Langmuir最新文献

{"title":"Perspective of Tribological Mechanisms for α-Alkene Molecules with Different Chain Lengths from Interface Behavior","authors":"Xiaolong Liu, Zhiwen Zheng, Juhua Xiang, Hanwei Wang, Haizhong Wang, Dapeng Feng, Dan Qiao, Hansheng Li","doi":"10.1021/acs.langmuir.4c03592","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03592","url":null,"abstract":"Three α-alkene lubricants, differentiated by chain length, were selected as model compounds to investigate the influence of chain length on tribological properties. The novelty of this study lies in setting chain length as the sole variable to explore its impact on surface and adsorption energy. Based on the above findings, the study provides a unique explanation of the intrinsic relationship between chain length and tribological performance. The tribological properties of the three α-alkenes were compared, and subsequent characterization methods elucidated the wear mechanisms and explored tribochemical reactions. The study employed the Owens–Wendt–Rabel–Kaelble (OWRK) method and density functional theory (DFT) to investigate each compound’s surface energy and adsorption energy. Experimental results revealed that the average friction coefficients (abridged as COF) for 1-decene, 1-tetradecene, and 1-octadecene decreased sequentially to 0.125, 0.099, and 0.075, respectively. The wear volume of 1-tetradecene decreased by 53.2% and that of 1-octadecene decreased by 64.0% compared to 1-decene. This can be attributed to the simultaneous enhancement of the surface energy and adsorption energy with increasing chain length. On the one hand, the increase in surface energy facilitates tribochemical reactions positively influencing the formation of tribofilms. On the other hand, the increase in adsorption energy enhances the adsorption of lubricants on the substrate surface. The synergy of these two effects allows 1-octadecene and 1-tetradecene (long-chain α-alkenes) to exhibit superior tribological performance compared to that of 1-decene (short-chain α-alkenes). Ultimately, this study offers unique insights into understanding lubrication mechanisms.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Surface Adsorption on DNA Structure and Stability: Implications for Environmental DNA Interactions with Iron Oxide Surfaces","authors":"Eshani Hettiarachchi, Vicki H. Grassian","doi":"10.1021/acs.langmuir.4c02501","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02501","url":null,"abstract":"Environmental DNA (eDNA), i.e., DNA found in the environment, can interact with various geochemical surfaces, yet little is known about these interactions. Mineral surfaces may alter the structure, stability, and reactivity of eDNA, impacting the cycling of genetic information and the reliability of eDNA-based detection tools. Understanding how eDNA interacts with surfaces is crucial for predicting its fate in the environment. In this study, we examined the surface interaction and stability of herring testes DNA, a model system for eDNA, on two common iron oxide phases present in the environment: α-FeOOH (goethite) and α-Fe₂O₃ (hematite). Utilizing spectroscopic probes, including attenuated total reflection Fourier-transform infrared (ATR-FTIR) and UV–vis spectroscopy, we quantified the DNA adsorption capacity at pH 5 and determined its secondary structure. DNA adsorbed irreversibly at pH 5 and 25 °C, primarily through its phosphate groups, and retained the solution-phase B-form structure. However, the infrared data also indicated some distortion of the B-form likely due to additional interactions between nitrogenous bases when adsorbed on the α-Fe₂O₃ particle surfaces. The distortion in the double helical structure of adsorbed DNA on α-Fe₂O₃ led to a lower melting temperature (<i>T</i>_m) of 60 °C compared to 70 °C for DNA in solution. In contrast, DNA adsorbed on α-FeOOH melted at higher temperatures relative to solution-phase DNA and in two distinct phases. Upon testing adsorbed DNA stability at higher pH values, there were distinct differences between the two iron oxide phases. For α-FeOOH, nearly 50% of the DNA desorbed from the surface when the solution pH changed from 5 to 8, while less than 5% desorbed from α-Fe₂O₃ under the same conditions. Overall, these findings underscore the importance of mineral-specific eDNA–surface interactions and their role in adsorbed eDNA stability, in terms of DNA melting and the impact of solution-phase pH changes.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"53 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cavitation, Hydrophilicity, and Sorption Hysteresis in C–S–H Pores: Coupled Effects of Relative Humidity and Temperature","authors":"Fatima Masara, Farid Benboudjema, Tulio Honorio","doi":"10.1021/acs.langmuir.4c03223","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03223","url":null,"abstract":"Sorption processes are critical for the drying and durability of cement-based materials, directly affecting their thermal properties. Temperature can substantially influence these processes. This work uses molecular simulations to study sorption in C–S–H pores under varying temperatures and relative humidity, considering pore sizes from the gel to the interlayer scale (between 11.6 and 106 Å). We quantify the temperature and pore-size dependence of water cavitation and sorption hysteresis in the C–S–H pores. The critical pore sizes for the disappearance of hysteresis and the reversibility of capillary condensation are identified, with the former being directly associated with cavitation. We show that cavitation occurs only in gel (meso)pores when they are above the critical pore size and below the critical temperature for cavitation. Interlayer pores, a major class of micropores in C–S–H, are not subjected to cavitation. Cavitation in C–S–H pores is homogeneous, occurring in the bulk-like zone of mesopores. The hydrophilicity of the C–S–H surface increases with the temperature, making heterogeneous cavitation less likely to occur. The results above were obtained consistently with three different force field parametrizations, building confidence in their relevance to describe C–S–H interfacial behavior. Finally, we demonstrate that macroscopic considerations for pore emptying and filling, such as the Kelvin-Cohan and equilibrium Derjaguin-Broekhoff-de Boer equations, are not valid or inaccurate when desorption occurs through cavitation in C–S–H. These results are relevant to understanding the sorption processes in other nanolayered adsorbing materials.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"22 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tailored Lead-Free KNN/BFO Perovskite Ferroelectric Film Heterostructures for Enhanced Electrofunctional Properties via Interface-Modulated Bilayer Design","authors":"Wei Zhang, Bowen Peng, Qian Xu, Xinyi Li, Limin Kang, Xuehua Zhang, Fangren Hu","doi":"10.1021/acs.langmuir.4c04326","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04326","url":null,"abstract":"In this work, a bilayer lead-free perovskite ferroelectric structure was fabricated comprising a highly polar BiFeO₃ (BFO) bottom layer and a less polar (K_1–xNa_<i>x</i>)NbO₃ (KNN) top layer. The BFO sublayer, deposited via radio frequency magnetron sputtering without postgrowth annealing, not only exhibited enhanced crystallinity but also promoted superior microstructural properties in the sol-gel derived KNN overlayer, thereby ensuring excellent intrinsic electrical properties. Compared to the poorly crystallized single-layer KNN films directly synthesized on LNO-buffered (100)-Si substrate, the KNN layer in the bilayer structure demonstrated a strong (100) texture, along with a dense, homogeneous, fine-grained morphology. The bilayer design effectively balances the limited polarization of single-layer KNN and the weak dielectric response of single-layer BFO. Furthermore, variations in BFO sublayer thickness reveal that the KNN/BFO stacking configuration and interface characteristics play a crucial role in tailoring the electrical properties, even surpassing the intrinsic contributions of the individual layers. The presence of the BFO layer enhanced the unsaturated polarization in the KNN film, with a more pronounced effect as the BFO thickness increased. The dielectric constant of the KNN/BFO bilayer consistently fell between those of the two single-layer structures and decreased with increasing BFO thickness, contrary to the trend observed in single-layer BFO. These results underscore the complex interactions among intrinsic properties, stacking configurations, and interface coupling in lead-free ferroelectric films, providing insights for future heterostructure design strategies.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"261 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrochemiluminescence of N,N′-Dimethylformamide Passivated Black Phosphorus Quantum Dots","authors":"Shuijian He, Weihan Li, Minsi Li, Zhenlu Liu, Xueliang Sun, Zhifeng Ding","doi":"10.1021/acs.langmuir.4c03095","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03095","url":null,"abstract":"Black phosphorus quantum dots (BPQDs) have shown promising applications in biosensors and energy storage devices. However, the electrochemiluminescence (ECL) properties of pristine BPQDs in an organic system have rarely been reported. In this paper, <i>N</i>,<i>N</i>′-dimethylformamide passivated BPQDs with a small size of 2.3 nm were obtained by an ultrasonication-assisted liquid exfoliation process, and their ECL properties of BPQDs were studied. A reversible reduction peak was recorded by differential pulse voltammetry, while no apparent oxidation peak was observed. ECL signal was not seen in the annihilation route. Persulfate was proved to be an effective coreactant and yellow emission was observed which was greatly red-shifted in comparison to that of photoluminescence. ECL of BPQDs is believed to be generated from both the surface states and electron promotion over their band gap.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"90 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of 2-Mercapto-1-methylimidazole on the Dual Action of Chemical Mechanical Polishing of Cu and Ta","authors":"Xuhua Chen, Ru Wang, Zhanjie Du, Yu Zhu, Zhe Liang, Yanwei Dong, Tao Zheng","doi":"10.1021/acs.langmuir.4c03686","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03686","url":null,"abstract":"When chemical mechanical polishing (CMP) of tantalum (Ta)-based barrier layers is done through silicon via (TSV), it is necessary to control the rate selection of copper (Cu) and Ta to prevent the formation of dishing pit formation due to the rapid removal rate (RR) of copper in the via compared to tantalum outside the via. This paper selected 2-mercapto-1-methylimidazole (TAMZ) as an inhibitor, which has the dual effect of reducing the RR of Cu and increasing the RR of Ta. The experimental results show that the rate selection ratio of Cu and Ta is up to 2.12:1, the inhibition rate of TAMZ on Cu is up to 98.37%, and it can control Cu–Ta galvanic corrosion; the mechanism of TAMZ on Cu and Ta was studied by XPS, SEM, AFM, and other experiments. Theoretical calculation found that TAMZ formed chemical bonds with the metal surface mainly through N and S atoms and could be adsorbed on the surface of Cu and Ta by mixed adsorption, which clarified the inhibition mechanism of TAMZ from a microscopic perspective.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"11 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamic Analysis of Mixed Adsorbed Film and Micelle Compositions above Critical Micelle Concentration","authors":"Hiroki Matsubara, Haruka Matsuura, Akio Ohta, Norihiro Ikeda","doi":"10.1021/acs.langmuir.4c03954","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03954","url":null,"abstract":"In this paper, we proposed a thermodynamic procedure to evaluate binary surfactant mixed adsorbed film and mixed micelle compositions above critical micelle concentrations. This theory first calculates the change in the molar ratio of two surfactants in monomer and micelle states based on the phase-separation model and then imposes the chemical equilibrium between the mixed adsorbed film and mixed micelle of known composition and concentration. We applied this theory to a cationic–nonionic surfactant mixed system, and the relationship between the calculated mixed adsorbed film composition and foam film stability was discussed using the DLVO theory.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"30 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Dynamics Simulation of the Effect of Shale Wettability on CO2 Enhanced Oil Recovery","authors":"Hongxu Fang, Xiaokun Yue, Lu Wang, Sen Liu, Huili Zhang, Fei Feng, Xue Gao, Zhaojie Wang, Shuxian Wei, Xiaoqing Lu, Siyuan Liu, Weifeng Lyu","doi":"10.1021/acs.langmuir.4c04211","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04211","url":null,"abstract":"The wettability of shale is an important factor affecting oil and gas extraction, and conventional experimental methods are difficult to study at the nanoscale. Moreover, most existing studies are qualitatively based on the wettability of rock surfaces with little consideration for their impact on the CO₂-EOR. This study employs molecular dynamics simulation methods to conduct an in-depth analysis of the role of rock surface wettability in the CO₂-enhanced oil recovery (EOR) process. The research findings indicate that as the surface hydroxyl content increases, the adsorption affinity for CO₂ is enhanced, with the selectivity increasing exponentially from 0.74 in the strongly oleophilic wetting (SOW) pore to 3.62 in the strong hydrophilic wetting (SHW) pore. Additionally, variations in wettability result in different types of CO₂ displacement. As oil wettability decreases, the contact interface between CO₂ and oil changes from a convex to a concave shape. Moreover, different types of wettability result in different dynamic contact angle changes over time, which significantly impacts various displacement stages. A comprehensive comparison shows that pores exhibiting oil-wet characteristics reduce the efficiency of the CO₂-EOR. Finally, the investigation explored the influence of pore structure on oil displacement efficiency. In double pores, when the larger pores exhibit hydrophobic characteristics, they further accelerate the displacement speed of the smaller pores. In connected pores, the presence of notch speeds up the displacement effect within the smaller pores, reducing the impact of wettability on displacement efficiency. This study deeply analyzes the role of shale surface wettability in the CO₂-EOR process, revealing the impact of wettability on the CO₂ adsorption affinity, fluid displacement, oil displacement efficiency, and flow characteristics of shale oil, providing an important theoretical basis for optimizing the CO₂-EOR process by adjusting wettability.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"47 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative Silica Acorn Core–Shell Nanostructures: Morphological Control and Applications in Chromatography","authors":"Khalid M. Alotaibi, Anfal A Alkhamees, A. Yacine Badjah Hadj Ahmed, Ahmad Aqel, Abdullah Mohammed Alswieleh","doi":"10.1021/acs.langmuir.4c04046","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04046","url":null,"abstract":"This study introduces the synthesis and characterization of advanced silica core–shell nanostructures, with an emphasis on the innovative Si-ACS (Silica Acorn Core–Shell) design and its modified counterparts. Employing the classic Stöber method, SiCore particles were first produced, followed by the creation of the acorn-like Si-ACS structures. A key aspect of this research is the exploration of the effects of CTAB and TEOS concentrations on the morphology and properties of the silica shells. The study reveals that surfactant concentration influences shell morphology from corn-like to uniformly thin structures, as well as the shell thickness. Specifically, increasing the CTAB concentration from 45.8 mM to 166.9 mM increased the silica shell thickness from 160 to 280 nm, demonstrating the significant impact of surfactant concentration on shell formation. Si-ACS particles exhibited a surface area of 55.54 m²/g and a pore volume of 0.64 cm³/g, as evidenced by BET measurements, indicating successful mesopore formation critical for catalytic and adsorption applications. The materials were further modified with cholesterol and tetraethyl pentaamine (TEPA), which was confirmed by FT-IR analysis. Additionally, the study demonstrates the application of these functionalized nanostructures as chromatographic columns. In particular, the dual-mode interactions of Si-ACS-CHOL-TEPA significantly improve the separation of phthalate esters, thereby highlighting the potential of these materials in advanced analytical and biotechnological applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"256 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Polymer Chain Diffusion Behavior in Thin Slits Formed by Patch-Patterned Surfaces: Influence of Patch Properties","authors":"Hao-Nan Zhang, Guo-Ao Wang, Hang-Kai Qi, Qing-Hui Yang, Meng-Bo Luo","doi":"10.1021/acs.langmuir.4c04264","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04264","url":null,"abstract":"The diffusion dynamics of polymer chains within a narrow slit formed by two patch-patterned surfaces is investigated utilizing Langevin dynamics simulations. These surfaces feature periodically arranged attractive patches of size <i>L</i> and period <i>d</i>, with a staggered configuration of (0.5<i>d</i>, 0.5<i>d</i>) offsets along the <i>x</i> and <i>y</i> axes. When <i>d</i> is fixed, the polymer chain exhibits normal diffusion over long time scales, with the translational diffusion coefficient <i>D</i>_<i>xy</i> gradually decreasing to zero as <i>L</i> increases. Notably, our findings reveal four distinct diffusion modes: free-diffusion mode for <i>L</i> ≤ <i>L</i>₁, where the polymer chain is mainly in a desorption state; adsorption–desorption mode for <i>L</i>₁ &lt; <i>L</i> ≤ <i>L</i>₂, involving transitions from a single-patch adsorption state to a desorption state; exchange-patch mode for <i>L</i>₂ &lt; <i>L</i> ≤ <i>L</i>₃, where the polymer chain switches between a single-patch adsorption state and an upper-lower double-patch adsorption state by exchanging patches; and nondiffusion mode for <i>L</i> &gt; <i>L</i>₃, where the polymer chain is primarily in a pinned state. Furthermore, as the patch attraction strength ε_ps increases, <i>D</i>_<i>xy</i> decreases due to an increase in the adsorption time of the polymer chain. Simultaneously, critical patch size thresholds <i>L</i>₁, <i>L</i>₂, and <i>L</i>₃, exhibit a decreasing trend. These observations highlight the significant influence of the confining slit and patch properties on the diffusion behavior of polymer chains.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}