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Armstrong AJ, Apóstolo RFG, McCoy TM, Allen FJ, Doutch J, Cattoz BN, Dowding PJ, Welbourn RJL, Routh AF, Camp PJ. Experimental and simulation study of self-assembly and adsorption of glycerol monooleate in n-dodecane with varying water content onto iron oxide. NANOSCALE 2024; 16:1952-1970. [PMID: 38175178 DOI: 10.1039/d3nr05080g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The self-assembly and surface adsorption of glycerol monooleate (GMO) in n-dodecane are studied using a combination of experimental and molecular dynamics simulation techniques. The self-assembly of GMO to form reverse micelles, with and without added water, is studied using small-angle neutron scattering and simulations. A large-scale simulation is also used to investigate the self-assembly kinetics. GMO adsorption onto iron oxide is studied using depletion isotherms, neutron reflectometry, and simulations. The adsorbed amounts of GMO, and any added water, are determined experimentally, and the structures of the adsorbed films are investigated using reflectometry. Detailed fitting and analysis of the reflectometry measurements are presented, taking into account various factors such as surface roughness, and the presence of impurities. The reflectometry measurements are complemented by molecular dynamics simulations, and good consistency between both approaches is demonstrated by direct comparison of measured and simulated reflectivity and scattering length density profiles. The results of this analysis are that in dry systems, GMO adsorbs as self-assembled reverse micelles with some molecules adsorbing directly to the surface through the polar head groups, while in wet systems, the GMO is adsorbed onto a thin layer of water. Only at high surface coverage is some water trapped inside a reverse-micelle structure; at lower surface coverages, the GMO molecules associate primarily with the water layer, rather than self-assemble.
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Affiliation(s)
- Alexander J Armstrong
- ISIS Neutron and Muon Source, Didcot, UK
- Institute for Energy & Environmental Flows and Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Rui F G Apóstolo
- EPCC, Bayes Centre, 47 Potterrow, Edinburgh EH8 9BT, Scotland, UK
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, UK.
| | - Thomas M McCoy
- Institute for Energy & Environmental Flows and Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | | | | | | | | | | | - Alexander F Routh
- Institute for Energy & Environmental Flows and Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Philip J Camp
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, UK.
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Earnden L, Marangoni AG, Laredo T, Stobbs J, Pensini E. Self-Assembled glycerol monooleate demixes miscible liquids through selective hydrogen bonding to water. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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3
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Movchan TG, Rusanov AI, Plotnikova EV. Reverse Micelles and Protomicelles of Tetraethylene Glycol Monododecyl Ether in Systems with Heptane and Nile Red. RUSS J GEN CHEM+ 2022. [DOI: 10.1134/s1070363222040065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Shchekin AK, Adzhemyan LT, Eroshkin YA, Volkov NA. Work of Formation of Direct and Inverse Micelle as a Functions of Aggregation Number. COLLOID JOURNAL 2022. [DOI: 10.1134/s1061933x22010124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Acero PN, Mohr S, Bernabei M, Fernández C, Domínguez B, Ewen JP. Molecular Simulations of Surfactant Adsorption on Iron Oxide from Hydrocarbon Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14582-14596. [PMID: 34878282 DOI: 10.1021/acs.langmuir.1c02133] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The performance of organic friction modifiers (OFMs) depends on their ability to adsorb onto surfaces and form protective monolayers. Understanding the relationship between OFM concentration in the base oil and the resulting surface coverage is important for improving lubricant formulations. Here, we use molecular dynamics (MD) simulations to study the adsorption of three OFMs─stearic acid (SA), glycerol monoostearate (GMS), and glycerol monooleate (GMO)─onto a hematite surface from two hydrocarbon solvents─n-hexadecane and poly(α-olefin) (PAO). We calculate the potential of mean force of the adsorption process using the adaptive biasing force algorithm, and the adsorption strength increases in the order SA < GMS < GMO. We estimate the minimum area occupied by OFM molecules on the surface using annealing MD simulations and obtained a similar hard-disk area for GMS and GMO but a lower value for SA. Using the MD results, we determine the adsorption isotherms using the molecular thermodynamic theory (MTT), which agree well with one previous experimental data set for SA on hematite. For two other experimental data sets for SA, lateral interactions between surfactant molecules need to be accounted for within the MTT framework. SA forms monolayers with lower surface coverage than GMO and GMS at low concentrations but also has the highest plateau coverage. We validate the adsorption energies from the MD simulations using high-frequency reciprocating rig friction experiments with different concentrations of the OFMs in PAO. For OFMs with saturated tailgroups (SA and GMS), we obtain good agreement between the simulations and the experiments. The results deviate for OFMs containing Z-unsaturated tailgroups (GMO) due to the additional steric hindrance, which is not accounted for in the current simulation framework. This study demonstrates that MD simulations, alongside MTT, are an accurate and efficient tool to predict adsorption isotherms at solid-liquid interfaces.
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Affiliation(s)
- Pablo Navarro Acero
- Nextmol (Bytelab Solutions SL), Carrer de Roc Boronat 117, 08 018 Barcelona, Spain
- Barcelona Supercomputing Center (BSC-CNS), Plaça Eusebi Güell, 1-3, 08 034 Barcelona, Spain
| | - Stephan Mohr
- Nextmol (Bytelab Solutions SL), Carrer de Roc Boronat 117, 08 018 Barcelona, Spain
- Barcelona Supercomputing Center (BSC-CNS), Plaça Eusebi Güell, 1-3, 08 034 Barcelona, Spain
| | - Marco Bernabei
- Repsol Technology Lab, DC Technology & Corporate Venturing, Agustín de Betancourt s/n, 28 935 Mostoles, Madrid, Spain
| | - Carlos Fernández
- Repsol Technology Lab, DC Technology & Corporate Venturing, Agustín de Betancourt s/n, 28 935 Mostoles, Madrid, Spain
| | - Beatriz Domínguez
- Repsol Technology Lab, DC Technology & Corporate Venturing, Agustín de Betancourt s/n, 28 935 Mostoles, Madrid, Spain
| | - James P Ewen
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
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Kitaoka M, Nguyen TC, Goto M. Water-in-oil microemulsions composed of monoolein enhanced the transdermal delivery of nicotinamide. Int J Cosmet Sci 2021; 43:302-310. [PMID: 33566391 DOI: 10.1111/ics.12695] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/26/2021] [Accepted: 02/08/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Nicotinamide, also known as niacinamide, is a water-soluble vitamin that is used to prevent and treat acne and pellagra. It is often found in water-based skin care cosmetics because of its high water solubility. Nicotinamide is a small molecule with a molar mass of 122.1 g/mol. However, it has a hydrophilic nature that becomes an obstacle when it penetrates through the skin. The topmost layer of the skin, the stratum corneum, acts as a strong hydrophobic barrier for such hydrophilic molecules. The oil-based formulations are expected to enhance the transdermal delivery efficiency of nicotinamide. METHODS We have developed oil-based microemulsion formulations composed of a squalane vehicle. Monoolein was used as an emulsifier that has a potential to enhance the nicotinamide delivery through the stratum corneum. RESULTS Because the mean size of the emulsions measured by dynamic light scattering was 20.9 ± 0.4 nm, the microemulsion formulation was stable under the long-term storage. Monoolein acted as a skin penetration enhancer, and it effectively enabled the penetration of nicotinamide through human abdominal skin, compared with nicotinamide in a phosphate-buffered saline solution. The flux was increased 25-fold. Microscopic imaging revealed that the hydrophilic bioactive compounds penetrated through the intercellular spaces in the epidermis. CONCLUSION The monoolein-based microemulsion was transparent and stable, suggesting that it is a promising formulation for a transdermal nicotinamide delivery.
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Affiliation(s)
- Momoko Kitaoka
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan
| | - Trung Cong Nguyen
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan
| | - Masahiro Goto
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan.,Center for Future Chemistry, Kyushu University, Fukuoka, Japan.,Advanced Transdermal Drug Delivery System Center, Kyushu University, Fukuoka, Japan
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Innocenti Malini R, Zabara M, Gontsarik M, Maniura-Weber K, Rossi RM, Spano F, Salentinig S. Self-assembly of glycerol monooleate with the antimicrobial peptide LL-37: a molecular dynamics study. RSC Adv 2020; 10:8291-8302. [PMID: 35497861 PMCID: PMC9049931 DOI: 10.1039/c9ra10037g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/04/2020] [Indexed: 11/21/2022] Open
Abstract
Over the past decade, the rapid increase in the incidence of antibiotic-resistant bacteria has promoted research towards alternative therapeutics such as antimicrobial peptides (AMPs), but their biodegradability limits their application. Encapsulation into nanocarriers based on the self-assembly of surfactant-like lipids is emerging as a promising strategy for the improvement of AMPs' stability and their protection against degradation when in biological media. An in-depth understanding of the interactions between the structure-forming lipids and AMPs is required for the design of nanocarriers. This in silico study, demonstrates the self-assembly of the amphiphilic lipid glycerol monooleate (GMO) with the antimicrobial peptide LL-37 into nanocarriers on the molecular scale. Molecular dynamics (MD) simulations show the formation of direct micelles, with either one or two interacting LL-37, and vesicles in this two-component system in agreement with experimental results from small-angle X-ray scattering studies. The hydrophobic contacts between LL-37 and GMOs in water appear responsible for the formation of these nanoparticles. The results also suggest that the enhanced antimicrobial efficiency of LL-37 in these nanocarriers that was previously observed experimentally can be explained by the availability of its side chains with charged amino acids, an increase of the electrostatic interaction and a decrease of the peptide's conformational entropy upon interacting with GMO. The results of this study contribute to the fundamental understanding of lipid-AMP interactions and may guide the comprehensive design of lipid-based self-assembled nanocarriers for antimicrobial peptides.
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Affiliation(s)
- R Innocenti Malini
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - M Zabara
- Laboratory for Biointerfaces, Department Materials meet Life Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - M Gontsarik
- Laboratory for Biointerfaces, Department Materials meet Life Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - K Maniura-Weber
- Laboratory for Biointerfaces, Department Materials meet Life Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - R M Rossi
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - F Spano
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - S Salentinig
- Laboratory for Biointerfaces, Department Materials meet Life Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
- Department of Chemistry, University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
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Tsagkaropoulou G, Warrens CP, Camp PJ. Interactions between Friction Modifiers and Dispersants in Lubricants: The Case of Glycerol Monooleate and Polyisobutylsuccinimide-Polyamine. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28359-28369. [PMID: 31287656 DOI: 10.1021/acsami.9b05718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The structural and frictional properties of 10 wt % solutions of the amphiphilic molecules glycerol monooleate (GMO) and polyisobutylsuccinimide-polyamine (PIBSA-PAM) in squalane are studied using molecular dynamics simulations in bulk and under confinement between iron oxide surfaces. GMO is a friction modifier, PIBSA-PAM is a dispersant, and squalane is a good model for typical base oils. A range of liquid compositions and applied pressures is explored, and the formation and stability of reverse micelles are determined under quiescent and shear conditions. Micellization is observed mainly in systems with a high GMO content, but PIBSA-PAM may also form small aggregates on its own. In the confined systems under both static and shear conditions, some surfactant molecules adsorb onto the surfaces, with the rest of the molecules forming micelles or aggregates. Shearing the liquid layer under high pressure causes almost all of the micelles and aggregates to break, except in systems with around 7.5 wt % GMO and 2.5 wt % PIBSA-PAM. The presence of micelles and adsorbed surfactants is found to be correlated with a low kinetic friction coefficient, and hence, there is an optimum composition range for friction reduction. This work highlights the importance of cooperative interactions between lubricant additives.
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Affiliation(s)
- Georgia Tsagkaropoulou
- School of Chemistry , University of Edinburgh , David Brewster Road , Edinburgh EH9 3FJ , Scotland
| | - Chris P Warrens
- Research and Technology Fuels and Lubricants , BP International Limited, Technology Centre , Whitchurch Hill, Pangbourne, Reading RG8 7QR , England
| | - Philip J Camp
- School of Chemistry , University of Edinburgh , David Brewster Road , Edinburgh EH9 3FJ , Scotland
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Kopanichuk IV, Vedenchuk EA, Koneva AS, Vanin AA. Structural Properties of Span 80/Tween 80 Reverse Micelles by Molecular Dynamics Simulations. J Phys Chem B 2018; 122:8047-8055. [DOI: 10.1021/acs.jpcb.8b03945] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ilia V. Kopanichuk
- Institute of Chemistry, St. Petersburg State University, 7-9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Ekaterina A. Vedenchuk
- Institute of Chemistry, St. Petersburg State University, 7-9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Alina S. Koneva
- Institute of Chemistry, St. Petersburg State University, 7-9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Aleksandr A. Vanin
- Institute of Chemistry, St. Petersburg State University, 7-9 Universitetskaya nab., St. Petersburg 199034, Russia
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Bradley-Shaw JL, Camp PJ, Dowding PJ, Lewtas K. Self-assembly and friction of glycerol monooleate and its hydrolysis products in bulk and confined non-aqueous solvents. Phys Chem Chem Phys 2018; 20:17648-17657. [DOI: 10.1039/c8cp01785a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Molecular dynamics simulations are used to study the interplay between self-assembly, adsorption, and friction in solutions of amphiphilic additives dissolved in non-aqueous solvents.
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Affiliation(s)
| | - Philip J. Camp
- School of Chemistry
- University of Edinburgh
- Edinburgh EH9 3FJ
- UK
| | | | - Ken Lewtas
- School of Chemistry
- University of Edinburgh
- Edinburgh EH9 3FJ
- UK
- Lewtas Science & Technologies
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Vierros S, Österberg M, Sammalkorpi M. Aggregation response of triglyceride hydrolysis products in cyclohexane and triolein. Phys Chem Chem Phys 2018; 20:27192-27204. [DOI: 10.1039/c8cp05104f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aggregation mechanism and the existence of cmc depend on apolar solvent quality and surfactant head group polarity.
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Affiliation(s)
- Sampsa Vierros
- Department of Chemistry and Materials Science
- Aalto University
- 00076 Aalto
- Finland
| | - Monika Österberg
- Department of Bioproducts and Biotechnology
- Aalto University
- 00076 Aalto
- Finland
| | - Maria Sammalkorpi
- Department of Chemistry and Materials Science
- Aalto University
- 00076 Aalto
- Finland
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Chatzidaki MD, Papavasileiou KD, Papadopoulos MG, Xenakis A. Reverse Micelles As Antioxidant Carriers: An Experimental and Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5077-5085. [PMID: 28481539 DOI: 10.1021/acs.langmuir.7b00213] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water-in-oil microemulsions with biocompatible components were formulated to be used as carriers of natural antioxidants, such as hydroxytyrosol (HT) and gallic acid (GA). The system was composed of a mixture of natural surfactants, lecithin and monoglycerides, medium chain triglycerides, and aqueous phase. A dual approach was undertaken to study the structure and dynamics of these complicated systems. First, experimental data were collected by using adequate techniques, such as dynamic light scattering (DLS) and electron paramagnetic resonance (EPR) spectroscopy. Following this, a coarse-grained molecular dynamics (CGMD) study based on the experimental composition using the MARTINI force field was conducted. The simulations revealed the spontaneous formation of reverse micelles (RMs) starting from completely random initial conformations, underlying their enhanced thermodynamic stability. The location of the bioactive molecules, as well as the structure of the RM, were in accordance with the experimental findings. Furthermore, GA molecules were found to be located inside the water core, in contrast to the HT ones, which seem to lie at the surfactant interfacial layer. The difference in the antioxidants' molecular location was only revealed in detail from the computational analysis and explains the RM's swelling observed by GA in DLS measurements.
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Affiliation(s)
- Maria D Chatzidaki
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation , 116 35 Athens, Greece
| | - Konstantinos D Papavasileiou
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation , 116 35 Athens, Greece
- National Center for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology , Aghia Paraskevi Attikis, 153 10 Athens, Greece
| | - Manthos G Papadopoulos
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation , 116 35 Athens, Greece
| | - Aristotelis Xenakis
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation , 116 35 Athens, Greece
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Yuan R, Yan C, Nishida J, Fayer MD. Dynamics in a Water Interfacial Boundary Layer Investigated with IR Polarization-Selective Pump–Probe Experiments. J Phys Chem B 2017; 121:4530-4537. [DOI: 10.1021/acs.jpcb.7b01028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Rongfeng Yuan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Chang Yan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jun Nishida
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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Bradley-Shaw JL, Camp PJ, Dowding PJ, Lewtas K. Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7707-7718. [PMID: 27429247 DOI: 10.1021/acs.langmuir.6b00091] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of the fluid is characterized in various ways, and the differences between systems with nonaggregated GMO and with preformed GMO reverse micelles are examined. Preformed reverse micelles are metastable under static conditions in all systems. In n-heptane under shear conditions, with or without water, preformed GMO reverse micelles remain intact and adsorb onto one surface or another, becoming surface micelles. In dry toluene, preformed reverse micelles break apart under shear, while in the presence of water, the reverse micelles survive and become surface micelles. In all systems under static and shear conditions, nonaggregated GMO adsorbs onto both surfaces with roughly equal probability. Added water is strongly associated with the GMO, irrespective of shear or the form of the added GMO. In all cases, with increasing shear rate, the GMO molecules flatten on the surface, and the kinetic friction coefficient increases. Under low-shear conditions, the friction is insensitive to the form of the GMO added, whereas the presence of water is found to lead to a small reduction in friction. Under high-shear conditions, the presence of reverse micelles leads to a significant reduction in friction, whereas the presence of water increases the friction in n-heptane and decreases the friction in toluene.
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Affiliation(s)
- Joshua L Bradley-Shaw
- School of Chemistry, University of Edinburgh , David Brewster Road, Edinburgh EH9 3FJ, Scotland
| | - Philip J Camp
- School of Chemistry, University of Edinburgh , David Brewster Road, Edinburgh EH9 3FJ, Scotland
| | - Peter J Dowding
- Infineum UK Ltd., P.O. Box 1, Milton Hill, Abingdon OX13 6BB, U.K
| | - Ken Lewtas
- School of Chemistry, University of Edinburgh , David Brewster Road, Edinburgh EH9 3FJ, Scotland
- Lewtas Science & Technologies, 246 Banbury Road, Oxford OX2 7DY, U.K
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