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Voci S, Dick JE. An electrochemical perspective on the interfacial width between two immiscible liquid phases. CURRENT OPINION IN ELECTROCHEMISTRY 2023; 39:101244. [PMID: 37538354 PMCID: PMC10399975 DOI: 10.1016/j.coelec.2023.101244] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
Molecular dynamics simulations and vibrational sum-frequency spectroscopy are historically the main techniques applied to the description of the molecular structure and dynamics of the immiscible liquid/liquid interface. A molecular sharpness is estimated for oil/water interfaces, with an interfacial width that extends from hundreds of Å to 1 nm. However, electrochemical studies have elucidated a deeper liquid/liquid interface on the order of several micrometers. The breaking down of single-entity electrochemistry to simpler systems and the combination of high-resolution microscopies is confirming a larger extension of the interface. What can be the role of the electrochemist in clarifying this fundamental question? We try to give a suggestion at the end of a brief historical overview of the liquid/liquid interface studies.
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Degoulange D, Pandya R, Deschamps M, Skiba D, Gallant B, Gigan S, de Aguiar H, Grimaud A. Direct imaging of micrometer-thick interfaces in salt-salt aqueous biphasic systems. Proc Natl Acad Sci U S A 2023; 120:e2220662120. [PMID: 37068232 PMCID: PMC10151592 DOI: 10.1073/pnas.2220662120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/26/2023] [Indexed: 04/19/2023] Open
Abstract
Unlike the interface between two immiscible electrolyte solutions (ITIES) formed between water and polar solvents, molecular understanding of the liquid-liquid interface formed for aqueous biphasic systems (ABSs) is relatively limited and mostly relies on surface tension measurements and thermodynamic models. Here, high-resolution Raman imaging is used to provide spatial and chemical resolution of the interface of lithium chloride - lithium bis(trifluoromethanesulfonyl)imide - water (LiCl-LiTFSI-water) and HCl-LiTFSI-water, prototypical salt-salt ABSs found in a range of electrochemical applications. The concentration profiles of both TFSI anions and water are found to be sigmoidal thus not showing any signs of a positive adsorption for both salts and solvent. More striking, however, is the length at which the concentration profiles extend, ranging from 11 to 2 µm with increasing concentrations, compared to a few nanometers for ITIES. We thus reveal that unlike ITIES, salt-salt ABSs do not have a molecularly sharp interface but rather form an interphase with a gradual change of environment from one phase to the other. This knowledge represents a major stepping-stone in the understanding of aqueous interfaces, key for mastering ion or electron transfer dynamics in a wide range of biological and technological settings including novel battery technologies such as membraneless redox flow and dual-ion batteries.
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Affiliation(s)
- Damien Degoulange
- Chimie du Solide et de l’Energie, UMR 8260, Collège de France,75231 Cedex 05Paris, France
- Sorbonne Université,75006Paris, France
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
| | - Raj Pandya
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
- Department of Physics, Cavendish Laboratory, University of Cambridge, CambridgeCB3 0HE, United Kingdom
| | - Michael Deschamps
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
- CNRS, Conditions Extrêmes et Matériaux : Haute Température et Irradiation, UPR3079, Université d'Orléans,45071Orléans, France
| | - Dhyllan A. Skiba
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Betar M. Gallant
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
| | - Hilton B. de Aguiar
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
| | - Alexis Grimaud
- Chimie du Solide et de l’Energie, UMR 8260, Collège de France,75231 Cedex 05Paris, France
- Sorbonne Université,75006Paris, France
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA02467
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3
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Zhou T, McCue A, Ghadar Y, Bakó I, Clark AE. Structural and Dynamic Heterogeneity of Capillary Wave Fronts at Aqueous Interfaces. J Phys Chem B 2017; 121:9052-9062. [PMID: 28871781 DOI: 10.1021/acs.jpcb.7b07406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using a unique combination of slab-layering analyses and identification of truly interfacial molecules, this work examines water/vapor and water/n-hexane interfaces, specifically the structural and dynamic perturbations of the interfacial water molecules at different locations within the surface capillary waves. From both the structural and dynamic properties analyzed, it is found that these interfacial water molecules dominate the perturbations within the interfacial region, which can extend deep into the water phase relative to the Gibbs dividing surface. Of more importance is the demonstration of structural and dynamic heterogeneity of the interfacial water molecules at the capillary wave front, as indicated by the dipole orientation and the structural and dynamic behavior of hydrogen bonds and their networks.
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Affiliation(s)
- Tiecheng Zhou
- Department of Chemistry and the Materials Science and Engineering Program, Washington State University , Pullman, 99164-2920 Washington, United States
| | - Alex McCue
- Department of Chemistry and the Materials Science and Engineering Program, Washington State University , Pullman, 99164-2920 Washington, United States
| | - Yasaman Ghadar
- Department of Chemistry and the Materials Science and Engineering Program, Washington State University , Pullman, 99164-2920 Washington, United States
| | - Imre Bakó
- Institute of Organic Chemistry Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar Tudosók Körútja 2, P.O. Box 286, 1519 Budapest, Hungary
| | - Aurora E Clark
- Department of Chemistry and the Materials Science and Engineering Program, Washington State University , Pullman, 99164-2920 Washington, United States
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4
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Toth PS, Dryfe RAW. Novel organic solvents for electrochemistry at the liquid/liquid interface. Analyst 2015; 140:1947-54. [DOI: 10.1039/c4an02250e] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 5-nonanone organic phase has been shown to be a stable solvent for use in electrochemistry, ion and electron transfer has been studied at the organic/water interface.
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Affiliation(s)
- Peter S. Toth
- School of Chemistry
- University of Manchester
- Manchester
- UK
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5
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Toth PS, Ramasse QM, Velický M, Dryfe RAW. Functionalization of graphene at the organic/water interface. Chem Sci 2014; 6:1316-1323. [PMID: 29560218 PMCID: PMC5811094 DOI: 10.1039/c4sc03504f] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 11/20/2014] [Indexed: 12/05/2022] Open
Abstract
A simple method for the deposition of noble metal (Pd, Au) nanoparticles on a free-standing chemical vapour deposited graphene monolayer is reported. Metal deposition can proceed using either spontaneous or electrochemically-controlled processes. The resultant nanoclusters are characterized using atomic force and electron microscopy techniques, and mapping mode Raman spectroscopy.
A simple method for the deposition of noble metal (Pd, Au) nanoparticles on a free-standing chemical vapour deposited graphene (CVD GR) monolayer is reported. The method consists of assembling the high purity CVD GR, by transfer from poly (methyl methacrylate) (PMMA), at the organic/water interface. Metal deposition can then proceed using either spontaneous or electrochemically-controlled processes. The resultant graphene-based metal nanoclusters are characterized using atomic force and electron microscopy techniques, and the location of the nanostructures underneath the graphene layer is determined from the position and the intensity changes of the Raman bands (D, G, 2D). This novel process for decoration of a single-layer graphene sheet with metal nanoparticles using liquid/liquid interfaces opens an alternative and useful way to prepare low dimensional carbon-based nanocomposites and electrode materials.
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Affiliation(s)
- Peter S Toth
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . ; Tel: +44 (0)161-306-4522
| | - Quentin M Ramasse
- SuperSTEM Laboratory , STFC Daresbury Campus , Daresbury WA4 4AD , UK
| | - Matěj Velický
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . ; Tel: +44 (0)161-306-4522
| | - Robert A W Dryfe
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . ; Tel: +44 (0)161-306-4522
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6
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Hou B, Laanait N, Yu H, Bu W, Yoon J, Lin B, Meron M, Luo G, Vanysek P, Schlossman ML. Ion Distributions at the Water/1,2-Dichloroethane Interface: Potential of Mean Force Approach to Analyzing X-ray Reflectivity and Interfacial Tension Measurements. J Phys Chem B 2013; 117:5365-78. [DOI: 10.1021/jp401892y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Binyang Hou
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
| | - Nouamane Laanait
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
| | - Hao Yu
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
| | - Wei Bu
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
| | - Jaesung Yoon
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
| | - Binhua Lin
- The
Center for Advanced Radiation
Sources, University of Chicago, Chicago,
Illinois 60637, United States
| | - Mati Meron
- The
Center for Advanced Radiation
Sources, University of Chicago, Chicago,
Illinois 60637, United States
| | - Guangming Luo
- BSRF, Institute of High Energy
Physics, Chinese Academy of Sciences, Beijing,
100049, China
| | - Petr Vanysek
- Department of Chemistry & Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Mark L. Schlossman
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois
60607, United States
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Martin-Gassin G, Gassin PM, Couston L, Diat O, Benichou E, Brevet PF. Second harmonic generation monitoring of nitric acid extraction by a monoamide at the water–dodecane interface. Phys Chem Chem Phys 2011; 13:19580-6. [DOI: 10.1039/c1cp22179e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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McFearin CL, Richmond GL. The unique molecular behavior of water at the chloroform-water interface. APPLIED SPECTROSCOPY 2010; 64:986-994. [PMID: 20828435 DOI: 10.1366/000370210792434288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The molecular bonding and orientation of water at the chloroform-water interface has been examined in this study using vibrational sum-frequency spectroscopy (VSFS). The results provide a key puzzle piece towards our understanding of the systematic changes in the interfacial bonding and orientation of water that occur with variations in the polarity of the organic phase, especially when compared with previous studies of different liquid-liquid interfacial systems. In these VSFS studies the OH spectral responses of interfacial water molecules are used to characterize the interactions between water and the organic phase. The spectral analysis, aided by isotopic dilution studies, shows that the moderate polarity of the chloroform phase results in a mixed interfacial region with stronger organic-water bonding and fewer bonding interactions between adjacent water molecules than was previously found for studies of non-polar organic liquid-water interfaces. Even with the more mixed interfacial region and stronger organic-water interactions, interfacial water retains a significant amount of orientational ordering. These results are compared with recent predictions from molecular dynamics simulations about how molecules behave at the chloroform-water interface.
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Affiliation(s)
- Cathryn L McFearin
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
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10
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Geysermans P, Pontikis V. Interfacial layering and capillary roughness in immiscible liquids. J Chem Phys 2010; 133:074706. [DOI: 10.1063/1.3471384] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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11
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Perera JM, Stevens GW. Spectroscopic studies of molecular interaction at the liquid–liquid interface. Anal Bioanal Chem 2009; 395:1019-32. [DOI: 10.1007/s00216-009-2855-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 05/11/2009] [Accepted: 05/12/2009] [Indexed: 10/20/2022]
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12
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Affiliation(s)
- Stefan Balaz
- Department of Pharmaceutical Sciences, College of Pharmacy, North Dakota State University, Fargo, North Dakota 58105, USA.
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13
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Schlossman ML, Tikhonov AM. Molecular ordering and phase behavior of surfactants at water-oil interfaces as probed by X-ray surface scattering. Annu Rev Phys Chem 2008; 59:153-77. [PMID: 17988204 DOI: 10.1146/annurev.physchem.59.032607.093822] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Surfactants have their primary utility, both scientific and industrial, at the liquid-liquid interface. We review recent X-ray surface scattering experiments that probe the molecular ordering and phase behavior of surfactants at the water-oil interface. The presence of the oil modifies the interfacial ordering in a manner that cannot be understood simply from analogies with studies of Langmuir monolayers of surfactants at the water-vapor interface or from the traditional view that the solvent is fully mixed with the interfacial surfactants. These studies explored the role of chain flexibility and head group interactions on the ordering of long-chain alkanols and alkanoic acids. Small changes in the surfactant may produce large changes in the interfacial ordering. The interfacial monolayer can be spatially homogeneous or inhomogeneous. Investigators have observed interfacial phase transitions as a function of temperature between homogenous phases, as well as between homogeneous and inhomogeneous phases. Finally, varying the solvent chain length can alter the fundamental character of the phase transitions and lead to the formation of multilayer interfacial structures.
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Affiliation(s)
- Mark L Schlossman
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
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14
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Understanding how organic solvent polarity affects water structure and bonding at halocarbon–water interfaces. J Mol Liq 2007. [DOI: 10.1016/j.molliq.2007.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Kajimoto S, Yoshii N, Hobley J, Fukumura H, Okazaki S. Electrostatic potential gap at the interface between triethylamine and water phases studied by molecular dynamics simulation. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.09.077] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Luo G, Malkova S, Yoon J, Schultz DG, Lin B, Meron M, Benjamin I, Vanýsek P, Schlossman ML. Ion distributions at the nitrobenzene–water interface electrified by a common ion. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2006.03.051] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Luo G, Malkova S, Pingali SV, Schultz DG, Lin B, Meron M, Benjamin I, Vanysek P, Schlossman ML. Structure of the Interface between Two Polar Liquids: Nitrobenzene and Water. J Phys Chem B 2006; 110:4527-30. [PMID: 16526678 DOI: 10.1021/jp057103u] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synchrotron X-ray reflectivity is used to study the electron density as a function of depth through the bulk nitrobenzene-water interface at four different temperatures. The measured interfacial width differs from the predictions of capillary wave theory with a progressively smaller deviation as the temperature is raised. Computer simulations suggest the presence of both molecular layering and dipole ordering parallel to the interface. Either layering or a bending rigidity, that can result from dipole ordering, can explain these measurements.
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