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Gündoğdu G, Yılmaz Topuzlu E, Mutlu F, Ertekin UE, Okur HI. Oil-in-Water Emulsions Probed Using Fluorescence Multivariate-Curve-Resolution Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:13116-13121. [PMID: 38861700 DOI: 10.1021/acs.langmuir.4c01018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Hydrophobic surfaces in contact with aqueous media are omnipresent in nature. A plethora of key biological and physiological processes occur at the interface of immiscible fluids. Besides its fundamental importance, probing such interfaces is rather challenging, especially when one medium is bathed in the other. Herein, we demonstrate a fluorescence-based method that probes the oil-water interface and interfacial processes through surface dielectric perturbations. The fluorescence response of Nile Red is measured in hexadecane in water nanoemulsions. Three major spectral components appear: two from the bulk liquid media (hexadecane and water) and a distinct band at around 640 nm due to the interfacial component. Such spectra are deconvoluted using the multivariate-curve-resolution algorithm, and interface-correlated fluorescence spectra are attained. The influence of anionic sodium dodecylbenzenesulfonate (SDBS) and cationic cetyltrimethylammonium bromide (CTAB) surfactants on the oil-water interface is elucidated with concentration-dependent measurements. A charge-dependent spectral shift is observed. The interface correlated band at 641 nm for bare hexadecane nanoemulsions red shifts in the presence of anionic surfactants, indicating an apparent dielectric increase. In contrast, the same band gradually blue shifts with increasing cationic surfactant concentration, indicating an apparent interface dielectric decrease. Such a method can be utilized to probe alterations at interfaces beyond the oil/water interface.
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Affiliation(s)
- Gülsüm Gündoğdu
- Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
- National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
- Department of Energy Science and Technology, Faculty of Science, Turkish-German University, Istanbul 34820, Turkey
| | - Ezgi Yılmaz Topuzlu
- Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
- National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
| | - Ferhat Mutlu
- Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
| | - Umay E Ertekin
- Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
| | - Halil I Okur
- Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
- National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
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2
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Shen C, Zhang H, Ocko BM. Reconstructing the reflectivity of liquid surfaces from grazing incidence X-ray off-specular scattering data. J Appl Crystallogr 2024; 57:714-727. [PMID: 38846761 PMCID: PMC11151673 DOI: 10.1107/s1600576724002887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 04/01/2024] [Indexed: 06/09/2024] Open
Abstract
The capillary wave model of a liquid surface predicts both the X-ray specular reflection and the diffuse scattering around it. A quantitative method is presented to obtain the X-ray reflectivity (XRR) from a liquid surface through the diffuse scattering data around the specular reflection measured using a grazing incidence X-ray off-specular scattering (GIXOS) geometry at a fixed horizontal offset angle with respect to the plane of incidence. With this approach the entire Qz -dependent reflectivity profile can be obtained at a single, fixed incident angle. This permits a much faster acquisition of the profile than with conventional reflectometry, where the incident angle must be scanned point by point to obtain a Qz -dependent profile. The XRR derived from the GIXOS-measured diffuse scattering, referred to in this paper as pseudo-reflectivity, provides a larger Qz range compared with the reflectivity measured by conventional reflectometry. Transforming the GIXOS-measured diffuse scattering profile to pseudo-XRR opens up the GIXOS method to widely available specular XRR analysis software tools. Here the GIXOS-derived pseudo-XRR is compared with the XRR measured by specular reflectometry from two simple vapor-liquid interfaces at different surface tension, and from a hexadecyltri-methyl-ammonium bromide monolayer on a water surface. For the simple liquids, excellent agreement (beyond 11 orders of magnitude in signal) is found between the two methods, supporting the approach of using GIXOS-measured diffuse scattering to derive reflectivities. Pseudo-XRR obtained at different horizontal offset angles with respect to the plane of incidence yields indistinguishable results, and this supports the robustness of the GIXOS-XRR approach. The pseudo-XRR method can be extended to soft thin films on a liquid surface, and criteria are established for the applicability of the approach.
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Affiliation(s)
- Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Honghu Zhang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Benjamin M. Ocko
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
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3
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Ullmann K, Fachet L, Nirschl H, Leneweit G. Monolayer/Bilayer Equilibrium of Phospholipids in Gel or Liquid States: Interfacial Adsorption via Monomer or Liposome Diffusion? Gels 2023; 9:803. [PMID: 37888376 PMCID: PMC10606027 DOI: 10.3390/gels9100803] [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: 09/05/2023] [Revised: 09/25/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
Phospholipids (PLs) are widely used in the pharma industry and a better understanding of their behavior under different conditions is helpful for applications such as their use as medical transporters. The transition temperature Tm affects the lipid conformation and the interfacial tension between perfluoroperhydrophenanthrene (PFP) and an aqueous suspension of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), as well as a mixture of these PLs with cholesterol. Interfacial tensions were measured with the Du Noüy ring at quasi-equilibrium; the area per molecule was calculated according to the Gibbsian approach and a time-dependent tension gradient. Results show that the time tε to reach quasi-equilibrium was shorter when the temperature was above Tm, indicating a faster adsorption process (tε,DPPC,36 °C = 48 h, tε,DPPC,48 °C = 24 h) for PL in the liquid crystalline state than in the gel state (T < Tm). In addition, concentration-dependent results of the interfacial tension revealed that above the respective Tm and at all concentrations c > 0.1 mM, the average minimum interfacial tension for DPPC and DSPC (14.1 mN/m and 15.3 mN/m) does not differ significantly between those two lipids. Equilibrium between monolayers and bilayers shows that for T < Tm, surface pressures ∏ ≈ 31 mN/m are reached while for T > Tm, ∏ ≈ 41 mN/m. Mixtures with cholesterol only reach ∏ ≤ 31 mN/m Tm, with no significant difference between the two PLs. The higher interfacial tension of the mixture indicates stabilization of the liposomal conformation in the aqueous phase by the addition of cholesterol. The high diffusion coefficients show that adsorption is mainly based on liposomes.
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Affiliation(s)
- Kirsten Ullmann
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Lea Fachet
- Independent Researcher, 76131 Karlsruhe, Germany
| | - Hermann Nirschl
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Gero Leneweit
- Carl Gustav Carus-Institute, Association for the Promotion of Cancer Therapy, Allmendstr. 55, 75223 Niefern-Oeschelbronn, Germany
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4
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Hacmon S, Liber SR, Shool L, Butenko AV, Atkins A, Sloutskin E. "Magic Numbers" in Self-Faceting of Alcohol-Doped Emulsion Droplets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301637. [PMID: 37259270 DOI: 10.1002/smll.202301637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/20/2023] [Indexed: 06/02/2023]
Abstract
Oil-in-water emulsion droplets spontaneously adopt, below some temperature Td , counterintuitive faceted and complex non-spherical shapes while remaining liquid. This transition is driven by a crystalline monolayer formed at the droplets' surface. Here, we show that ppm-level doping of the droplet's bulk by long-chain alcohols allows tuning Td by >50 °C, implying formation of drastically different interfacial structures. Furthermore, "magic" alcohol chain lengths maximize Td . This we show to arise from self-assembly of mixed alcohol:alkane interfacial structures of stacked alkane layers, co-crystallized with hydrogen-bonded alcohol dimers. These structures are accounted for theoretically and resolved by direct cryogenic transmission electron microscopy (cryoTEM), confirming the proposed structures. The discovered tunability of key properties of commonly-used emulsions by minute concentrations of specific bulk additives should benefit these emulsions' technological applicability.
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Affiliation(s)
- Sagi Hacmon
- Physics Department, Bar-Ilan University, Ramat Gan, 529002, Israel
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
| | - Shir R Liber
- Physics Department, Bar-Ilan University, Ramat Gan, 529002, Israel
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
| | - Lee Shool
- Physics Department, Bar-Ilan University, Ramat Gan, 529002, Israel
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
| | - Alexander V Butenko
- Physics Department, Bar-Ilan University, Ramat Gan, 529002, Israel
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
| | - Ayelet Atkins
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
| | - Eli Sloutskin
- Physics Department, Bar-Ilan University, Ramat Gan, 529002, Israel
- Bar-Ilan Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan, 529002, Israel
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5
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Bui T, Frampton H, Huang S, Collins IR, Striolo A, Michaelides A. Water/oil interfacial tension reduction - an interfacial entropy driven process. Phys Chem Chem Phys 2021; 23:25075-25085. [PMID: 34738605 DOI: 10.1039/d1cp03971g] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interfacial tension (IFT) of a fluid-fluid interface plays an important role in a wide range of applications and processes. When low IFT is desired, surface active compounds (e.g. surfactants) can be added to the system. Numerous attempts have been made to relate changes in IFT arising from such compounds to the specific nature of the interface. However, the IFT is controlled by an interplay of factors such as temperature and molecular structure of surface-active compounds, which make it difficult to predict IFT as those conditions change. In this study, we present the results from molecular dynamics simulations revealing the specific role surfactants play in IFT. We find that, in addition to reducing direct contact between the two fluids, surfactants serve to increase the disorder at the interface (related to interfacial entropy) and consequently reduce the water/oil IFT, especially when surfactants are present at high surface density. Our results suggest that surfactants that yield more disordered interfacial films (e.g. with flexible and/or unsaturated tails) reduce the water/oil IFT more effectively than surfactants which yield highly ordered interfacial films. Our results shed light on some of the factors that control IFT and could have important practical implications in industrial applications such as the design of cosmetics, food products, and detergents.
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Affiliation(s)
- Tai Bui
- Thomas Young Centre and London Centre for Nanotechnology, and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK. .,BP Exploration Operating Co. Ltd, Chertsey Road, Sunbury-on-Thames TW16 7LN, UK.,Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Harry Frampton
- BP Exploration Operating Co. Ltd, Chertsey Road, Sunbury-on-Thames TW16 7LN, UK
| | - Shanshan Huang
- BP Exploration Operating Co. Ltd, Chertsey Road, Sunbury-on-Thames TW16 7LN, UK
| | - Ian R Collins
- BP Exploration Operating Co. Ltd, Chertsey Road, Sunbury-on-Thames TW16 7LN, UK
| | - Alberto Striolo
- Department of Chemical Engineering, University College London, Gower Street, London WC1E 6BT, UK.,School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Angelos Michaelides
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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6
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Baggio BF, Grunder Y. In Situ X-Ray Techniques for Electrochemical Interfaces. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2021; 14:87-107. [PMID: 33940932 DOI: 10.1146/annurev-anchem-091020-100631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This article reviews progress in the study of materials using X-ray-based techniques from an electrochemistry perspective. We focus on in situ/in operando surface X-ray scattering, X-ray absorption spectroscopy, and the combination of both methods. The background of these techniques together with key concepts is introduced. Key examples of in situ and in operando investigation of liquid-solid and liquid-liquid interfaces are presented. X-ray scattering and spectroscopy have helped to develop an understanding of the underlying atomic and molecular processes associated with electrocatalysis, electrodeposition, and battery materials. We highlight recent developments, including resonant surface diffraction and time-resolved studies.
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Affiliation(s)
- Bruna F Baggio
- Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom;
| | - Yvonne Grunder
- Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom;
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7
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Fan T, Chen L, Xia X, Wu Y, Zhang J, Yin K, Liu F, Yan Z. Dissipative Particle Dynamics Quantitative Simulation of the Formation Mechanism and Emulsification Driving Force of Deep Eutectic Solvent-Based Surfactant-Free and Water-Free Microemulsion. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c06193] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Taotao Fan
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Li Chen
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Xiaomeng Xia
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yuehang Wu
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jianwei Zhang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - KangLing Yin
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Feng Liu
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Zongcheng Yan
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
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8
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Peng M, Duignan TT, Nguyen CV, Nguyen AV. From Surface Tension to Molecular Distribution: Modeling Surfactant Adsorption at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2237-2255. [PMID: 33559472 DOI: 10.1021/acs.langmuir.0c03162] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Surfactants are centrally important in many scientific and engineering fields and are used for many purposes such as foaming agents and detergents. However, many challenges remain in providing a comprehensive understanding of their behavior. Here, we provide a brief historical overview of the study of surfactant adsorption at the air-water interface, followed by a discussion of some recent advances in this area from our group. The main focus is on incorporating an accurate description of the adsorption layer thickness of surfactant at the air-water interface. Surfactants have a wide distribution at the air-water interface, which can have a significant effect on important properties such as the surface excess, surface tension, and surface potential. We have developed a modified Poisson-Boltzmann (MPB) model to describe this effect, which we outline here. We also address the remaining challenges and future research directions in this area. We believe that experimental techniques, modeling, and simulation should be combined to form a holistic picture of surfactant adsorption at the air-water interface.
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Affiliation(s)
- Mengsu Peng
- School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Timothy T Duignan
- School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Cuong V Nguyen
- School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Anh V Nguyen
- School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia
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9
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Fainerman V, Aksenenko E, Kovalchuk V, Mucic N, Javadi A, Liggieri L, Ravera F, Loglio G, Makievski A, Schneck E, Miller R. New view of the adsorption of surfactants at water/alkane interfaces - Competitive and cooperative effects of surfactant and alkane molecules. Adv Colloid Interface Sci 2020; 279:102143. [PMID: 32224338 DOI: 10.1016/j.cis.2020.102143] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 01/03/2023]
Abstract
The theoretical description of the adsorption of surfactants at interfaces between aqueous solutions and oil was based over a very long time on models derived for the solution/air interface. Thus, most of the experimentally observed peculiarities could not be specifically considered but were merely interpreted in terms of a penetration of oil molecules into the alkyl chain layer of the adsorbed surfactant molecules. These penetrating oil molecules enhance the surfactant adsorption as compared to the water/air interface. Later on, for the special situations at water/oil interfaces a competitive adsorption of surfactant and oil molecules was postulated, allowing a much better description of experimental data. This picture, however, was unable to explain why the interfacial tension of the water/oil interface decreases very quickly when extremely small amounts of surfactants are added to the water. This effect cannot be of competitive nature, but a cooperativity of surfactant and oil molecules forming a mixed adsorption layer is required instead. This cooperative effect means that already few surfactant molecules adsorbed at the interface can induce a significant ordering of oil molecules in the interfacial layer. This new interfacial structure, in turn, attracts further surfactant molecules to adsorb. Improving the theoretical description of experimental data was finally achieved by applying suitable adsorption models for the two adsorbing compounds, i.e. a Frumkin adsorption model for the oil molecules and a Langmuir, Frumkin, or reorientation model for the adsorbing surfactant molecules. Here, the progress in modelling surfactant adsorption at water/oil interfaces is discussed mainly for the homologous series of the cationic surfactants CnTAB, of the anionic surfactant SDS, and members of the homologous series of the non-ionic surfactants CnDMPO at water/alkane interfaces.
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10
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Liber SR, Marin O, Butenko AV, Ron R, Shool L, Salomon A, Deutsch M, Sloutskin E. Polyhedral Water Droplets: Shape Transitions and Mechanism. J Am Chem Soc 2020; 142:8672-8678. [DOI: 10.1021/jacs.0c00184] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Shir R. Liber
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Orlando Marin
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Alexander V. Butenko
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Racheli Ron
- Chemistry Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lee Shool
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Adi Salomon
- Chemistry Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Moshe Deutsch
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Eli Sloutskin
- Physics Department & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel
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11
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Moghimikheirabadi A, Ilg P, Sagis LMC, Kröger M. Surface Rheology and Structure of Model Triblock Copolymers at a Liquid–Vapor Interface: A Molecular Dynamics Study. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b01995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Patrick Ilg
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
| | - Leonard M. C. Sagis
- Food Physics Group, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zürich, Zürich CH-8093, Switzerland
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12
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Zhang J, Chen L, Wang A, Yan Z. Dissipative Particle Dynamics Simulation of Ionic Liquid-Based Microemulsion: Quantitative Properties and Emulsification Mechanism. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b05660] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jianwei Zhang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Li Chen
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Aili Wang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
- School of Chemistry and Material Science, Ludong University, Yantai 264025, China
| | - Zongcheng Yan
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
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13
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Moghimikheirabadi A, Sagis LMC, Kröger M, Ilg P. Gas–liquid phase equilibrium of a model Langmuir monolayer captured by a multiscale approach. Phys Chem Chem Phys 2019; 21:2295-2306. [PMID: 30328439 DOI: 10.1039/c8cp05447a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We here propose a multiscale approach that allows the gas–liquid expanded phase equilibrium of a Langmuir monolayer to be studied efficiently by coarse-grained two-dimensional simulations and density functional theory.
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Affiliation(s)
| | | | - Martin Kröger
- Polymer Physics
- Department of Materials
- ETH Zürich
- CH-8093 Zürich
- Switzerland
| | - Patrick Ilg
- School of Mathematical
- Physical and Computational Sciences
- University of Reading
- Reading
- UK
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14
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Kovacik F, Okur HI, Smolentsev N, Scheu R, Roke S. Hydration mediated interfacial transitions on mixed hydrophobic/hydrophilic nanodroplet interfaces. J Chem Phys 2018; 149:234704. [PMID: 30579299 DOI: 10.1063/1.5035161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Interfacial phase transitions are of fundamental importance for climate, industry, and biological processes. In this work, we observe a hydration mediated surface transition in supercooled oil nanodroplets in aqueous solutions using second harmonic and sum frequency scattering techniques. Hexadecane nanodroplets dispersed in water freeze at a temperature of ∼15 °C below the melting point of the bulk alkane liquid. Addition of a trimethylammonium bromide (CXTA+) type surfactant with chain length equal to or longer than that of the alkane causes the bulk oil droplet freezing transition to be preceded by a structural interfacial transition that involves water, oil, and the surfactant. Upon cooling, the water loses some of its orientational order with respect to the surface normal, presumably by reorienting more parallel to the oil interface. This is followed by the surface oil and surfactant alkyl chains losing some of their flexibility, and this chain stretching induces alkyl chain ordering in the bulk of the alkane phase, which is then followed by the bulk transition occurring at a 3 °C lower temperature. This behavior is reminiscent of surface freezing observed in planar tertiary alkane/surfactant/water systems but differs distinctively in that it appears to be induced by the interfacial water and requires only a very small amount of surfactant.
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Affiliation(s)
- Filip Kovacik
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Halil I Okur
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Nikolay Smolentsev
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Rüdiger Scheu
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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15
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Moghimikheirabadi A, Sagis LM, Ilg P. Effective interaction potentials for model amphiphilic surfactants adsorbed at fluid-fluid interfaces. Phys Chem Chem Phys 2018; 20:16238-16246. [PMID: 29863213 DOI: 10.1039/c8cp01632a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computer simulations are a useful tool to explore the effects of interactions and structure of surfactants on interfacial microstructure and properties. Starting with "molecular-level", three-dimensional reference systems of short amphiphilic surfactants at fluid-fluid interfaces, we here derive effective interaction potentials for the corresponding two-dimensional systems of structureless particles confined to the interface plane. These reference systems are comprised of two immiscible mono atomic fluids (water- and oil-like particles) and nonionic linear amphiphilic surfactants. Our results show that coarse grained interaction potentials are only weakly dependent on surface concentration but their behavior is strongly dependent on surfactant interactions. The coarse grained system preserves the in-plane surfactant center-of-mass pair correlation function at the interface and the results of surface pressure-area isotherms are in a good agreement. This approach can be extended straightforwardly to other types of surfactants at both fluid-fluid and fluid-gas interfaces providing us with an effective pairwise interaction potential for the surfactant monolayer. These effective interactions can be used to explore large-scale self-assembly within the monolayer especially at low surface concentrations where reference simulations are extremely time-consuming.
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16
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Zdrali E, Chen Y, Okur HI, Wilkins DM, Roke S. The Molecular Mechanism of Nanodroplet Stability. ACS NANO 2017; 11:12111-12120. [PMID: 29224343 DOI: 10.1021/acsnano.7b05100] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Mixtures of nano- and microscopic oil droplets in water have recently been rediscovered as miniature reaction vessels in microfluidic environments and are important constituents of many environmental systems, food, personal care, and medical products. The oil nanodroplet/water interface stabilized by surfactants determines the physicochemical properties of the droplets. Surfactants are thought to stabilize nanodroplets by forming densely packed monolayers that shield the oil phase from the water. This idea has been inferred from droplet stability measurements in combination with molecular structural data obtained from extended planar interfaces. Here, we present a molecular level investigation of the surface structure and stability of nanodroplets and show that the surface structure of nanodroplets is significantly different from that of extended planar interfaces. Charged surfactants form monolayers that are more than 1 order of magnitude more dilute than geometrically packed ones, and there is no experimental correlation between stability and surfactant surface density. Moreover, dilute negatively charged surfactant monolayers produce more stable nanodroplets than dilute positively charged and dense geometrically packed neutral surfactant monolayers. Droplet stability is found to depend on the relative cooperativity between charge-charge, charge-dipole, and hydrogen-bonding interactions. The difference between extended planar interfaces and nanoscale interfaces stems from a difference in the thermally averaged total charge-charge interactions in the two systems. Low dielectric oil droplets with a size smaller than the Debye length in oil permit repulsive interactions between like charges from opposing interfaces in small droplets. This behavior is generic and extends up to the micrometer length scale.
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Affiliation(s)
- Evangelia Zdrali
- Laboratory for Fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Yixing Chen
- Laboratory for Fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Halil I Okur
- Laboratory for Fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - David M Wilkins
- Laboratory of Computational Science and Modeling, Institute of Materials, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for Fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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17
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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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18
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Pham TT, Jonchère A, Dufrêche JF, Brevet PF, Diat O. Analysis of the second harmonic generation signal from a liquid/air and liquid/liquid interface. J Chem Phys 2017; 146:144701. [DOI: 10.1063/1.4979879] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thanh Tung Pham
- Institut de Chimie Séparative de Marcoule, UMR 5257 (CEA, CNRS, Université de Montpellier, ENSCM), BP17171, 30207 Bagnols sur Cèze, France
| | - Alban Jonchère
- Institut de Chimie Séparative de Marcoule, UMR 5257 (CEA, CNRS, Université de Montpellier, ENSCM), BP17171, 30207 Bagnols sur Cèze, France
| | - Jean-François Dufrêche
- Institut de Chimie Séparative de Marcoule, UMR 5257 (CEA, CNRS, Université de Montpellier, ENSCM), BP17171, 30207 Bagnols sur Cèze, France
| | - Pierre-François Brevet
- Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex, France
| | - Olivier Diat
- Institut de Chimie Séparative de Marcoule, UMR 5257 (CEA, CNRS, Université de Montpellier, ENSCM), BP17171, 30207 Bagnols sur Cèze, France
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19
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Popova H, Milchev A, Egorov SA. Modeling the interfacial tension dependence on composition and stiffness of nonionic surfactants on liquid–liquid interfaces. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2016.05.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Yang F, Wu W, Chen S, Gan W. The ionic strength dependent zeta potential at the surface of hexadecane droplets in water and the corresponding interfacial adsorption of surfactants. SOFT MATTER 2017; 13:638-646. [PMID: 27991633 DOI: 10.1039/c6sm02174c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An anomalous maximum in the ionic strength dependent electrophoretic mobility curves has been observed in previous reports from particles dispersed in colloids. This maximum has been considered anomalous because it is contradictory with the Gouy-Chapman model. The existence of such a maximum has been attributed to specific ionic adsorption, a hairy layer at the surface, or the effect of the anomalous change of surface conductivity in different studies. It was also pointed out that the O'Brien-White approach based on the Gouy-Chapman model could be used to understand this maximum in electrophoretic mobility curves and lead to understandable zeta potential curves. This implied that the observed maximum was actually not "anomalous". In this work we report our simulation of ionic strength dependent zeta potential curves based on the O'Brien-White approach and experimental studies of the ionic strength dependent electrophoretic mobility of the hexadecane droplets in the hexadecane-water emulsions at different pH or in the presence of sodium dodecyl sulphate at varied concentrations. In some cases, the simulation shows that the calculation with the O'Brien-White approach does change the trend in the concerned ionic strength dependent curves. However, the simulation in some other cases also leads to similar trends in the ionic strength dependent electrophoretic mobility curves and zeta potential curves. In the experiments, both the existence and non-existence of such a maximum were observed and demonstrated to be system dependent. The corresponding molecular structure of the oil-water interface was then discussed with the analyses of the zeta potential curves and second harmonic generation signals recorded at the hexadecane-water interface.
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Affiliation(s)
- Fangyuan Yang
- Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Wu
- Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shunli Chen
- Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, China.
| | - Wei Gan
- Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, China. and Department of Natural Science and Humanities, Shenzhen Graduate School, Harbin Institute of Technology, University Town, Shenzhen 518055, China
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21
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Hildebrandt E, Sommerling JH, Guthausen G, Zick K, Stürmer J, Nirschl H, Leneweit G. Phospholipid adsorption at oil in water versus water in oil interfaces: Implications for interfacial densities and bulk solubilities. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2015.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Smit WJ, Smolentsev N, Versluis J, Roke S, Bakker HJ. Freezing effects of oil-in-water emulsions studied by sum-frequency scattering spectroscopy. J Chem Phys 2016; 145:044706. [DOI: 10.1063/1.4959128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- W. J. Smit
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - N. Smolentsev
- Laboratory for Fundamental Biophotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - J. Versluis
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - S. Roke
- Laboratory for Fundamental Biophotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - H. J. Bakker
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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23
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Hildebrandt E, Dessy A, Sommerling JH, Guthausen G, Nirschl H, Leneweit G. Interactions between Phospholipids and Organic Phases: Insights into Lipoproteins and Nanoemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5821-5829. [PMID: 27159619 DOI: 10.1021/acs.langmuir.6b00978] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The adsorption of phosphatidylcholines (PCs), dissolved in squalene or squalane as an organic phase, was studied at the interface with water. Using profile analysis tensiometry, the equilibrium adsorption isotherms, minimum molecular interfacial areas, and solubility limits were derived. For squalene, differences in PC solubility and interfacial adsorption were found, depending on PC saturation. Compared to saturated PCs, unsaturated PCs showed a 3-fold-lower interfacial density but up to a 28-fold-higher critical aggregation concentration (CAC). In addition, the solubility limit of unsaturated PC in squalene and in its saturated form squalane diverged by a factor of 739. These findings provided evidence for steric repulsion or π-π interactions of π bonds in both solvent and solute or both effects acting complementarily. In squalane, low solubilities but high interfacial densities were found for all investigated PCs. Changes in fatty acid chain lengths showed that the influence of the increases in entropy and enthalpy on solubility is much smaller than solvent/solute interactions. Oxidation products of squalene lowered the interfacial tension, but increasing concentrations of PC expelled them from the interface. The CAC of saturated PC was increased by oxidation products of squalene whereas that of unsaturated PCs was not. Our findings indicate that the oxidation of triglycerides in lipoprotein cores can lead to increased solubility of saturated phospholipids covering the lipoproteins, contributing to destabilization, coalescence, and terminally the formation of atherosclerotic plaques. The consideration of solvent/solute interactions in molecular modeling may contribute to the interfacial tension and the corresponding kinetic or thermodynamic stability of lipoproteins. Measured areas per molecule prove that PCs form monolayers of different interfacial densities at the squalene/water interface but multilayers at the squalane/water interface. These findings showed that combinations of solvent or solute saturation affect the outcome for nanoemulsions forming either expanded or condensed monolayers or multilayers.
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Affiliation(s)
- Ellen Hildebrandt
- Karlsruhe Institute of Technology (KIT), Institute of Mechanical Process Engineering and Mechanics , 76131 Karlsruhe, Germany
- Abnoba GmbH, 75177 Pforzheim, Germany
| | | | - Jan-Hendrik Sommerling
- Karlsruhe Institute of Technology (KIT), Institute of Mechanical Process Engineering and Mechanics , 76131 Karlsruhe, Germany
- Abnoba GmbH, 75177 Pforzheim, Germany
| | - Gisela Guthausen
- Karlsruhe Institute of Technology (KIT), Institute of Mechanical Process Engineering and Mechanics , 76131 Karlsruhe, Germany
| | - Hermann Nirschl
- Karlsruhe Institute of Technology (KIT), Institute of Mechanical Process Engineering and Mechanics , 76131 Karlsruhe, Germany
| | - Gero Leneweit
- Abnoba GmbH, 75177 Pforzheim, Germany
- Carl Gustav Carus-Institute, Association for the Promotion of Cancer Therapy , 75223 Niefern-Oeschelbronn, Germany
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24
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Wu Q, Du X, Chang A, Jiang X, Yan X, Cao X, Farooqi ZH, Wu W. Bioinspired synthesis of poly(phenylboronic acid) microgels with high glucose selectivity at physiological pH. Polym Chem 2016. [DOI: 10.1039/c6py01521b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A microgel that is more sensitive towards glucose than to other saccharides is made of 4-vinylphenylboronic acid crosslinked withN,N′-bis(propene)perylene-3,4,9,10-tetracarboxyldiimide.
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Affiliation(s)
- Qingshi Wu
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
| | - Xue Du
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
| | - Aiping Chang
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
| | - Xiaomei Jiang
- Clinical Laboratory
- Huli Center for Maternal and Child Health
- Xiamen
- China
| | - Xiaoyun Yan
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
| | - Xiaoyu Cao
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
| | | | - Weitai Wu
- State Key Laboratory for Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials
- The Key Laboratory for Chemical Biology of Fujian Province
- and Department of Chemistry
- College of Chemistry and Chemical Engineering
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25
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Shi K, Lian C, Bai Z, Zhao S, Liu H. Dissipative particle dynamics study of the water/benzene/caprolactam system in the absence or presence of non-ionic surfactants. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.09.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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26
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Fang H, Wu W, Sang Y, Chen S, Zhu X, Zhang L, Niu Y, Gan W. Evidence of the adsorption of hydroxide ion at hexadecane/water interface from second harmonic generation study. RSC Adv 2015. [DOI: 10.1039/c4ra15401k] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The effect of hydroxide ion, impurities and oleic acid on molecular structure at hexadecane/water interface was studied with second harmonic generation.
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Affiliation(s)
- Hui Fang
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Wei Wu
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Yajun Sang
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Shunli Chen
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Xuefeng Zhu
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Libo Zhang
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Yuanyuan Niu
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
| | - Wei Gan
- Laboratory of Environmental Science and Technology
- Xinjiang Technical Institute of Physics & Chemistry
- Key Laboratory of Functional Materials and Devices for Special Environments
- Chinese Academy of Sciences
- Urumqi 830011
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27
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Yu H, Yzeiri I, Hou B, Chen CH, Bu W, Vanysek P, Chen YS, Lin B, Král P, Schlossman ML. Electric Field Effect on Phospholipid Monolayers at an Aqueous-Organic Liquid-Liquid Interface. J Phys Chem B 2014; 119:9319-34. [PMID: 25289837 DOI: 10.1021/jp5098525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electric potential difference across cell membranes, known as the membrane potential, plays an important role in the activation of many biological processes. To investigate the effect of the membrane potential on the molecular ordering of lipids within a biomimetic membrane, a self-assembled monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) lipids at an electrified 1,2-dichloroethane/water interface is studied with X-ray reflectivity and interfacial tension. Measurements over a range of electric potential differences, -150 to +130 mV, that encompass the range of typical biomembrane potentials demonstrate a nearly constant and stable structure whose lipid interfacial density is comparable to that found in other biomimetic membrane systems. Measurements at higher positive potentials, up to 330 mV, illustrate a monotonic decrease in the lipid interfacial density and accompanying variations in the interfacial configuration of the lipid. Molecular dynamics simulations, designed to mimic the experimental conditions, show that the measured changes in lipid configuration are due primarily to the variation in area per lipid with increasing applied electric field. Rotation of the SOPC dipole moment by the torque from the applied electric field appears to be negligible, except at the highest measured potentials. The simulations confirm in atomistic detail the measured potential-dependent characteristics of SOPC monolayers. Our hybrid study sheds light on phospholipid monolayer stability under different membrane potentials, which is important for understanding membrane processes. This study also illustrates the use of X-ray surface scattering to probe the ordering of surfactant monolayers at an electrified aqueous-organic liquid-liquid interface.
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Affiliation(s)
- Hao Yu
- †Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Irena Yzeiri
- ‡Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Binyang Hou
- †Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Chiu-Hao Chen
- †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
| | | | - Yu-Sheng Chen
- ∥The Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Binhua Lin
- ∥The Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Petr Král
- †Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States.,‡Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Mark L Schlossman
- †Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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28
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Bu W, Mihaylov M, Amoanu D, Lin B, Meron M, Kuzmenko I, Soderholm L, Schlossman ML. X-ray Studies of Interfacial Strontium–Extractant Complexes in a Model Solvent Extraction System. J Phys Chem B 2014; 118:12486-500. [DOI: 10.1021/jp508430e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
| | | | | | - Binhua Lin
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Mati Meron
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
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29
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Schuman AW, Bsaibes TS, Schlossman ML. Microphase formation at a 2D solid-gas phase transition. SOFT MATTER 2014; 10:7353-7360. [PMID: 25088351 DOI: 10.1039/c4sm01197j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Density modulated micro-separated phases (microphases) occur at 2D liquid interfaces in the form of alternating regions of high and low density domains. Brewster angle microscopy (BAM) images demonstrate the existence of microphases in cluster, stripe, and mosaic morphologies at the buried interface between hexane and water with fluoro-alkanol surfactant dissolved in the bulk hexane. At high temperature, the surfactant assembles at the interface in a 2D gaseous state. As the system is cooled additional surfactants condense onto the interface, which undergoes a 2D gas-solid phase transition. Microphase structure is observed within a few degrees of this transition in the form of clusters and labyrinthine stripes. Microphases have been observed previously in a number of other systems; nevertheless, we demonstrate that adsorption transitions at the liquid-liquid interface provide a convenient way to observe a full sequence of temperature-dependent 2D phases, from gas to cluster to stripe to mosaic to inverted stripe phases, as well as coexistence between some of these microphases. Cracking and fracture of the clusters reveal that they are a solid microphase. Theories of microphases often predict a single length scale for cluster and stripe phases as a result of the competition between an attractive and a repulsive interaction. Our observation that two characteristic length scales are required to describe clusters whose diameter is much larger than the stripe period, combined with the solid nature of the clusters, suggests that a long-range elastic interaction is relevant. These results complement earlier X-ray measurements on the same system.
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Affiliation(s)
- Adam W Schuman
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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30
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Fainerman VB, Aksenenko EV, Mucic N, Javadi A, Miller R. Thermodynamics of adsorption of ionic surfactants at water/alkane interfaces. SOFT MATTER 2014; 10:6873-6887. [PMID: 24909966 DOI: 10.1039/c4sm00463a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
On the basis of experimental data for the homologous series of alkyltrimethylammonium bromides (CnTAB) the equilibrium surface tension isotherms at three types of liquid-fluid interfaces are discussed: solution/air, solution/alkane vapor and solution/liquid alkane interfaces. It is shown that the adsorption characteristics can be described at all three interfaces by the same thermodynamic approach. In the presence of alkane molecules (in the liquid alkane phase or in the alkane vapor phase) the CnTAB adsorption layers can be best described by a co-adsorption of the alkane molecules.
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Affiliation(s)
- V B Fainerman
- Donetsk Medical University, 16 Ilych Avenue, Donetsk 83003, Ukraine
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31
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Bu W, Yu H, Luo G, Bera MK, Hou B, Schuman AW, Lin B, Meron M, Kuzmenko I, Antonio MR, Soderholm L, Schlossman ML. Observation of a Rare Earth Ion–Extractant Complex Arrested at the Oil–Water Interface During Solvent Extraction. J Phys Chem B 2014; 118:10662-74. [DOI: 10.1021/jp505661e] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Wei Bu
- 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
| | | | - Mrinal K. Bera
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Binyang Hou
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Adam W. Schuman
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Binhua Lin
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | - Mati Meron
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
| | | | | | | | - Mark L. Schlossman
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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32
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Scheu R, Chen Y, de Aguiar HB, Rankin BM, Ben-Amotz D, Roke S. Specific Ion Effects in Amphiphile Hydration and Interface Stabilization. J Am Chem Soc 2014; 136:2040-7. [DOI: 10.1021/ja4120117] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rüdiger Scheu
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bio-Engineering (IBI),
School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne, Switzerland
| | - Yixing Chen
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bio-Engineering (IBI),
School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne, Switzerland
| | - Hilton B. de Aguiar
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bio-Engineering (IBI),
School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne, Switzerland
| | - Blake M. Rankin
- Department
of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Dor Ben-Amotz
- Department
of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Sylvie Roke
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bio-Engineering (IBI),
School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne, Switzerland
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Murphy BM, Greve M, Runge B, Koops CT, Elsen A, Stettner J, Seeck OH, Magnussen OM. A novel X-ray diffractometer for studies of liquid-liquid interfaces. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:45-56. [PMID: 24365915 DOI: 10.1107/s1600577513026192] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/22/2013] [Indexed: 06/03/2023]
Abstract
The study of liquid-liquid interfaces with X-ray scattering methods requires special instrumental considerations. A dedicated liquid surface diffractometer employing a tilting double-crystal monochromator in Bragg geometry has been designed. This diffractometer allows reflectivity and grazing-incidence scattering measurements of an immobile mechanically completely decoupled liquid sample, providing high mechanical stability. The available energy range is from 6.4 to 29.4 keV, covering many important absorption edges. The instrument provides access in momentum space out to 2.54 Å(-1) in the surface normal and out to 14.8 Å(-1) in the in-plane direction at 29.4 keV. Owing to its modular design the diffractometer is also suitable for heavy apparatus such as vacuum chambers. The instrument performance is described and examples of X-ray reflectivity studies performed under in situ electrochemical control and on biochemical model systems are given.
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Affiliation(s)
- Bridget M Murphy
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Matthais Greve
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Christian T Koops
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Annika Elsen
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Jochim Stettner
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
| | - Oliver H Seeck
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany
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Fainerman VB, Mucic N, Pradines V, Aksenenko EV, Miller R. Adsorption of alkyltrimethylammonium bromides at water/alkane interfaces: competitive adsorption of alkanes and surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:13783-13789. [PMID: 24111851 DOI: 10.1021/la402782e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The adsorption of members of the homologous series of alkyl trimethylammonium bromides (C(n)TAB) is studied at water/alkane interfaces by drop profile analysis tensiometry. The results are discussed in terms of a competitive adsorption process of alkane and surfactant molecules. A thermodynamic model, derived originally for the adsorption of surfactant mixtures, is adapted such that it describes a competitive adsorption of the surfactant molecules from the aqueous phase and alkane molecules from the oil phase. This new model involves the interspecies attraction coefficient, which mutually increases the adsorption activities of the alkane and C(n)TAB. The effects of the alkyl chain length n of C(n)TABs and the influence of the number of C atoms in the alkane chain are discussed, and the physical quantities are compared to those determined at the aqueous solution/air interface. The new theoretical model for aqueous solution/oil interfaces is also compared to a theory that does not consider the adsorption of alkane. The proposed new model demonstrates good agreement with the experimental data.
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Affiliation(s)
- V B Fainerman
- Donetsk Medical University , 16 Ilych Avenue, 83003 Donetsk, Ukraine
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Mucic N, Kovalchuk N, Aksenenko E, Fainerman V, Miller R. Adsorption layer properties of alkyltrimethylammonium bromides at interfaces between water and different alkanes. J Colloid Interface Sci 2013; 410:181-7. [DOI: 10.1016/j.jcis.2013.07.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 11/26/2022]
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Fiore A, Venkateshwaran V, Garde S. Trimethylamine N-oxide (TMAO) and tert-butyl alcohol (TBA) at hydrophobic interfaces: insights from molecular dynamics simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8017-8024. [PMID: 23687932 DOI: 10.1021/la401203r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
TMAO, a potent osmolyte, and TBA, a denaturant, have similar molecular architecture but somewhat different chemistry. We employ extensive molecular dynamics simulations to quantify their behavior at vapor-water and octane-water interfaces. We show that interfacial structure-density and orientation-and their dependence on solution concentration are markedly different for the two molecules. TMAO molecules are moderately surface active and adopt orientations with their N-O vector approximately parallel to the aqueous interface. That is, not all methyl groups of TMAO at the interface point away from the water phase. In contrast, TBA molecules act as molecular amphiphiles, are highly surface active, and, at low concentrations, adopt orientations with their methyl groups pointing away and the C-O vector pointing directly into water. The behavior of TMAO at aqueous interfaces is only weakly dependent on its solution concentration, whereas that of TBA depends strongly on concentration. We show that this concentration dependence arises from their different hydrogen bonding capabilities-TMAO can only accept hydrogen bonds from water, whereas TBA can accept (donate) hydrogen bonds from (to) water or other TBA molecules. The ability to self-associate, particularly visible in TBA molecules in the interfacial layer, allows them to sample a broad range of orientations at higher concentrations. In light of the role of TMAO and TBA in biomolecular stability, our results provide a reference with which to compare their behavior near biological interfaces. Also, given the ubiquity of aqueous interfaces in biology, chemistry, and technology, our results may be useful in the design of interfacially active small molecules with the aim to control their orientations and interactions.
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Affiliation(s)
- Andrew Fiore
- The Howard P. Isermann Department of Chemical and Biological Engineering and The Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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37
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Vysotsky YB, Fomina ES, Belyaeva EA, Fainerman VB, Vollhardt D. On the inclusion of alkanes into the monolayer of aliphatic alcohols at the water/alkane vapor interface: a quantum chemical approach. Phys Chem Chem Phys 2013; 15:2159-76. [PMID: 23292086 DOI: 10.1039/c2cp43713a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the framework of the quantum chemical semiempirical PM3 method thermodynamic and structural parameters of the formation and clusterization of aliphatic alcohols C(n)H(2n+1)OH (n(OH) = 8-16) at 298 K at the water/alkane vapor C(n)H(2n+2), (n(CH(3)) = 6-16) interface were calculated. The dependencies of enthalpy, entropy and Gibbs' energy of clusterization per one monomer molecule of 2D films on the alkyl chain length of corresponding alcohols and alkanes, the molar fraction of alkanes in the monolayers and the immersion degree of alcohol molecules into the water phase were shown to be linear or stepwise. The threshold of spontaneous clusterization of aliphatic alcohols at the water/alkane vapor interface was 10-11 carbon atoms at 298 K which is in line with experimental data at the air/water interface. It is shown that the presence of alkane vapor does not influence the process of alcohol monolayer formation. The structure of these monolayers is analogous to those obtained at the air/water interface in agreement with experimental data. The inclusion of alkane molecules into the amphiphilic monolayer at the water/alkane vapor interface is possible for amphiphiles with the spontaneous clusterization threshold at the air/water interface (n(s)(0)) of at least 16 methylene units in the alkyl chain, and it does not depend on the molar fraction of alkanes in the corresponding monolayer. The inclusion of alkanes from the vapor phase into the amphiphilic monolayer also requires that the difference between the alkyl chain lengths of alcohols and alkanes is not larger than n(s)(0) - 15 and n(s)(0) - 14 for the 2D film 1 and 2D film 2, respectively.
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Affiliation(s)
- Yuri B Vysotsky
- Donetsk National Technical University, 58 Artema Str., 83000 Donetsk, Ukraine
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Davey RJ, Schroeder SLM, ter Horst JH. Keimbildung organischer Kristalle aus molekularer Sichtweise. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201204824] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Davey RJ, Schroeder SLM, ter Horst JH. Nucleation of organic crystals--a molecular perspective. Angew Chem Int Ed Engl 2013; 52:2166-79. [PMID: 23307268 DOI: 10.1002/anie.201204824] [Citation(s) in RCA: 273] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Indexed: 11/12/2022]
Abstract
The outcome of synthetic procedures for crystalline organic materials strongly depends on the first steps along the molecular self-assembly pathway, a process we know as crystal nucleation. New experimental techniques and computational methodologies have spurred significant interest in understanding the detailed molecular mechanisms by which nuclei form and develop into macroscopic crystals. Although classical nucleation theory (CNT) has served well in describing the kinetics of the processes involved, new proposed nucleation mechanisms are additionally concerned with the evolution of structure and the competing nature of crystallization in polymorphic systems. In this Review, we explore the extent to which CNT and nucleation rate measurements can yield molecular-scale information on this process and summarize current knowledge relating to molecular self-assembly in nucleating systems.
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Affiliation(s)
- Roger J Davey
- School of Chemical Engineering and Analytical Sciences, University of Manchester, The Mill, Sackville Street, Manchester M13 9PL, UK.
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Thomas PJ, Mbufu E, O'Brien P. Thin films of metals, metal chalcogenides and oxides deposited at the water–oil interface using molecular precursors. Chem Commun (Camb) 2013; 49:118-27. [DOI: 10.1039/c2cc37146d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Sanstead PJ, Florio N, Giusto K, Morris C, Lee S. Sensitivity of cationic surfactant templates to specific anions in liquid interface crystallization. J Colloid Interface Sci 2012; 376:152-9. [DOI: 10.1016/j.jcis.2012.02.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/28/2012] [Accepted: 02/29/2012] [Indexed: 10/28/2022]
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Abstract
The main aspects related to the charge transfer reactions occurring at the interface between two immiscible electrolyte solutions (ITIES) are described. The particular topics to be discussed involve simple ion transfer. Focus is given on theoretical approaches, numerical simulations, and experimental methodologies. Concerning the theoretical procedures, different computational simulations related to simple ion transfer are reviewed. The main conclusions drawn from the most accepted models are described and analyzed in regard to their relevance for explaining different aspects of ion transfer. We describe numerical simulations implementing different approaches for solving the differential equations associated with the mass transport and charge transfer. These numerical simulations are correlated with selected experimental results; their usefulness in designing new experiments is summarized. Finally, many practical applications can be envisaged regarding the determination of physicochemical properties, electroanalysis, drug lipophilicity, and phase-transfer catalysis.
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On the Characteristic Curvature of Alkyl-Polypropylene Oxide Sulfate Extended Surfactants. J SURFACTANTS DETERG 2011. [DOI: 10.1007/s11743-011-1303-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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de Aguiar HB, Strader ML, de Beer AGF, Roke S. Surface Structure of Sodium Dodecyl Sulfate Surfactant and Oil at the Oil-in-Water Droplet Liquid/Liquid Interface: A Manifestation of a Nonequilibrium Surface State. J Phys Chem B 2011; 115:2970-8. [DOI: 10.1021/jp200536k] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Hilton B. de Aguiar
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Matthew L. Strader
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Alex G. F. de Beer
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Sylvie Roke
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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46
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Tang CY, Huang Z, Allen HC. Interfacial Water Structure and Effects of Mg2+ and Ca2+ Binding to the COOH Headgroup of a Palmitic Acid Monolayer Studied by Sum Frequency Spectroscopy. J Phys Chem B 2010; 115:34-40. [PMID: 21158425 DOI: 10.1021/jp1062447] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cheng Y. Tang
- The Ohio State University, Department of Chemistry, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Zishuai Huang
- The Ohio State University, Department of Chemistry, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Heather C. Allen
- The Ohio State University, Department of Chemistry, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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47
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Sen S. “Half-hydration” at the air/water interface revealed by heterodyne-detected electronic sum frequency generation spectroscopy, polarization second harmonic generation, and molecular dynamics simulation. J Chem Phys 2010; 132:144701. [DOI: 10.1063/1.3372620] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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49
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de Aguiar HB, de Beer AGF, Strader ML, Roke S. The Interfacial Tension of Nanoscopic Oil Droplets in Water Is Hardly Affected by SDS Surfactant. J Am Chem Soc 2010; 132:2122-3. [DOI: 10.1021/ja9095158] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hilton B. de Aguiar
- Max Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Alex G. F. de Beer
- Max Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Matthew L. Strader
- Max Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Sylvie Roke
- Max Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
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50
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Frenkel YV, Gallicchio E, Das K, Levy RM, Arnold E. Molecular dynamics study of non-nucleoside reverse transcriptase inhibitor 4-[[4-[[4-[(E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2-pyrimidinyl]amino]benzonitrile (TMC278/rilpivirine) aggregates: correlation between amphiphilic properties of the drug and oral bioavailability. J Med Chem 2009; 52:5896-905. [PMID: 19739675 DOI: 10.1021/jm900282z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The non-nucleoside reverse transcriptase inhibitor (NNRTI) TMC278/rilpivirine is an anti-AIDS therapeutic agent with high oral bioavailability despite its high hydrophobicity. Previous studies established a correlation between ability of the drug molecule to form stable, homogeneous populations of spherical nanoparticles (approximately 100-120 nm in diameter) at low pH in surfactant-independent fashion and good oral bioavailability. Here, we hypothesize that the drug is able to assume surfactant-like properties under physiologically relevant conditions, thus facilitating formation of nanostructures in the absence of other surfactants. The results of all-atom molecular dynamics simulations indeed show that protonated drug molecules behave as surfactants at the water/aggregate interface while neutral drug molecules assist aggregate packing via conformational variability. Our simulation results suggest that amphiphilic behavior at low pH and intrinsic flexibility influence drug aggregation and are believed to play critical roles in the favorable oral bioavailability of hydrophobic drugs.
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