Langmuir最新文献

{"title":"Composition Conversion-Induced Disassembly of Amphiphilic ABA Triblock Copolymer Vesicles: A Monte Carlo Study","authors":"Yanqi Zong, Jie Cui, Yuanyuan Han","doi":"10.1021/acs.langmuir.4c04472","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04472","url":null,"abstract":"The composition conversion in block copolymer induced by external stimuli such as light and pH is an effective strategy to trigger the disassembly of vesicles experimentally. Based on this strategy, the disassembly behavior of the A₂B₁₂A₂ triblock copolymer vesicle induced by the composition conversion from B block to C block was studied using Monte Carlo simulation. In this study, a part of the B block in the A₂B₁₂A₂ triblock copolymer was converted to the new block C with weaker hydrophobicity, forming the A₂B_{12–<i>n</i>}C_<i>n</i>A₂ tetrablock copolymer. The composition conversion makes the originally stable vesicle unstable, and after sufficiently long simulation time, the system reached a new equilibrium state. The aggregate morphology of the new equilibrium state was highly dependent on the converted chain length (<i>n</i>). A variety of micelles with novel Janus-type phase-separated microstructures in their hydrophobic parts have been observed in the systems with different <i>n</i>. It should be noticed that those Janus-type micelles cannot be obtained via traditional self-assembly processes from homogeneous states of A₂B_{12–<i>n</i>}C_<i>n</i>A₂ tetrablock copolymers under the same conditions. The simulation results further indicated that the morphological transformation from ABA vesicle to ABCA micelles induced by the composition conversion is reversible.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"17 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056867","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":"Dynamic Behaviors of Droplet Impacts in Dropwise Condensation on Horizontal Tube Bundles.","authors":"Tong Zheng, Yuanbo Liu, Yushan Ying, Qixun Li, Shuaishuai Zhang, Tingting Hao, Rongfu Wen, Xuehu Ma","doi":"10.1021/acs.langmuir.4c04489","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04489","url":null,"abstract":"<p><p>Dropwise condensation offers substantial heat transfer advantages over filmwise condensation, enhancing the industrial condenser efficiency and reducing energy losses. However, the dynamics of condensate droplets on horizontal tube bundles remains complex and insufficiently studied. This paper presents a detailed investigation of the impact of dynamic behaviors of condensate droplets by numerical simulation using the Volume of Fluid model. The droplet Weber number (<i>We</i>^d) between horizontal tube bundles determines the characteristics of droplet impact behaviors. This study examines the effects of tube pitch and contact angle on <i>We</i>^d and its distribution of detached droplets, revealing the transition process of the <i>We</i>^d-dominant factors. Based on visualization results, three dynamic behaviors of condensate droplets impacting the lower tube are identified: attachment, rebound, and breakup. The dominant behaviors of multiple droplets impacting the lower tube under various conditions are clarified through the <i>We</i>^d distribution, leading to the establishment of a droplet impact regime map. Breakup behavior results in a larger proportion of the renewal area, with a maximum exceeding 88.80%, enhancing the surface flushing effect. However, it is essential to mitigate liquid film spreading to prevent the onset of near-FWC. Rebound behavior, characterized by minimal contact times down to 15.40 ms, make it more suitable for tubes that can perform quick self-renew. Finally, based on the characteristics of droplet impact behaviors, guidelines for regulating droplet behavior under different conditions are proposed. The findings provide critical insights for the design of novel dropwise condensers.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143062510","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":"Comparison of Hydrogen Bonded Organic Framework with Reduced Graphene Oxide-Pd Based Nanocatalyst: Which One Is More Efficient for Entrapment of Nitrophenol Pollutants?","authors":"Ladan Alehosein, S. Jafar Hoseini, Mehrangiz Bahrami, S. Masoud Nabavizadeh","doi":"10.1021/acs.langmuir.4c04397","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04397","url":null,"abstract":"In this study, a Pd nanoparticles@hydrogen-bonded organic framework (Pd NPs@HOF) thin film was fabricated at the toluene-water interface. The HOF was formed through the interaction of trimesic acid (TMA) and melamine (Mel) in the water phase, while Pd(0) was produced from the reduction of [PdCl₂(cod)] in the organic phase. The as-synthesized Pd NPs@HOF thin film was demonstrated to be an effective catalyst for the selective reduction of <i>p</i>-nitrophenol and <i>o</i>-nitrophenol to <i>p</i>-aminophenol and <i>o</i>-aminophenol. The porous network of the Pd NPs@HOF introduced strong active sites between Mel, TMA, and Pd(0). Kinetic studies showed that the Pd NPs@HOF catalyst exhibited an enhanced rate of <i>p</i>-nitrophenol and <i>o</i>-nitrophenol reduction in comparison with Pd@reduced-graphene oxide (r-GO) with rates that were 1.7 times faster for <i>p</i>-nitrophenol and 1.5 times faster for <i>o</i>-nitrophenol or even 10 times faster than some Pd-based catalysts, with a maximum conversion of 97.1% which was attributed to the higher porosity and greater surface-to-volume ratio of the Pd NPs@HOF material. Furthermore, π–π stacking interactions enhance the catalytic activity of the Pd NPs@HOF catalyst by increasing the active sites, stabilizing the NPs and trapping the nitrophenols, facilitating the electron transfer, and providing the synergistic effect. Also, contributions of hydrogen bonding, van der Waals forces, electrostatic interactions, and π–σ noncovalent interactions are reasons for better performance of Pd NPs@HOF than Pd/r-GO catalyst with the reduced functional groups.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"59 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055719","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":"Capillary Wave-Assisted Colloidal Assembly","authors":"MaCayla J. Caso, Luis D. B. Manuel, Cameron Bachar, Minerva G. Schafer, Nicholas S. Lombardo, Gloria E. Alvarado, Alona Komarenko, Kiana Manoo, Ali Mehrnezhad, Kidong Park, Kevin M. McPeak","doi":"10.1021/acs.langmuir.4c02794","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02794","url":null,"abstract":"The self-assembly of nanoparticle colloids into large-area monolayers with long-range order is a grand challenge in nanotechnology. Using acoustic energy, i.e., acoustic annealing, to improve the crystal quality of self-assembled colloidal monolayers is a new solution to this challenge, but the characterization of the capillary waves driving the annealing process is lacking. We use a laser Doppler vibrometer and optical diffraction to uncover the frequency-dependent effects of capillary waves on the real-time self-assembly of submicrometer diameter polystyrene nanospheres at an air–water interface. Our study unambiguously demonstrates that low-frequency, e.g., sub-100 Hz, capillary waves are key to improving the long-range order of colloidal monolayers on an air–water interface. Furthermore, we demonstrate how a simple immersion transducer can generate capillary waves and how transducer placement and design affect vibrational spectra. Lastly, we show that frequency-shift keying of a high-frequency focused transducer provides a straightforward method of exciting low-frequency capillary waves that are effective at forming colloidal monolayers with excellent crystal quality, exhibited by grains over 3.5 cm².","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"10 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057322","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":"Construction of Thermal Bridge in Alumina/Polydimethylsiloxane Composites by Selective Location of Erythritol","authors":"Chengyang Tu, Yanjun Zeng, Yuanyuan Zhang, Feiyu Kang, Hongda Du","doi":"10.1021/acs.langmuir.4c04415","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04415","url":null,"abstract":"Alumina/polymer composites are conventional thermal interface materials widely used for heat dissipation. However, the interfacial thermal resistance (ITR) dominates the thermal conductivity (TC) of these composites, presenting a critical challenge. This study introduces erythritol as an innovative thermal bridge to effectively reduce the ITR by selectively locating it at the interfaces among alumina (Al₂O₃) particles. Through a straightforward preparation method, erythritol was positioned among Al₂O₃ particles, followed by the impregnation of poly(dimethylsiloxane) (PDMS) into the filler gaps. The resulting Al₂O₃/erythritol/PDMS composite demonstrated a thermal conductivity of 3.12 W·m^–1·K^–1 at an erythritol content of 4.16 wt % and a filler content of 53.7 vol %. Minor usage of erythritol brings a 34.4% enhancement compared with conventional Al₂O₃/PDMS composites. Additionally, the composite shows potential as a thermal switch due to erythritol’s phase change properties. This approach, which emphasizes fluid-state processing and interface bridging, presents a promising new strategy for improving the thermal conductivity of ceramic-filled polymer composites.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"79 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057323","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":"Cellulose Nanofiber-Reinforced γ-AlOOH Aerogels for Enhanced Removal of Environmental Pollutants","authors":"Prashant D. Sarvalkar, Rajiv S Vhatkar, Kiran Kumar K. Sharma","doi":"10.1021/acs.langmuir.4c04613","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04613","url":null,"abstract":"In this study, we report the modification of a monolithic γ-aluminum oxy-hydroxide (γ-AlOOH) aerogel with cellulose nanofibers (CNFs) using the sol–gel method via supercritical drying. The optimized 2% CNF (w/w) results in a monolithic CNF-γ-AlOOH that is amorphous in nature, along with C–C and C–O–C functional groups. Transmission electron microscopy (TEM) images of the as-synthesized CNF-γ-AlOOH showed CNF embedded in the γ-AlOOH aerogel. The adsorption capacities were determined using azo dyes: methylene blue (MB) and crystal violet (CV), and heavy metal ions: lead [Pb(II)], uranium [U(VI)], and arsenic [As(III)] as models for environmental pollutants. The maximum adsorption capacities were 210 mg/g for CV, 204 mg/g for MB, 105 mg/g for As(III), and 339 mg/g for U(VI) at a pH of 7, whereas Pb(II) exhibited a maximum adsorption capacity of 100 mg/g at pH 5. This is attributed to the synergistic interactions between the CNF hydroxyl groups and γ-AlOOH active sites, facilitating electrostatic and coordination interactions. The as-synthesized aerogels demonstrated high recyclability, retaining over 94% adsorption efficiency after five cycles and offering a sustainable approach to environmental remediation. These findings establish CNF-γ-AlOOH aerogels as robust, eco-friendly materials for water treatment applications, with potential scalability for addressing diverse environmental pollutants. Future research should explore their application in the removal of emerging contaminants and optimize their synthesis for household and industrial-scale implementation.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"18 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057324","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":"Encapsulation of Oil Droplets Using Film-Forming Janus Nanoparticles","authors":"Geosmin Turpin, Duc Nguyen, Kathryn Isobel Sypkes, Christopher Vega-Sánchez, Tim Davey, Brian S. Hawkett, Chiara Neto","doi":"10.1021/acs.langmuir.4c03843","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03843","url":null,"abstract":"Polymer Janus nanoparticles with one hard cross-linked polystyrene lobe and one soft film-forming poly(methyl methacrylate-<i>co</i>-butyl acrylate) lobe were synthesized by reversible addition–fragmentation chain transfer (RAFT)-mediated emulsion polymerization. The Janus nanoparticles adsorbed to oil/water and air/water interfaces, where the soft lobes coalesced, forming films of thickness between 25 and 250 nm; droplets of silicone oil could be stably encapsulated in polymer in this way. When prepared by mechanical mixing without additives, capsules of diameter 5–500 μm could be prepared, and with additives and application of heat, capsules of diameter around 5 μm were achieved, even with highly viscous silicone oil (20,000 cSt). In a microfluidic device, monodisperse capsules of diameter 180 μm could be formed. The particles were weakly surface-active and spontaneously assembled themselves at air/water interfaces. When added into a paint formula, the oil capsules improved the stain resistance of paint films. Silicone oil leakage from the capsules could be mitigated by incubating the capsules with silica nanoparticles, on which silicone oil reacts, creating grafted layers.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"4 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055448","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":"Enantiomer-Dependent Supramolecular Antibacterial Therapy for Drug-Resistant Bacterial Keratitis","authors":"Jingke Yao, Xunjie Shang, Nannan Shao, Hao He, Jiayi Wei, Yingying Huang, Tianxi Shen, Limin Chen, Yunlong Zhou, Wei Chen","doi":"10.1021/acs.langmuir.4c04357","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04357","url":null,"abstract":"Bacteria have the potential to exhibit divergent stereochemical preferences for different levels of chiral structures, including from molecule, supramolecule, to nanomicroscale helical structure. Accordingly, the structure–activity relationship between chirality and bactericidal activity remains uncertain. In this study, we seek to understand the multivalent molecular chirality effect of chiral supramolecular polymers on antibacterial activity. Two <i>n</i>-butylazobenzene-modified <span>l</span>- and <span>d</span>-tripeptides (abbreviated C₄Azo-<span>l</span>-VKK–OH and C₄Azo-<span>d</span>-VKK–OH) were synthesized and subsequently self-assembled in water into chiral supramolecular polymers (designated <span>l</span>-Fiber and <span>d</span>-Fiber, respectively). The <span>l</span>-Fiber and <span>d</span>-Fiber displayed comparable nonhelical nanofiber morphologies but exhibited opposite multivalent molecular chirality. A comparative study demonstrated that the l-Fiber exhibited a markedly higher affinity for bacteria, thereby demonstrating significantly enhanced bactericidal efficiency against methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) in comparison to that of the <span>d</span>-Fiber. Following disassembly into monomers via host–guest chemistry, the bactericidal potency of both the <span>l</span>-Fiber and <span>d</span>-Fiber was found to be almost lost, suggesting the multivalent molecular chirality effect. Of note, the <span>l</span>-Fiber exhibited superior efficacy in curing MRSA-infected keratitis in comparison to the <span>d</span>-Fiber. These findings highlight the importance of multivalent molecular chirality in the design and development of chiral supramolecular polymers for antibacterial applications. This research also presents an effective chiral supramolecular antibacterial strategy for the treatment of drug-resistant bacteria-infected keratitis.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"52 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055716","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":"In Situ Generation of Anatase-Rutile TiO2/g-C3N4 Composite Catalyst in High-Temperature Molten Salt","authors":"Junheng Yingsu, Jianchao Sun, Lingyun Yang, Jiehong Liang, Hongliang Bao, Ling Han, Yuan Qian, Hongtao Liu, Xiaobin Fu","doi":"10.1021/acs.langmuir.4c04971","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04971","url":null,"abstract":"Hydrogen evolution from water, catalyzed by solar energy, is a promising yet challenging endeavor. Small-sized catalysts usually exhibit high utilization and high performance in the hydrogen evolution field. However, the high surface energy tends to make them aggregate. In this study, we introduce a novel molten salt synthesis technique to develop a composite catalyst featuring a TiO₂/C₃N₄ heterojunction to stabilize the small-sized TiO₂. High-temperature molten salts create a highly polarized environment that facilitates the formation of a smaller-sized Ti precursor, thereby enhancing the integration of the heterojunction with C₃N₄ structures and significantly improving the photocatalytic hydrogen evolution performance. Additionally, the oxidation of sacrificial reagents was examined using a quasi-in-situ NMR technique, with a comprehensive discussion of the reaction products and mechanisms. This research offers valuable insights for employing the molten salt approach in the development of photocatalysts and other functional materials.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"94 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055720","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":"Unraveling Ofloxacin Behavior in Aqueous Environments: Molecular Dynamics of Colloidal Formation and Surface Adsorption Mechanisms","authors":"Fatokhoma A. Camara, Hamidréza Ramézani, Nathalie Mathieu, Sandrine Delpeux-Ouldriane, Suresh K. Bhatia","doi":"10.1021/acs.langmuir.4c04265","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04265","url":null,"abstract":"Ofloxacin, a commonly prescribed antibiotic, raises serious environmental concerns due to its persistence in aquatic systems. This study offers new insights into the environmental behavior of ofloxacin and its interactions with carbon-based adsorbents with the aim of enhancing our understanding of its removal mechanisms via adsorption processes. Using a comprehensive computational approach, we analyzed the speciation, pK_a values, and solubility of ofloxacin across various pH conditions, accounting for all four microspecies, including the often-overlooked neutral form. Our findings indicate that clustering of ofloxacin in water is influenced not only by solubility but also by electrostatic repulsion, dipole creation, and π–π interactions. At extreme pH levels, clustering is primarily driven by Coulombic forces and strong π–π interactions between different ofloxacin molecules. Density functional theory (DFT) was employed to optimize the molecular structures, and molecular dynamics (MD) simulations explored interactions among ofloxacin, water, and carbon surfaces. Hybrid Reverse Monte Carlo (HRMC) simulations were used to determine the disordered structure of an activated carbon cloth (ACC), specifically, KIP1200 (Dacarb company, France), for use in MD simulations. KIP1200 contains a small amount of oxygen (less than 2%), which supports our assumption of a predominantly carbon-based structure. Surface interactions were found to vary significantly depending on the ofloxacin form. The neutral form exhibited strong π–π interactions with flat surfaces, whereas the zwitterionic form displayed a greater affinity for curved surfaces. On KIP1200, adsorption was pH-dependent: acidic conditions enhanced adsorption due to reduced repulsion, while adsorption decreased under basic conditions. The aromatic rings in ofloxacin, combined with the high electronegativity of its fluorine atoms, played a critical role in facilitating adsorption through π–π interactions. These results deepen our understanding of ofloxacin microspecies, colloid formation, and adsorption mechanisms under diverse conditions.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"209 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055715","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}