Pub Date : 2025-04-15DOI: 10.1021/acs.langmuir.5c00420
Tao Yao, Mingyu Zhang, Dongli Guo, Fen Ran
Nanofiltration membranes have the advantages of high flux and good selectivity, making them ideal materials for solving water resource pollution and scarcity; however, the mechanism of interface polymer membrane wrinkling induced by nanofillers is not clear, and the low flux of interface polymer membranes is a pressing issue for researchers. In this work, superhydrophilic l-histidine-modified nanoparticles are successfully synthesized and added to the interface polymerization process, where the nanoparticles also participate in the interface polymerization reaction, inducing interface polymerization. The formation of layered wrinkles on the membrane surface greatly increases the contact area of the membrane surface and enhances the hydrophilicity. The water contact angle on the membrane surface decreases from the original 51.85 to 28.72°. When the modifier-modified dopamine particles are added at a concentration of 0.1 wt %, the water permeance of the nanofiltration membrane reaches 145.57 L m–2 h–1 MPa–1, with a dye rejection rate of over 99% and high permeability to inorganic salt ions, confirming that the membrane can be used for efficient dye/salt separation. Furthermore, the stability of the membrane is improved, greatly enhancing its practical applicability.
{"title":"Nanofiltration Membrane via Organic Nanoparticle-Assisted Interface Polymerization for Efficient Dye/Salt Separation","authors":"Tao Yao, Mingyu Zhang, Dongli Guo, Fen Ran","doi":"10.1021/acs.langmuir.5c00420","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00420","url":null,"abstract":"Nanofiltration membranes have the advantages of high flux and good selectivity, making them ideal materials for solving water resource pollution and scarcity; however, the mechanism of interface polymer membrane wrinkling induced by nanofillers is not clear, and the low flux of interface polymer membranes is a pressing issue for researchers. In this work, superhydrophilic <span>l</span>-histidine-modified nanoparticles are successfully synthesized and added to the interface polymerization process, where the nanoparticles also participate in the interface polymerization reaction, inducing interface polymerization. The formation of layered wrinkles on the membrane surface greatly increases the contact area of the membrane surface and enhances the hydrophilicity. The water contact angle on the membrane surface decreases from the original 51.85 to 28.72°. When the modifier-modified dopamine particles are added at a concentration of 0.1 wt %, the water permeance of the nanofiltration membrane reaches 145.57 L m<sup>–2</sup> h<sup>–1</sup> MPa<sup>–1</sup>, with a dye rejection rate of over 99% and high permeability to inorganic salt ions, confirming that the membrane can be used for efficient dye/salt separation. Furthermore, the stability of the membrane is improved, greatly enhancing its practical applicability.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"60 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837196","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}
Two-dimensional (2D) materials have attracted significant attention owing to their exceptional electrical and optical properties. The high-quality monolayer 2D materials are usually fabricated by mechanical exfoliation from bulk single crystals using a scotch tape method, limiting the flake size and production yield. Extensive efforts have been made to increase the production yield and size by using an Au-assisted process, such as the modified mechanical exfoliation method. However, the wet-etching processes are inevitable in the scalable Au-assisted mechanical exfoliation method, which causes defect formation and unintentional contamination, leading to a quality decrease in the monolayer 2D material flakes. Here, we developed a Au-assisted all dry transfer method without any wet process for fabricating 2D materials and their van der Waals (vdW) heterostructures. The developed dry transfer technique using patterned Au substrates and h-BN on polymer stamps gives us a large area and designed shape of monolayer 2D materials and their vdW heterostructures with clean interfaces. It will be beneficial for building high-quality vdW heterostructures, allowing us to explore and develop more potential applications in electrical and optical devices based on monolayer 2D materials.
{"title":"All Dry Transfer Processes Utilizing Au Exfoliation for Predetermined Shapes of Transition Metal Dichalcogenide","authors":"Daiki Murase, Keisuke Shinokita, Yusai Wakafuji, Momoko Onodera, Tomoki Machida, Kenji Watanabe, Takashi Taniguchi, Jianfeng Bi, Zhou Zhou, Sihan Zhao, Kazunari Matsuda","doi":"10.1021/acs.langmuir.4c04629","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04629","url":null,"abstract":"Two-dimensional (2D) materials have attracted significant attention owing to their exceptional electrical and optical properties. The high-quality monolayer 2D materials are usually fabricated by mechanical exfoliation from bulk single crystals using a scotch tape method, limiting the flake size and production yield. Extensive efforts have been made to increase the production yield and size by using an Au-assisted process, such as the modified mechanical exfoliation method. However, the wet-etching processes are inevitable in the scalable Au-assisted mechanical exfoliation method, which causes defect formation and unintentional contamination, leading to a quality decrease in the monolayer 2D material flakes. Here, we developed a Au-assisted all dry transfer method without any wet process for fabricating 2D materials and their van der Waals (vdW) heterostructures. The developed dry transfer technique using patterned Au substrates and <i>h</i>-BN on polymer stamps gives us a large area and designed shape of monolayer 2D materials and their vdW heterostructures with clean interfaces. It will be beneficial for building high-quality vdW heterostructures, allowing us to explore and develop more potential applications in electrical and optical devices based on monolayer 2D materials.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837009","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}
Pub Date : 2025-04-15DOI: 10.1021/acs.langmuir.4c05130
Riyadi Priyo Darminto, Muhammad Arkan Nuruzzahran, Dzaki Ahmad Syaifullah, Hardika Ilhami, Nadhratun Naiim Mobarak, Hamad AlMohamadi, Fadjar Fathurrahman, Ni Luh Wulan Septiani, Adhitya Gandaryus Saputro
This study presents a comprehensive investigation of the oxygen evolution reaction (OER) activity on nickel phosphate (NiPO) surfaces doped with transition metals (Mn, Fe, Co, and Cu). By combining density functional theory calculations, the computational hydrogen electrode approximation, and microkinetic simulations, we demonstrate that transition metal doping significantly enhances OER performance compared to the pristine NiPO surface. The observed trends in overpotential values align with the oxygen adsorption energies on the doped surfaces, indicating a consistent improvement in catalytic activity. Despite the incorporation of different transition metals, the electronic profiles of surface nickel atoms remain largely unchanged, resulting in similar overpotential values at these sites. This suggests that the enhanced OER activity is primarily driven by the localized electronic states of the embedded transition metal dopants rather than changes in the nickel sites. Among the dopants studied, Fe and Mn exhibit the best OER performance, followed by Co and Cu.
{"title":"Influence of Transition Metal Doping on the Oxygen Evolution Reaction Activity of Nickel Phosphate Surface","authors":"Riyadi Priyo Darminto, Muhammad Arkan Nuruzzahran, Dzaki Ahmad Syaifullah, Hardika Ilhami, Nadhratun Naiim Mobarak, Hamad AlMohamadi, Fadjar Fathurrahman, Ni Luh Wulan Septiani, Adhitya Gandaryus Saputro","doi":"10.1021/acs.langmuir.4c05130","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05130","url":null,"abstract":"This study presents a comprehensive investigation of the oxygen evolution reaction (OER) activity on nickel phosphate (NiPO) surfaces doped with transition metals (Mn, Fe, Co, and Cu). By combining density functional theory calculations, the computational hydrogen electrode approximation, and microkinetic simulations, we demonstrate that transition metal doping significantly enhances OER performance compared to the pristine NiPO surface. The observed trends in overpotential values align with the oxygen adsorption energies on the doped surfaces, indicating a consistent improvement in catalytic activity. Despite the incorporation of different transition metals, the electronic profiles of surface nickel atoms remain largely unchanged, resulting in similar overpotential values at these sites. This suggests that the enhanced OER activity is primarily driven by the localized electronic states of the embedded transition metal dopants rather than changes in the nickel sites. Among the dopants studied, Fe and Mn exhibit the best OER performance, followed by Co and Cu.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"42 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832376","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}
Pub Date : 2025-04-15DOI: 10.1021/acs.langmuir.5c00763
Shuai Gong, Yu Ma, Hongyi Liu, Lei Shen
Protein–nanoparticle interactions are crucial in a diverse array of biotechnology and biomedical applications. Variations in nanoparticle sizes can adjust surface interactions with proteins and biomolecules, thereby influencing their conformation and functionality. To achieve precise control over the nanoparticle sizes corresponding to the dimensions of protein structural domains (∼nm) and establish the relationship between nanoparticle curvature and protein conformational changes, we conduct well-tempered metadynamics simulations to explore the secondary structure changes and thermodynamic characteristics of α-synuclein (αS), an intrinsically disordered protein (IDP), adsorbed onto silicon dioxide (SiO2) nanoparticles of varying sizes (diameter, d = 0.5–2.5 nm). The analysis of αS’s conformational landscapes and structural probabilities reveals that intermediate-sized SiO2 nanoparticles (d = 1.2–1.4 nm) effectively stabilize the native intrinsically disordered conformations of αS (with domain sizes of 1–2 nm). In contrast, excessively large or small SiO2 nanoparticles significantly enhance the likelihood of forming intramolecular β-sheet domains within αS chains, a process that is critical for subsequent aggregation of αS. This study is of significance to the development of nanoparticles that stabilize desired protein conformations, which may pave the way for in vivo penetration and distribution of nanoparticles as well as biomedicine therapeutic interventions aimed at targeting αS aggregation.
{"title":"Surface-Induced Conformational Changes of α-Synuclein on Silica Nanoparticles of Varying Sizes Corresponding to Protein Structural Domains: Insights from Enhanced Sampling MD Simulations","authors":"Shuai Gong, Yu Ma, Hongyi Liu, Lei Shen","doi":"10.1021/acs.langmuir.5c00763","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00763","url":null,"abstract":"Protein–nanoparticle interactions are crucial in a diverse array of biotechnology and biomedical applications. Variations in nanoparticle sizes can adjust surface interactions with proteins and biomolecules, thereby influencing their conformation and functionality. To achieve precise control over the nanoparticle sizes corresponding to the dimensions of protein structural domains (∼nm) and establish the relationship between nanoparticle curvature and protein conformational changes, we conduct well-tempered metadynamics simulations to explore the secondary structure changes and thermodynamic characteristics of α-synuclein (αS), an intrinsically disordered protein (IDP), adsorbed onto silicon dioxide (SiO<sub>2</sub>) nanoparticles of varying sizes (diameter, <i>d</i> = 0.5–2.5 nm). The analysis of αS’s conformational landscapes and structural probabilities reveals that intermediate-sized SiO<sub>2</sub> nanoparticles (<i>d</i> = 1.2–1.4 nm) effectively stabilize the native intrinsically disordered conformations of αS (with domain sizes of 1–2 nm). In contrast, excessively large or small SiO<sub>2</sub> nanoparticles significantly enhance the likelihood of forming intramolecular β-sheet domains within αS chains, a process that is critical for subsequent aggregation of αS. This study is of significance to the development of nanoparticles that stabilize desired protein conformations, which may pave the way for in vivo penetration and distribution of nanoparticles as well as biomedicine therapeutic interventions aimed at targeting αS aggregation.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"120 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832380","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.5c00633
Chinmaya Kumar Patel, Abhradip Mallik, Deb Kumar Rath, Rajesh Kumar, Tushar Kanti Mukherjee
Liquid-to-solid-like phase transition (LSPT) of disordered proteins via metastable liquid-like droplets is a well-documented phenomenon in biology and is linked to many pathological conditions including neurodegenerative diseases. However, very less is known about the early microscopic events and transient intermediates involved in the irreversible protein aggregation of functional globular proteins. Herein, using a range of microscopic and spectroscopic techniques, we show that the LSPT of a functional globular protein, human serum albumin (HSA), is exclusively driven by spontaneous coalescence of liquid-like droplets involving various transient intermediates in a temporal manner. We show that interdroplet communication via coalescence is essential for both initial aggregation and growth of amorphous aggregates within individual droplets, which subsequently transform to amyloid-like fibrils. Immobilized droplets neither show any nucleation nor any growth upon aging. Moreover, we found that the exchange of materials with the dilute dispersed phase has negligible influence on the LSPT of HSA. Our findings reveal that interfacial properties effectively modulate the feasibility and kinetics of LSPT of HSA via ligand binding, suggesting a possible regulatory mechanism that cells utilize to control the dynamics of LSPT. Furthermore, using a dynamic heterogeneous droplet assembly of two functional proteins, HSA and human serum transferrin (Tf), we show an intriguing phenomenon within the fused droplets where both liquid-like and solid-like phases coexist within the same droplet, which eventually transform to a mixed fibrillar assembly. These microscopic insights not only highlight the importance of interdroplet interactions behind the LSPT of biomolecules but also showcase its adverse effect on the structure and function of other functional proteins in a crowded and heterogeneous protein assembly.
{"title":"Coalescence-Driven Local Crowding Promotes Liquid-to-Solid-Like Phase Transition in a Homogeneous and Heterogeneous Droplet Assembly: Regulatory Role of Ligands","authors":"Chinmaya Kumar Patel, Abhradip Mallik, Deb Kumar Rath, Rajesh Kumar, Tushar Kanti Mukherjee","doi":"10.1021/acs.langmuir.5c00633","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00633","url":null,"abstract":"Liquid-to-solid-like phase transition (LSPT) of disordered proteins via metastable liquid-like droplets is a well-documented phenomenon in biology and is linked to many pathological conditions including neurodegenerative diseases. However, very less is known about the early microscopic events and transient intermediates involved in the irreversible protein aggregation of functional globular proteins. Herein, using a range of microscopic and spectroscopic techniques, we show that the LSPT of a functional globular protein, human serum albumin (HSA), is exclusively driven by spontaneous coalescence of liquid-like droplets involving various transient intermediates in a temporal manner. We show that interdroplet communication via coalescence is essential for both initial aggregation and growth of amorphous aggregates within individual droplets, which subsequently transform to amyloid-like fibrils. Immobilized droplets neither show any nucleation nor any growth upon aging. Moreover, we found that the exchange of materials with the dilute dispersed phase has negligible influence on the LSPT of HSA. Our findings reveal that interfacial properties effectively modulate the feasibility and kinetics of LSPT of HSA via ligand binding, suggesting a possible regulatory mechanism that cells utilize to control the dynamics of LSPT. Furthermore, using a dynamic heterogeneous droplet assembly of two functional proteins, HSA and human serum transferrin (Tf), we show an intriguing phenomenon within the fused droplets where both liquid-like and solid-like phases coexist within the same droplet, which eventually transform to a mixed fibrillar assembly. These microscopic insights not only highlight the importance of interdroplet interactions behind the LSPT of biomolecules but also showcase its adverse effect on the structure and function of other functional proteins in a crowded and heterogeneous protein assembly.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"60 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832382","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.5c00186
Ling Lin, Shuang Yuan, Huahui Chen, Peng Xu, Tao Zhu, Long Li, Jiaojing Shao
The cobalt-free, high-voltage spinel-type cathode LiNi0.5Mn1.5O4 (LNMO) exhibits high energy and power densities, rendering it a promising candidate for incorporation into next-generation lithium-ion batteries (LIBs). However, its high operating voltage of 4.7 V can lead to electrolyte decomposition, causing structural damage. In addition, the irreversible loss of active lithium in the early cycles reduces capacity performance, hindering its commercial application. To take full advantage of the catalytic effect of LNMO and the prelithiation of sacrificial salt, this work involved blending sacrificial salts (Li2C2O4, Li2CO3, and CH3COOLi) with LNMO to form prelithiated electrodes (LNMO-Sac) and investigating the influence of different sacrificial salts on the performance of LIBs. The results demonstrate that LNMO could efficiently catalyze the decomposition of sacrificial salts and promote the formation of a more stable electrode–electrolyte interface after cycling to mitigate structure destruction of electrodes caused by electrolyte decomposition. Compared with other sacrificial salts, Li2C2O4 provided a highly efficient supplement of active lithium and improved the electrochemical performance of the battery. Thus, LNMO-Li2C2O4 achieved an excellent discharge capacity of 137.9 mAh g–1 at 1C, and capacity retention of 85.9% after 500 cycles, superior to that of LNMO without prelithiation. Moreover, the LNMO-LO/Gr full cell presented an initial capacity of 117.9 mAh g–1 and retained 79.4 mAh g–1 after 300 cycles. This work demonstrates the feasibility of a sacrificial salt as a lithium replenishment strategy for LNMO in practical applications.
{"title":"Sacrificial Prelithiation Using Different Lithium Salt-Coated LNMO Cathodes for Stabilizing the Electrode Structure and Enhancing Battery Performance","authors":"Ling Lin, Shuang Yuan, Huahui Chen, Peng Xu, Tao Zhu, Long Li, Jiaojing Shao","doi":"10.1021/acs.langmuir.5c00186","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00186","url":null,"abstract":"The cobalt-free, high-voltage spinel-type cathode LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub> (LNMO) exhibits high energy and power densities, rendering it a promising candidate for incorporation into next-generation lithium-ion batteries (LIBs). However, its high operating voltage of 4.7 V can lead to electrolyte decomposition, causing structural damage. In addition, the irreversible loss of active lithium in the early cycles reduces capacity performance, hindering its commercial application. To take full advantage of the catalytic effect of LNMO and the prelithiation of sacrificial salt, this work involved blending sacrificial salts (Li<sub>2</sub>C<sub>2</sub>O<sub>4</sub>, Li<sub>2</sub>CO<sub>3</sub>, and CH<sub>3</sub>COOLi) with LNMO to form prelithiated electrodes (LNMO-Sac) and investigating the influence of different sacrificial salts on the performance of LIBs. The results demonstrate that LNMO could efficiently catalyze the decomposition of sacrificial salts and promote the formation of a more stable electrode–electrolyte interface after cycling to mitigate structure destruction of electrodes caused by electrolyte decomposition. Compared with other sacrificial salts, Li<sub>2</sub>C<sub>2</sub>O<sub>4</sub> provided a highly efficient supplement of active lithium and improved the electrochemical performance of the battery. Thus, LNMO-Li<sub>2</sub>C<sub>2</sub>O<sub>4</sub> achieved an excellent discharge capacity of 137.9 mAh g<sup>–1</sup> at 1C, and capacity retention of 85.9% after 500 cycles, superior to that of LNMO without prelithiation. Moreover, the LNMO-LO/Gr full cell presented an initial capacity of 117.9 mAh g<sup>–1</sup> and retained 79.4 mAh g<sup>–1</sup> after 300 cycles. This work demonstrates the feasibility of a sacrificial salt as a lithium replenishment strategy for LNMO in practical applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"108 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832142","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.5c00043
L. E. Helseth
Charge transfer due to a water–air contact line moving over a fluoropolymer hydrophobic surface is investigated for an aqueous solution containing surface-active molecules. It is found that anionic (SDS) and neutral (Triton X-100) surfactants exhibit a two-stage charge transfer reduction with concentration. At low concentrations, a layer of surfactant molecules accumulates near the hydrophobic surface and partially quenches the charge transfer. Surprisingly, after this first stage, the charge transfer remains nearly constant or weakly increasing, while the concentration of surfactants increases several orders of magnitude. Eventually, for large enough concentrations, the charge transfer continues to decrease, eventually resulting in almost zero charge transfer before reaching the critical micelle concentration. For the cationic surfactant (CTAB), the behavior is entirely different and a single quenching mechanism can explain the observed reduction in charge transfer due to positively charged surface-active molecules forming a layer that electrostatically screens the water-induced negative charge residing on the hydrophobic interface. A similar behavior is observed for poly(vinyl alcohol), which is attributed to its known and strong interaction with the hydrophobic surface used in this study.
{"title":"Influence of Surface-Active Molecules in Solution on Charge Transfer Due to a Water–Air Contact Line Moving over a Hydrophobic Surface","authors":"L. E. Helseth","doi":"10.1021/acs.langmuir.5c00043","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00043","url":null,"abstract":"Charge transfer due to a water–air contact line moving over a fluoropolymer hydrophobic surface is investigated for an aqueous solution containing surface-active molecules. It is found that anionic (SDS) and neutral (Triton X-100) surfactants exhibit a two-stage charge transfer reduction with concentration. At low concentrations, a layer of surfactant molecules accumulates near the hydrophobic surface and partially quenches the charge transfer. Surprisingly, after this first stage, the charge transfer remains nearly constant or weakly increasing, while the concentration of surfactants increases several orders of magnitude. Eventually, for large enough concentrations, the charge transfer continues to decrease, eventually resulting in almost zero charge transfer before reaching the critical micelle concentration. For the cationic surfactant (CTAB), the behavior is entirely different and a single quenching mechanism can explain the observed reduction in charge transfer due to positively charged surface-active molecules forming a layer that electrostatically screens the water-induced negative charge residing on the hydrophobic interface. A similar behavior is observed for poly(vinyl alcohol), which is attributed to its known and strong interaction with the hydrophobic surface used in this study.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"5 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827345","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.5c00852
Cathie Ventalon, Oksana Kirichuk, Yotam Navon, Yan Chastagnier, Laurent Heux, Ralf P. Richter, Lionel Bureau, Delphine Débarre
Reflection interference contrast microscopy (RICM, also known as interference reflection microscopy) and related techniques have become of wide interest to the biophysical, soft matter, and biochemistry communities owing to their exquisite sensitivity for characterizing thin films or individual nanoscopic objects adsorbed onto surfaces, or for monitoring cell–substrate interactions. Over the recent years, striking progress has been made to improve the sensitivity and the quantitative analysis of RICM. Its use in more complex environments, with spurious reflections stemming from a variety of structures in the sample, remains however challenging. In this paper, we demonstrate two optical sectioning methods that effectively reduce such background and can be readily implemented in a conventional RICM setup: line confocal detection and structured illumination microscopy. We characterize experimentally the benefits to image quality and demonstrate the use of the methods for quantitative imaging of complex biological and biomimetic samples: cellular membranes, thin organic films, biofunctional surfaces. We then discuss the benefits of each method and provide guidelines to arbitrate between sectioning and signal-to-noise ratio. Finally, we provide a detailed description of our experimental setup and a home-written image acquisition and processing software that should allow the interested reader to duplicate such a setup on a home-built or commercial microscope.
{"title":"Optical Sectioning for Reflection Interference Microscopy: Quantitative Imaging at Soft Interfaces","authors":"Cathie Ventalon, Oksana Kirichuk, Yotam Navon, Yan Chastagnier, Laurent Heux, Ralf P. Richter, Lionel Bureau, Delphine Débarre","doi":"10.1021/acs.langmuir.5c00852","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00852","url":null,"abstract":"Reflection interference contrast microscopy (RICM, also known as interference reflection microscopy) and related techniques have become of wide interest to the biophysical, soft matter, and biochemistry communities owing to their exquisite sensitivity for characterizing thin films or individual nanoscopic objects adsorbed onto surfaces, or for monitoring cell–substrate interactions. Over the recent years, striking progress has been made to improve the sensitivity and the quantitative analysis of RICM. Its use in more complex environments, with spurious reflections stemming from a variety of structures in the sample, remains however challenging. In this paper, we demonstrate two optical sectioning methods that effectively reduce such background and can be readily implemented in a conventional RICM setup: line confocal detection and structured illumination microscopy. We characterize experimentally the benefits to image quality and demonstrate the use of the methods for quantitative imaging of complex biological and biomimetic samples: cellular membranes, thin organic films, biofunctional surfaces. We then discuss the benefits of each method and provide guidelines to arbitrate between sectioning and signal-to-noise ratio. Finally, we provide a detailed description of our experimental setup and a home-written image acquisition and processing software that should allow the interested reader to duplicate such a setup on a home-built or commercial microscope.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"120 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827347","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.4c03767
Bibek Kumar, Sanghamitro Chatterjee, Amit Agrawal, Rajneesh Bhardwaj
We study the combined effect of varying droplet volume and inclination angles on the desiccation patterns left behind evaporating sessile droplets of human blood. We systematically varied the droplet volume in a range of [1–10 μL] and inclination angles between [0–70°]. Microstructural characterization of the deposits was performed using optical microscopy and surface profilometry. On a horizontal surface, typical deposits of toroidal shape with cracks oriented in radial and azimuthal directions were observed. With an increase in the droplet volume and inclination, the interplay between the gravitational and surface tension effects leads to an asymmetric liquid–vapor interface shape, resulting in a differential evaporative mass flux pattern across the interface. Subsequently, we observe elongation of the overall desiccation patterns along with asymmetric mass deposits between the advancing and receding fronts. As a consequence, the crack morphology on the two fronts exhibits pronounced differences. The distinct regimes of asymmetric mass deposits and crack morphology were quantitatively examined as a characteristic of varying droplet volume and inclinations, parametrized in terms of the mean radial crack spacing and width. These findings are qualitatively analyzed by a first-order theoretical model that is based on the energy conservation principle incorporating the release of mechanical stress energy by contraction of the deposit at the last stage of the desiccation process and the consumed surface energy upon formation of the new surfaces during crack evolution.
{"title":"Asymmetric Deposits and Crack Formation during Desiccation of a Blood Droplet on an Inclined Surface","authors":"Bibek Kumar, Sanghamitro Chatterjee, Amit Agrawal, Rajneesh Bhardwaj","doi":"10.1021/acs.langmuir.4c03767","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03767","url":null,"abstract":"We study the combined effect of varying droplet volume and inclination angles on the desiccation patterns left behind evaporating sessile droplets of human blood. We systematically varied the droplet volume in a range of [1–10 μL] and inclination angles between [0–70°]. Microstructural characterization of the deposits was performed using optical microscopy and surface profilometry. On a horizontal surface, typical deposits of toroidal shape with cracks oriented in radial and azimuthal directions were observed. With an increase in the droplet volume and inclination, the interplay between the gravitational and surface tension effects leads to an asymmetric liquid–vapor interface shape, resulting in a differential evaporative mass flux pattern across the interface. Subsequently, we observe elongation of the overall desiccation patterns along with asymmetric mass deposits between the advancing and receding fronts. As a consequence, the crack morphology on the two fronts exhibits pronounced differences. The distinct regimes of asymmetric mass deposits and crack morphology were quantitatively examined as a characteristic of varying droplet volume and inclinations, parametrized in terms of the mean radial crack spacing and width. These findings are qualitatively analyzed by a first-order theoretical model that is based on the energy conservation principle incorporating the release of mechanical stress energy by contraction of the deposit at the last stage of the desiccation process and the consumed surface energy upon formation of the new surfaces during crack evolution.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"40 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832379","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}
Pub Date : 2025-04-14DOI: 10.1021/acs.langmuir.5c0004310.1021/acs.langmuir.5c00043
L. E. Helseth*,
Charge transfer due to a water–air contact line moving over a fluoropolymer hydrophobic surface is investigated for an aqueous solution containing surface-active molecules. It is found that anionic (SDS) and neutral (Triton X-100) surfactants exhibit a two-stage charge transfer reduction with concentration. At low concentrations, a layer of surfactant molecules accumulates near the hydrophobic surface and partially quenches the charge transfer. Surprisingly, after this first stage, the charge transfer remains nearly constant or weakly increasing, while the concentration of surfactants increases several orders of magnitude. Eventually, for large enough concentrations, the charge transfer continues to decrease, eventually resulting in almost zero charge transfer before reaching the critical micelle concentration. For the cationic surfactant (CTAB), the behavior is entirely different and a single quenching mechanism can explain the observed reduction in charge transfer due to positively charged surface-active molecules forming a layer that electrostatically screens the water-induced negative charge residing on the hydrophobic interface. A similar behavior is observed for poly(vinyl alcohol), which is attributed to its known and strong interaction with the hydrophobic surface used in this study.
{"title":"Influence of Surface-Active Molecules in Solution on Charge Transfer Due to a Water–Air Contact Line Moving over a Hydrophobic Surface","authors":"L. E. Helseth*, ","doi":"10.1021/acs.langmuir.5c0004310.1021/acs.langmuir.5c00043","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00043https://doi.org/10.1021/acs.langmuir.5c00043","url":null,"abstract":"<p >Charge transfer due to a water–air contact line moving over a fluoropolymer hydrophobic surface is investigated for an aqueous solution containing surface-active molecules. It is found that anionic (SDS) and neutral (Triton X-100) surfactants exhibit a two-stage charge transfer reduction with concentration. At low concentrations, a layer of surfactant molecules accumulates near the hydrophobic surface and partially quenches the charge transfer. Surprisingly, after this first stage, the charge transfer remains nearly constant or weakly increasing, while the concentration of surfactants increases several orders of magnitude. Eventually, for large enough concentrations, the charge transfer continues to decrease, eventually resulting in almost zero charge transfer before reaching the critical micelle concentration. For the cationic surfactant (CTAB), the behavior is entirely different and a single quenching mechanism can explain the observed reduction in charge transfer due to positively charged surface-active molecules forming a layer that electrostatically screens the water-induced negative charge residing on the hydrophobic interface. A similar behavior is observed for poly(vinyl alcohol), which is attributed to its known and strong interaction with the hydrophobic surface used in this study.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"41 15","pages":"9716–9728 9716–9728"},"PeriodicalIF":3.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.langmuir.5c00043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：