Langmuir最新文献

{"title":"Mechanical Properties and Fracture Mechanisms of Nanocomposites of Metal and Graphene with Overlapping Edges","authors":"Lujuan Li, Qianqian Cao, Xin Hu, Yongze Ma","doi":"10.1021/acs.langmuir.4c03746","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03746","url":null,"abstract":"The fracture mechanism and mechanical response of Ni/graphene nanocomposites under nanoindentation are investigated by molecular dynamics simulations. We analyze the effect of the overlapping area on the microstructural transition, HCP atomic fraction, dislocation density, load–displacement relationship, and stress distribution. It was found that the maximum indentation depth of embedded graphene has a nonlinear dependence relation with the overlapping area, and it becomes smaller at the overlapping width comparable to the indenter diameter. The graphene layer is able to hinder the expansion of the dislocation into the interior of the Ni matrix in the initial stage. The densities of HCP atoms and dislocations in the composite gradually increase with increasing indentation depth. The stress concentration tends to cause nucleation of dislocations below the indentation surface. When the graphene is ruptured, the elastic recovery to some extent occurs in the deformed substrate. This work sheds light on modifying the mechanical properties of metal/graphene composites by tuning the overlapping boundary of graphene.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"33 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083734","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":"Heterogeneous Nickel Molybdenum Oxide Nanorods Conjugated Graphitic Carbon Nitride: A Bifunctional Electrocatalyst for Overall Water Splitting","authors":"Shubham Mishra, Vartika Sharma, Vaibhav Kulshrestha","doi":"10.1021/acs.langmuir.4c04651","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04651","url":null,"abstract":"The pursuit of sustainable energy solutions has driven extensive research into efficient and cost-effective water-splitting techniques. This study introduces a straightforward method employing nickel molybdenum oxide NiMoO₄ (NMO) nanorods integrated with graphitic carbon nitride (g-CN) sheets as promising catalysts for water splitting. The integrated coupling between NMO nanorods and g-CN leverages the distinctive properties of both materials to boost robustness as well as effectiveness in catalysis for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). We systematically optimized the nanostructure by adjusting the reduction annealing temperature during calcination to improve HER and OER activities. The NMO@g-CN-600 nanostructured catalyst demonstrates exceptional electrochemical HER activity in acidic media, with an overpotential of 148 mV at 10 mA cm^–2 current density, which is approximately 2.72 times lower than that of bare NMO and 2.97 times lower than pristine g-CN catalysts. Under alkaline conditions, the NMO@g-CN-600 nanostructured catalyst exhibited superior OER activity with an overpotential of 252 mV to reach a current density of 10 mA cm^–2, outperforming bare NMO and pristine g-CN catalysts. Additionally, the nanostructured catalyst demonstrated excellent long-term electrochemical stability with chronoamperometric testing over 50 h in both basic and acidic environments, showing low Tafel slopes for the OER and HER of 97 and 98 mV dec^–1, respectively. Various analytical methods confirmed the successful synthesis and structural stability of prepared catalysts. The outstanding electrocatalytic properties of the NMO@g-CN-600 nanostructured catalyst position it as a feasible choice to platinum-group-based catalysts for overall water electrolysis.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"47 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077042","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":"Soft Wetting Ridge Rotation in Sessile Droplets and Capillary Bridges","authors":"Bo Xue Zheng, Tak Shing Chan","doi":"10.1021/acs.langmuir.4c04667","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04667","url":null,"abstract":"We investigate the deformation of soft solid layers in the presence of sessile droplets or capillary bridges. Unlike models that assume Young’s law governs the contact angle, we incorporate the surface tension balance at the contact line to analyze the rotation of the wetting ridge and the corresponding change in the contact angle. Our findings reveal that the rotation direction of the wetting ridge aligns with the sign of the Laplace pressure. Interestingly, although a softer solid layer typically decreases the contact angle for sessile droplets, a negative Laplace pressure in a hydrophilic capillary bridge pulls the solid–liquid interface, leading to an increased contact angle. A hydrophilic capillary bridge would be expected to move from thicker regions of a soft layer to thinner areas, exhibiting behavior opposite that of a sessile droplet. The interplay between soft layer deformation and contact angle modulation provides valuable insights into controlling droplet motion through elastocapillarity.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"10 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077043","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":"Protein Orientation and Polymer Phase Separation Induced by Poly(methyl methacrylate) Tacticity","authors":"Natalia Janiszewska, Joanna Raczkowska, Katarzyna Gajos, Kamil Awsiuk","doi":"10.1021/acs.langmuir.4c04699","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04699","url":null,"abstract":"Stereochemistry may affect the physicochemical and biological properties of polymer films that are important for their applications, including substrates for the fabrication of protein microarrays. In this study, we investigated the effect of poly(methyl methacrylate) (PMMA) tacticity on the interaction of polymer thin films with proteins and on the phase separation process in blends with poly(<i>tert</i>-butyl methacrylate) (PtBMA). Thin films of isotactic, atactic, and syndiotactic PMMA were studied for topography, surface chemistry, and protein adsorption. Secondary ion mass spectrometry and contact angle measurements revealed a lower surface exposure of polar ester functional groups for iso-PMMA, resulting in the reduced adsorption of albumin and fibrinogen proteins. We also showed that changes in surface chemistry alter the orientation of proteins adsorbed on iso-PMMA through hydrophobic and electrostatic interactions. In addition, blends composed of PMMA and PtBMA, both of different tacticities, were investigated in terms of protein microarray fabrication. The two-dimensional domain structure was obtained by a phase separation process for at-PtBMA blends prepared on silicon substrates modified with amino-silane. Finally, for an isotropic and regular polymer pattern of iso-PMMA/at-PtBMA, the possibility of protein microarray formation on this blend was demonstrated, showing selective adsorption to PtBMA domains and perfect mirroring of the polymer patterns.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"39 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077044","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":"Silica Janus Particle-Based Coating Applicable to Multiple Substrates Shows Durable Superhydrophobicity, Wear Resistance, and Corrosion Inhibition","authors":"Chuangye Wang, Jianing Ge, Mengyu Cui, Jintang Xue, Huili Liu, Xinrong Song, Xinyi Zhang","doi":"10.1021/acs.langmuir.4c05345","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05345","url":null,"abstract":"The present work reports the fabrication of a durable superhydrophobic coating based on silica Janus particles. One side of the silica particles was modified by (3-aminopropyl)triethoxysilane to have a reactive alkylamine group, and the other side was treated with octadecyltrimethoxysilane to be hydrophobic. These Janus particles were held together by binder molecules that reacted with the amines attached to the Janus particles and adhered to different substrates, forming superhydrophobic coatings. The water contact angles of the coatings were higher than 158°, whereas their sliding angles were as low as 2°. Their hydrophobicity was preserved even after 200 cycles of intensive abrasion or after 60 days of immersion in 3.5% NaCl solution, evidencing their durable resistance to abrasion and corrosion. The most remarkable property of the presented Janus silica particle-based coating is that it can strongly adhere to multiple substrates such as active metal aluminum, flat substrate glass, biological material wood, and organic polymer with low surface energy polyperfluoroethylene. Moreover, the hydrophobicity, antiwear resistance, and corrosion inhibition ability of the fabricated coating were independent of the substrates. This superiority enables this coating to cover many substrates with different surface properties to fulfill a variety of technical demands.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"125 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077045","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 Electrochemical Nano-Robot: Integrating Printed Nanoelectronics with a Remote-Controlled Robotic for On-Site Underwater Electroanalysis","authors":"Shima Kamran Haghighi, Saba Mohammadlou, Shayan Angizi, Amir Hatamie","doi":"10.1021/acs.langmuir.4c05035","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05035","url":null,"abstract":"Smart and remote sensing technologies offer significant advantages across various applications. This study introduces an innovative approach integrating printed electrochemical nanosensors with a remotely controllable underwater robot, creating a “Robo-sensor” for underwater and surface water sensing. Unlike conventional underwater sensors, the Robo-sensor operates in three dimensions, both on the surface and underwater, targeting specific locations such as coastal areas and deep-sea environments while transmitting data to an external analytical unit. To achieve this, we developed a conductive nanoink by combining graphite, silver nanorods (AgNRs; diameter: 30 ± 20 nm, length: 2 ± 0.2 μm), nail polish as a cohesive agent, and an organic solvent. This ink was used to fabricate an electroanalytical system on the mini-robot’s body. The Robo-sensor, connected to a portable potentiostat, demonstrated linear responses to hydroquinone (HQ) and nitrite ions, with detection ranges of 5.0–1356.0 and 3.0–1200.0 μM, respectively, under artificial seawater conditions (High salinity). Its repeatability (RSD &lt;6%), stability (up to 40 continuous applications with an error &lt; ± 10%), and sensitivity were thoroughly evaluated. The Robo-sensor’s practical applications included detecting chemical leaks in underwater pipelines containing HQ, a hazardous chemical relevant to coastal industries such as petrochemicals. Additionally, it analyzed surface water contaminated with NO₂^– near and far from a wastewater discharge pipeline, providing valuable insights for environmental and ecosystem investigations. In conclusion, the developed Robo-sensor enables on-site analysis both on the surface and underwater, reducing time, costs, and risks in high-hazard environments like deep waters. With further modifications, this strategy could be adapted for diverse applications, including offshore oil and petrochemical operations, corrosion studies, and underwater environmental monitoring, thus expanding the real-world impact of electrochemical science.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"59 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083787","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":"Experimental Study of Gas–Liquid Compound Droplet Impact on Superhydrophobic Surface","authors":"Lei Xing, Jinming Zhang, Yang Gao, Minghu Jiang, Lixin Zhao, Shuai Guan","doi":"10.1021/acs.langmuir.4c04983","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04983","url":null,"abstract":"The impact dynamics of gas–liquid compound droplets (GLCD) on surfaces play a crucial role in optimizing processes such as atomization, coating, and microencapsulation. The dynamic behaviors of GLCD impacting superhydrophobic surfaces under varying impact heights, viscosities, and gas–liquid volume ratios (Φ) were investigated via high-speed photography. Three collision categories are defined according to GLCD morphology evolution under different parameters, i.e., oscillation-breakup, rebound collision, and impact-breakup. As the impact height increases, the occurrence of droplet breakup shifts progressively from the retraction stage to the spreading stage. Notably, the maximum rebound coefficient of the compound droplet initially increases and then decreases with increasing impact height, and finally increases again due to the bubble breakup, which differs from the behavior of the homogeneous droplets. Furthermore, the maximum spreading and rebound heights of the GLCD are suppressed by increasing the liquid-phase viscosity. For Φ = 0.48 GLCD, increasing the liquid-phase viscosity from 4.7 to 5.5 mPa·s raises the critical breakup impact height from 90 mm to 120 mm. Meanwhile, the average dimensionless breakup time also increases from 0.54 to 1.72. As the Φ increases, the liquid film of the GLCD gradually thins, resulting in a decrease in the maximum spreading coefficient and enhanced probability of droplet breakup. Additionally, increasing the Φ from 0.48 to 0.56 leads to an increase in the average dimensionless breakup time by 0.88. This study provides a fundamental understanding of the dynamic behavior of compound droplets and offer valuable insights for related engineering applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"36 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083785","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":"A Free Energy Model for the Plateau Shear Modulus in Thermosensitive Microgel Suspensions","authors":"Maxime Bergman, Yixuan Xu, José Muñéton Díaz, Chi Zhang, Thomas G. Mason, Frank Scheffold","doi":"10.1021/acs.langmuir.4c04528","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04528","url":null,"abstract":"Polymer microgels exhibit intriguing macroscopic flow properties arising from their unique microscopic structure. Microgel colloids usually comprise a cross-linked polymer network with a radially decaying density profile, resulting in a dense core surrounded by a fuzzy corona. Notably, microgels synthesized from poly(<i>N</i>-isopropylacrylamide) (PNIPAM) are thermoresponsive and capable of adjusting their size and density profile based on temperature. Above the lower critical solution temperature (<i></i><math display=\"inline\"><msub><mrow><mi>T</mi></mrow><mrow><mi>LCST</mi></mrow></msub><mo>∼</mo><mn>33</mn></math> °C), the microgel’s polymer network collapses, expulsing water through a reversible process. Conversely, below 33 °C, the microgel’s network swells, becoming highly compressible and allowing overpacking to effective volume fractions exceeding one. Under conditions of dense packing, microgels undergo deformation in distinct stages: corona compression and faceting, interpenetration, and finally, isotropic compression. Each stage exhibits a characteristic signature in the dense microgel suspensions’ yield stress and elastic modulus. Here, we introduce a model for the linear elastic shear modulus by minimizing a quasi-equilibrium free energy, encompassing all relevant energetic contributions. We validate our model by comparing its predictions to experimental results from oscillatory shear rheology tests on microgel suspensions at different densities and temperatures. Our findings demonstrate that combining macroscopic rheological measurements with the model allows for temperature-dependent characterization of polymer interaction parameters.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"246 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083783","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":"Multimodal Splitting and Reciprocating Transport of Droplets on a Reprogrammable Functional Surface","authors":"Ming Liu, Runan Chen, Jin Yuan, Cheng Chen, Zhilong Peng, Shaohua Chen","doi":"10.1021/acs.langmuir.4c04726","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04726","url":null,"abstract":"Droplet manipulations have important applications in many fields, especially droplet splitting and transport in aseptic operations or biochemical reagent analysis. However, droplet splitting or transport on existing functional surfaces is limited to predesigned microstructures or fixed patterns. It remains a challenge to realize reprogrammable surface microstructures for freely controllable droplet splitting and transport. In this study, a flexible technique for both the multimodal splitting and reciprocating transport of droplets on one surface is proposed. Such a surface is prepared with a facile fabrication method by premixing magnetic particles and softener into the polymer solvent matrix and immersing the solidified matrix in a lubricant. The movable wettability gradient is generated on the surface by an external magnetic field, which can act as an invisible “air knife” to split the droplet in multiple modes. The mechanism and critical conditions of droplet splitting are analyzed and revealed theoretically. Furthermore, the microstructural configurations and surface wettability can be reprogrammed by modulating the magnetic field strength and gradient. Accordingly, the splitting behavior of the droplet is transformed into the reciprocating transport behavior. The influencing factors of such behavior have also been analyzed. The reported reprogrammable manipulation of the droplet on one surface provides a versatile prototype for the actuation of droplets in microfluidic and biological analysis devices.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"5 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083784","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":"Novel Electrochemical Sensor Based on Cu-MOF/MWCNT-COOH for the Simultaneous Detection of Ascorbic Acid and Dopamine","authors":"Guoping Wang, Tian Tang, Ruichen Liu, Jingwen Li, Yi Xu, Sen Liao","doi":"10.1021/acs.langmuir.4c04455","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04455","url":null,"abstract":"By utilizing carboxylated multiwalled carbon nanotubes (MWCNT-COOH) to strengthen the interaction between the electrode and the analytes and improve the conductivity of the composite material and in conjunction with the superior catalytic properties of copper-based metal–organic framework (MOFs), a novel electrochemical sensor was fabricated from a Cu-MOF/MWCNT-COOH composite, specifically designed for the simultaneous and distinct detection of ascorbic acid (AA) and dopamine (DA). Electrochemical analyses were conducted on the innovative Cu-MOF/MWCNT-COOH electrode through both CV and DPV, revealing unique electrochemical behaviors for AA and DA. The sensor not only showed exceptional electrocatalytic properties but also distinguished itself by its broad dynamic response ranges, covering concentrations from 3 to 1800 μM for AA and from 2 to 180 μM for DA, with detection limits (S/N = 3) of 3.00 μM for AA and 0.32 μM for DA. Furthermore, this electrochemical detection platform exhibited robust reproducibility and selectivity. Examinations of serum samples yielded the recovery rates of AA and DA which were 101.9% and 102.1%, respectively, confirming the sensor’s capability to perform reliably under varied biological conditions. The findings confirm the sensor’s potential of the proposed method for the simultaneous, sensitive, and reliable detection of AA and DA. In conclusion, the electrochemical sensor has a promising potential for practical applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"6 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083786","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}