zinc anode. The hierarchically ordered porous architecture and enhanced surface area of modified diatomite (M-DIA) serve as an ion transport channel to homogenize the Zn²⁺ ion flux, further suppressing dendrite formation. Meanwhile, the hydrophobic layer acts as a robust physical barrier, effectively shielding the zinc surface from the aqueous electrolyte. This concerted mechanism yields a dendrite-free morphology and exceptional corrosion resistance. Consequently, the M-DIA@Zn anode enables remarkably stable symmetric cell cycling stability over 1200 h at 2 mA cm^-2 and 1500 h at 5 mA cm^-2, respectively, and achieves an average Coulombic efficiency of 98.6% in asymmetric cells. When paired with a MnO₂ cathode, the full cell exhibits superior capacity retention (260 mAh g^-1 after 100 cycles) and outstanding rate performance. This work underscores the potential of natural diatomite as a multifunctional interface for stabilizing metal anodes, offering a promising pathway toward high-performance and durable zinc-based energy storage.

Crystalline admixtures promote self-healing in concrete by activating chemical reactions that seal cracks and restore the integrity of the matrix, but the distinct mechanisms of different types make it difficult to achieve both rapid sealing and long-term healing within a single system. To address this challenge, precipitation-type crystalline admixtures (PCAs: sodium bicarbonate, sodium fluorosilicate, and sodium silicate) and chelation-type crystalline admixtures (CCAs: sodium gluconate, sodium maleate, and sodium citrate) were combined to develop a PCA-CCA synergistic healing system for concrete. The healing performance of concrete containing this synergistic system was systematically investigated based on crack morphology, closure ratio, water permeability, water absorption, compressive strength retention, chloride diffusion coefficient, and the microstructural characteristics of repair products. Results demonstrated that the PCA-CCA system substantially improved the self-healing ability of the concrete. After 28 days, ordinary concrete exhibited incomplete healing for cracks narrower than 0.20 mm, whereas the sodium maleate-sodium silicate combination achieved full recovery of cracks up to 0.52 mm. In concrete containing this combination, the water permeability decreased to 0, and water absorption was 37% lower than that of ordinary concrete. For predamaged concrete, the compressive strength retention reached 96.7%, while the chloride diffusion coefficient was only 5.2% higher than that of undamaged concrete. Microscopic analyses revealed that the C-S-H gels generated by sodium silicate and the CaCO₃ deposits induced by sodium maleate were evenly distributed and tightly compacted, which enhanced the overall self-healing performance of the concrete.