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Azad R, Sharma T, Martin D, Daschakraborty S, Raj R. Unraveling the Surface Activity of Ethanol-Water Mixtures through Experiments and Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:17577-17589. [PMID: 39109962 DOI: 10.1021/acs.langmuir.4c01825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
Ethanol's complete miscibility in water makes it a widely used solvent in various applications, such as organic compound synthesis, paint manufacture, chromatography, and cosmetics preservation. Studies suggest that ethanol's concentration at interfaces can be higher than in the bulk due to its amphiphilic nature, especially at lower concentrations, making it a surface-active agent. Accordingly, ethanol plays a crucial role in controlling the emulsion stability, foam formation, heat transfer, and coating adhesion. However, the precise concentration ranges up to which ethanol's surface activity dominates its interfacial properties, and the underlying molecular mechanism is not fully understood in the literature. In this context, our foamability experiments, coupled with film stability experiments conducted via ethanol drop impact on varying concentration ethanol-water mixture pools, indicate that the surface-active nature of ethanol is observed up to a maximum of 10% molar ethanol concentration in water. We next employ all-atom molecular dynamics simulations to reveal that the surface tension and other interfacial properties are most significantly affected only up to the molar concentration in the range of 0-10% of ethanol in water. This observation is further supported by free energy analyses, indicating that the stabilization free energy of an ethanol molecule at the interface becomes comparable to that in the bulk region beyond this concentration range. The transition from surface-active to a behavior resembling a homogeneous solution occurs when the molar concentration of ethanol in water exceeds 10%. This transition is attributed to distinctive alterations in the number and strength of ethanol-water hydrogen bonds. These findings provide valuable insights into the interfacial molecular structure, which can be suitably exploited to modulate interfacial properties and dynamic behavior in a wide array of industrial and scientific applications.
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Affiliation(s)
- Rajnish Azad
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Patna, Bihar 801103, India
| | - Tonmoy Sharma
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Patna, Bihar 801103, India
| | - Dave Martin
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Patna, Bihar 801103, India
| | | | - Rishi Raj
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Patna, Bihar 801103, India
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2
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Ozon M, Tumashevich K, Lin JJ, Prisle NL. Inversion model for extracting chemically resolved depth profiles across liquid interfaces of various configurations from XPS data: PROPHESY. JOURNAL OF SYNCHROTRON RADIATION 2023; 30:941-961. [PMID: 37610342 PMCID: PMC10481271 DOI: 10.1107/s1600577523006124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/12/2023] [Indexed: 08/24/2023]
Abstract
PROPHESY, a technique for the reconstruction of surface-depth profiles from X-ray photoelectron spectroscopy data, is introduced. The inversion methodology is based on a Bayesian framework and primal-dual convex optimization. The acquisition model is developed for several geometries representing different sample types: plane (bulk sample), cylinder (liquid microjet) and sphere (droplet). The methodology is tested and characterized with respect to simulated data as a proof of concept. Possible limitations of the method due to uncertainty in the attenuation length of the photo-emitted electron are illustrated.
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Affiliation(s)
- Matthew Ozon
- Center for Atmospheric Research, University of Oulu, PO Box 4500, Finland
| | | | - Jack J. Lin
- Center for Atmospheric Research, University of Oulu, PO Box 4500, Finland
| | - Nønne L. Prisle
- Center for Atmospheric Research, University of Oulu, PO Box 4500, Finland
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3
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Yu X, Chiang KY, Yu CC, Bonn M, Nagata Y. On the Fresnel factor correction of sum-frequency generation spectra of interfacial water. J Chem Phys 2023; 158:044701. [PMID: 36725499 DOI: 10.1063/5.0133428] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Insights into the microscopic structure of aqueous interfaces are essential for understanding the chemical and physical processes on the water surface, including chemical synthesis, atmospheric chemistry, and events in biomolecular systems. These aqueous interfaces have been probed by heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. To obtain the molecular response from the measured HD-SFG spectra, one needs to correct the measured ssp spectra for local electromagnetic field effects at the interface due to a spatially varying dielectric function. This so-called Fresnel factor correction can change the inferred response substantially, and different ways of performing this correction lead to different conclusions about the interfacial water response. Here, we compare the simulated and experimental spectra at the air/water interface. We use three previously developed models to compare the experiment with theory: an advanced approach taking into account the detailed inhomogeneous interfacial dielectric profile and the Lorentz and slab models to approximate the interfacial dielectric function. Using the advanced model, we obtain an excellent quantitative agreement between theory and experiment, in both spectral shape and amplitude. Remarkably, we find that for the Fresnel factor correction of the ssp spectra, the Lorentz model for the interfacial dielectric function is equally accurate in the hydrogen (H)-bonded region of the response, while the slab model underestimates this response significantly. The Lorentz model, thus, provides a straightforward method to obtain the molecular response from the measured spectra of aqueous interfaces in the H-bonded region.
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Affiliation(s)
- Xiaoqing Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Kuo-Yang Chiang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Chun-Chieh Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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4
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Das B, Chandra A. Vibrational Sum Frequency Generation Spectra of Water-Vapor Interfaces Covered by Alcohols: Effects of Surface Coverage and Coupling between Oscillators. Chemphyschem 2022; 24:e202200604. [PMID: 36537178 DOI: 10.1002/cphc.202200604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
The present study deals with the effects of varying coverage of water surface by alcohols on the vibrational sum frequency generation (VSFG) spectrum of interfacial water. We have considered two different alcohols: Tertiary butyl alcohol (TBA) whose alkyl part is fully branched and stearyl alcohol (STA) which has a long linear alkyl chain with larger hydrophobic surface area than that of TBA. With increase of the alcohol concentration, the hydrogen bonded OH stretch region of the VSFG spectrum is found to change following a regular trend for the STA-water system, whereas non-monotonic variation of the VSFG spectrum is observed for the TBA-water system which can be correlated with the presence of very different interactions of TBA molecules at different concentrations. On increasing the concentration of TBA, the hydrophobic groups get more tilted towards the water phase and significant hydrophobic interactions are introduced at higher concentrations. Whereas, for STA, there is a gradual increase in the hydrophilic interaction. Because of stacking interactions between the long chain alkyl groups, the hydrophobic parts stay outward from the water phase at higher concentrations and a regular change in the VSFG spectrum is observed. We have also presented a computationally efficient scheme to calculate the VSFG spectrum of interfacial systems for coupled oscillators which is expected to be beneficial for the treatment of coupling where the interfacial system size is inherently large.
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Affiliation(s)
- Banshi Das
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India, 208016
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5
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Ågren H, Björneholm O, Öhrwall G, Carravetta V, de Brito AN. Ethanol in Aqueous Solution Studied by Microjet Photoelectron Spectroscopy and Theory. Acc Chem Res 2022; 55:3080-3087. [PMID: 36251058 DOI: 10.1021/acs.accounts.2c00471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
By combining results and analysis from cylindrical microjet photoelectron spectroscopy (cMJ-PES) and theoretical simulations, we unravel the microscopic properties of ethanol-water solutions with respect to structure and intermolecular bonding patterns following the full concentration scale from 0 to 100% ethanol content. In particular, we highlight the salient differences between bulk and surface. Like for the pure water and alcohol constituents, alcohol-water mixtures have attracted much interest in applications of X-ray spectroscopies owing to their potential of combining electronic and geometric structure probing. The water mixtures of the two simplest alcohols, methanol and ethanol, have generated particular attention due to their delicate hydrogen bonding networks that underlie their structural and thermodynamic properties. Macroscopically ethanol-water seems to mix very well, however microscopically this is not true. The aberrant thermodynamics of water-alcohol mixtures have been suggested to be caused by energy differences of hydrogen bonding between water-water, alcohol-alcohol and alcohol-water molecules. These networks may perturb the local character of the interaction between X-rays and matter, calling for analysis that go beyond the normally applied local selection and building block rules and that can combine the effects of light-matter, intra- and intermolecular interactions. However, despite decades of ongoing research there are still controversies of the precise nature of hydrogen bonding networks that underlie the mixing of these simple molecules. Our combined analysis indicates that at low concentration ethanol molecules form a film at the surface since ethanol at the surface can expose its hydrophobic part to the vacuum retaining its two (or three) possible hydrogen bonds, while water at the surface cannot retain all its four possible hydrogen bonds. Thus, ethanol at the surface becomes energetically favorable. Ethanol molecules show a tilting angle variation of the C-C axis with respect to the surface normal as large as 60° at very low concentration. In bulk, around ca. ten %, the ethanol oxygen atoms tend to make a third acceptor hydrogen bond to water molecules. At ca. 20 %, there is a U-shaped change in the CH3 to CH2OH binding energy (BE) shift indicating the presence of ring-like agglomerates called clathrate structures. At the surface, between 5 and 25%, ethanol forms a closely packed layer with the smallest C-C tilting angle variation down to ∼20°. Above 25% and below the azeotrope at the surface, ethanol shows an increase in the tilting angle variation, while at very high ethanol concentrations water tends to move to the surface so giving a microscopic explanation of the azeotrope effect. This migration is connected to the presence of longer (shorter) ethanol chains in the bulk (surface). A brief comparison with discussions and predictions from other spectroscopic techniques is also given. We emphasize the execution of an integrated approach that combines molecular structural dynamics with quantum predictions of the core electronic chemical shift, so establishing a protocol with considerable interpretative as well as predictive power for cMJ-PES measurements. We believe that this protocol can valorize cMJ-PES for studies of properties of other alcohol mixtures as well as of binary solutions in general.
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Affiliation(s)
- Hans Ågren
- Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Olle Björneholm
- Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Gunnar Öhrwall
- MAX IV Laboratory, Lund University, Box 118, SE-22100 Lund, Sweden
| | - Vincenzo Carravetta
- CNR-IPCF, Institute of Chemical Physical Processes, via G.Moruzzi 1, I-56124 Pisa, Italy
| | - Arnaldo Naves de Brito
- Department of Applied Physics, Institute of Physics "Gleb Wataghin", Campinas University, CEP 13083859 Campinas SP, Brazil
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6
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Carravetta V, Gomes AHDA, Marinho RDRT, Öhrwall G, Ågren H, Björneholm O, de Brito AN. An atomistic explanation of the ethanol-water azeotrope. Phys Chem Chem Phys 2022; 24:26037-26045. [PMID: 36268753 DOI: 10.1039/d2cp03145k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ethanol and water form an azeotropic mixture at an ethanol molecular percentage of ∼91% (∼96% by volume), which prohibits ethanol from being further purified via distillation. Aqueous solutions at different concentrations in ethanol have been studied both experimentally and theoretically. We performed cylindrical micro-jet photoelectron spectroscopy, excited by synchrotron radiation, 70 eV above C1s ionization threshold, providing optimal atomic-scale surface-probing. Large model systems have been employed to simulate, by molecular dynamics, slabs of the aqueous solutions and obtain an atomistic description of both bulk and surface regions. We show how the azeotropic behaviour results from an unexpected concentration-dependence of the surface composition. While ethanol strongly dominates the surface and water is almost completely depleted from the surface for most mixing ratios, the different intermolecular bonding patterns of the two components cause water to penetrate to the surface region at high ethanol concentrations. The addition of surface water increases its relative vapour pressure, giving rise to the azeotropic behaviour.
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Affiliation(s)
- Vincenzo Carravetta
- CNR-IPCF, Institute of Chemical and Physical Processes, via G. Moruzzi 1, I-56124 Pisa, Italy.
| | - Anderson Herbert de Abreu Gomes
- Dept. of Applied Physics, Institute of Physics "Gleb Wataghin", Campinas University, CEP: 13083-859 Campinas, SP, Brazil. .,Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research on Energy and Materials (CNPEM), PO Box 6192, 13083-970, Campinas, SP, Brazil
| | - Ricardo Dos Reis Teixeira Marinho
- Institute of Physics, Federal University of Bahia, 40.170-115, Salvador, BA, Brazil.,Institute of Physics, Brasilia University (UnB), 70.919-970, Brasília, Brazil
| | - Gunnar Öhrwall
- MAX IV Laboratory, Lund University, Box 118, SE-22100 Lund, Sweden
| | - Hans Ågren
- Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Olle Björneholm
- Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Arnaldo Naves de Brito
- Dept. of Applied Physics, Institute of Physics "Gleb Wataghin", Campinas University, CEP: 13083-859 Campinas, SP, Brazil.
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7
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Pan A, Phani Kumar BV, Mati SS, Mal A, Prameela GK, Aswal VK, Moulik SP. Condition dependent self-aggregation behavior of aerosol-OT in mixed water-alcohol media: Physicochemical investigation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Yu CC, Imoto S, Seki T, Chiang KY, Sun S, Bonn M, Nagata Y. Accurate molecular orientation at interfaces determined by multimode polarization-dependent heterodyne-detected sum-frequency generation spectroscopy via multidimensional orientational distribution function. J Chem Phys 2022; 156:094703. [DOI: 10.1063/5.0081209] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many essential processes occur at soft interfaces, from chemical reactions on aqueous aerosols in the atmosphere to biochemical recognition and binding at the surface of cell membranes. The spatial arrangement of molecules specifically at these interfaces is crucial for many of such processes. The accurate determination of the interfacial molecular orientation has been challenging due to the low number of molecules at interfaces and the ambiguity of their orientational distribution. Here, we combine phase- and polarization-resolved sum-frequency generation (SFG) spectroscopy to obtain the molecular orientation at the interface. We extend an exponentially decaying orientational distribution to multiple dimensions, which, in conjunction with multiple SFG datasets obtained from the different vibrational modes, allows us to determine the molecular orientation. We apply this new approach to formic acid molecules at the air–water interface. The inferred orientation of formic acid agrees very well with ab initio molecular dynamics data. The phase-resolved SFG multimode analysis scheme using the multidimensional orientational distribution thus provides a universal approach for obtaining the interfacial molecular orientation.
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Affiliation(s)
- Chun-Chieh Yu
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Sho Imoto
- Analysis Technology Center, Fujifilm R&D, 210 Nakanuma, Minamiashigara, Kanagawa 250-0123, Japan
| | - Takakazu Seki
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Kuo-Yang Chiang
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Shumei Sun
- Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, 100875 Beijing, China
| | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yuki Nagata
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
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9
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Tran HP, Delance L, Passade-Boupat N, Verneuil E, Lequeux F, Talini L. Foaming of Binary Mixtures: Link with the Nonlinear Behavior of Surface Tension in Asymmetric Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:13444-13451. [PMID: 34726919 DOI: 10.1021/acs.langmuir.1c02198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The lifetimes of single bubbles or foams that are formed in mixtures of liquids can be several orders of magnitude larger than the ones formed in pure liquids. We recently demonstrated that this enhanced stability results from differences between bulk and interfacial concentrations in the mixture, which induce a thickness dependence of the surface tension in liquid films, and thus a stabilizing Marangoni effect. Concentration differences may be associated with nonlinear variations of surface tension with composition and we further investigate their link with foamability of binary mixtures. We show that, for asymmetric binary mixtures, that is, made of molecules of very different sizes, strong nonlinearities in surface tension can be measured, that are associated with large foam lifetimes. When the molecules that occupy the largest surface areas have the smallest surface tension, the surface tension of the mixture varies sublinearly with composition, reflecting an enrichment in this species at the interface with air, as classically reported in the literature. In contrast, when they exhibit the largest surface tension, superlinear variations of surface tension are observed, despite a similar enrichment. We discuss these variations in light of a simple thermodynamic model for ideal mixtures and we demonstrate why foam stability is enhanced for both sublinear and superlinear surface tension variations, thus, shedding new light on foamability without added surfactants.
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Affiliation(s)
- H P Tran
- CNRS, Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL Research University, Sorbonne Université, 75005 Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI, 10 rue Vauquelin, 75005 Paris, France
- Bâtiment CHEMSTARTUP, Route Départementale 817, 64170 Lacq, France
| | - L Delance
- CNRS, Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL Research University, Sorbonne Université, 75005 Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI, 10 rue Vauquelin, 75005 Paris, France
- Bâtiment CHEMSTARTUP, Route Départementale 817, 64170 Lacq, France
| | - N Passade-Boupat
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI, 10 rue Vauquelin, 75005 Paris, France
- Bâtiment CHEMSTARTUP, Route Départementale 817, 64170 Lacq, France
- Total S.A. 64170 Lacq, France
| | - E Verneuil
- CNRS, Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL Research University, Sorbonne Université, 75005 Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI, 10 rue Vauquelin, 75005 Paris, France
- Bâtiment CHEMSTARTUP, Route Départementale 817, 64170 Lacq, France
| | - F Lequeux
- CNRS, Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL Research University, Sorbonne Université, 75005 Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI, 10 rue Vauquelin, 75005 Paris, France
- Bâtiment CHEMSTARTUP, Route Départementale 817, 64170 Lacq, France
| | - L Talini
- CNRS, Surface du Verre et Interfaces, Saint-Gobain, 93300 Aubervilliers, France
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Yu X, Seki T, Yu CC, Zhong K, Sun S, Okuno M, Backus EHG, Hunger J, Bonn M, Nagata Y. Interfacial Water Structure of Binary Liquid Mixtures Reflects Nonideal Behavior. J Phys Chem B 2021; 125:10639-10646. [PMID: 34503330 PMCID: PMC8474108 DOI: 10.1021/acs.jpcb.1c06001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/21/2021] [Indexed: 11/28/2022]
Abstract
The evaporation of molecules from water-organic solute binary mixtures is key for both atmospheric and industrial processes such as aerosol formation and distillation. Deviations from ideal evaporation energetics can be assigned to intermolecular interactions in solution, yet evaporation occurs from the interface, and the poorly understood interfacial, rather than the bulk, structure of binary mixtures affects evaporation kinetics. Here we determine the interfacial structure of nonideal binary mixtures of water with methanol, ethanol, and formic acid, by combining surface-specific vibrational spectroscopy with molecular dynamics simulations. We find that the free, dangling OH groups at the interfaces of these differently behaving nonideal mixtures are essentially indistinguishable. In contrast, the ordering of hydrogen-bonded interfacial water molecules differs substantially at these three interfaces. Specifically, the interfacial water molecules become more disordered (ordered) in mixtures with methanol and ethanol (formic acid), showing higher (lower) vapor pressure than that predicted by Raoult's law.
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Affiliation(s)
- Xiaoqing Yu
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Takakazu Seki
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Chun-Chieh Yu
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Kai Zhong
- University
of Groningen, Zernike Institute
for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Shumei Sun
- Department
of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, 100875 Beijing, China
| | - Masanari Okuno
- Department
of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, 153-8902 Tokyo, Japan
| | - Ellen H. G. Backus
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Johannes Hunger
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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