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Heisler IA, Meech SR. Altered relaxation dynamics of excited state reactions by confinement in reverse micelles probed by ultrafast fluorescence up-conversion. Chem Soc Rev 2021; 50:11486-11502. [PMID: 34661209 DOI: 10.1039/d1cs00516b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Chemical reactions in confined environments are important in areas as diverse as heterogenous catalysis, environmental chemistry and biochemistry, yet they are much less well understood than the equivalent reactions in either the gas phase or in free solution. The understanding of chemical reactions in solution was greatly enhanced by real time studies of model reactions, through ultrafast spectroscopy (especially when supported by molecular dynamics simulation). Here we review some of the efforts that have been made to adapt this approach to the investigation of reactions in confined media. Specifically, we review the application of ultrafast fluorescence spectroscopy to measure reaction dynamics in the nanoconfined water phase of reverse micelles, as a function of the droplet radius and the charge on the interface. Methods of measurement and modelling of the reactions are outlined. In all of the cases studied (which are focused on ultrafast intramolecular reactions) the effect of confinement was to suppress the reaction. Even in the largest micelles the result in the bulk aqueous phase was not usually recovered, suggesting an important role for specific interactions between reactant and environment, for example at the interface. There was no simple one-to-one correspondence with direct measures of the dynamics of the confined phase. Thus, understanding the effect of confinement on reaction rate appears to require not only knowledge of the dynamics of the reaction in solutions and the effect of confinement on the medium, but also of the interaction between reactant and confining medium.
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Affiliation(s)
- Ismael A Heisler
- Departamento de Física, Universidade Federal do Paraná, Curitiba, Paraná, CEP 81531-980, Brazil
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, UK.
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2
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Gradzielski M, Duvail M, de Molina PM, Simon M, Talmon Y, Zemb T. Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure. Chem Rev 2021; 121:5671-5740. [PMID: 33955731 DOI: 10.1021/acs.chemrev.0c00812] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Microemulsions, as thermodynamically stable mixtures of oil, water, and surfactant, are known and have been studied for more than 70 years. However, even today there are still quite a number of unclear aspects, and more recent research work has modified and extended our picture. This review gives a short overview of how the understanding of microemulsions has developed, the current view on their properties and structural features, and in particular, how they are related to applications. We also discuss more recent developments regarding nonclassical microemulsions such as surfactant-free (ultraflexible) microemulsions or ones containing uncommon solvents or amphiphiles (like antagonistic salts). These new findings challenge to some extent our previous understanding of microemulsions, which therefore has to be extended to look at the different types of microemulsions in a unified way. In particular, the flexibility of the amphiphilic film is the key property to classify different microemulsion types and their properties in this review. Such a classification of microemulsions requires a thorough determination of their structural properties, and therefore, the experimental methods to determine microemulsion structure and dynamics are reviewed briefly, with a particular emphasis on recent developments in the field of direct imaging by means of electron microscopy. Based on this classification of microemulsions, we then discuss their applications, where the application demands have to be met by the properties of the microemulsion, which in turn are controlled by the flexibility of their amphiphilic interface. Another frequently important aspect for applications is the control of the rheological properties. Normally, microemulsions are low viscous and therefore enhancing viscosity has to be achieved by either having high concentrations (often not wished for) or additives, which do not significantly interfere with the microemulsion. Accordingly, this review gives a comprehensive account of the properties of microemulsions, including most recent developments and bringing them together from a united viewpoint, with an emphasis on how this affects the way of formulating microemulsions for a given application with desired properties.
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Affiliation(s)
- Michael Gradzielski
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Magali Duvail
- ICSM, Université Montpellier, CEA, CNRS, ENSCM, 30207 Marcoule, France
| | - Paula Malo de Molina
- Centro de Física de Materiales (CFM) (CSIC-UPV/EHU)-Materials Physics Center (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.,IKERBASQUE - Basque Foundation for Science, María Díaz de Haro 3, 48013 Bilbao, Spain
| | - Miriam Simon
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, D-10623 Berlin, Germany.,Department of Chemical Engineering and the Russell Berrie Nanotechnolgy Inst. (RBNI), Technion-Israel Institute of Technology, Haifa, IL-3200003, Israel
| | - Yeshayahu Talmon
- Department of Chemical Engineering and the Russell Berrie Nanotechnolgy Inst. (RBNI), Technion-Israel Institute of Technology, Haifa, IL-3200003, Israel
| | - Thomas Zemb
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, D-10623 Berlin, Germany.,ICSM, Université Montpellier, CEA, CNRS, ENSCM, 30207 Marcoule, France
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3
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Mayoral E, Arcos-Casarrubias J, Gama Goicochea A. Self – assembly of model surfactants as reverse micelles in nonpolar solvents and their role as interfacial tension modifiers. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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4
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Shim Y. Computer simulation study of fluorocarbon phosphate surfactant based aqueous reverse micelle in supercritical CO 2: roles of surfactant functional groups, ionic strength, and phase changes in CO 2. Phys Chem Chem Phys 2020; 22:3434-3445. [PMID: 31984986 DOI: 10.1039/c9cp06613f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Structural and dynamic properties of an aqueous micelle organized from fluorocarbon phosphate surfactant molecules in supercritical carbon dioxide (CO2) are investigated via molecular dynamics computer simulations. The roles of the functional groups and ionic strength of the surfactants on the formation of reverse micelles in supercritical CO2, and related water dynamics characterized as translational and reorientational dynamics, are systematically demonstrated by employing three different phosphate-based surfactants paired with sodium cations. The strong electrostatic interactions between the phosphate head groups and sodium cations result in formation of an aqueous core inside the surfactant aggregates, where water molecules are bonded together with loss of the tetrahedral hydrogen bonded network found in bulk water. It is found that all the three surfactants with CO2-philic fluorocarbon double tails build up well-stabilized reverse micelles in supercritical CO2, avoiding direct contacts between CO2 and water molecules. Despite this, the surfactant with a carboxylic ester linkage between the phosphate head and fluorocarbon tail group tends to coordinate water molecules toward sustaining the inter-water hydrogen bonds, indicating better efficiency at covering the aqueous core with hydrophobic groups compared to one without a carboxylic ester group. As for water molecules confined in the reverse micelle, their translational and reorientational motions, and fluctuating dynamics of the inter-water hydrogen bonds, significantly slow down compared to bulk water at ambient temperature. The water dynamics become more restricted with an increase in ionic strength of the anionic surfactant; this is attributed to divalent surfactant heads and sodium cations being more tightly bound together with bonding to water compared to monovalent ones. Lastly, the structural and dynamic changes of the reverse micelle caused by a phase change in CO2 are monitored with gradually decreasing temperature and pressure from the supercritical to gaseous state for CO2. The average reverse micelle structure equilibrated in supercritical CO2 is found to remain stable over a time period of 0.2 ms through a depressurization process to gaseous CO2. We note that the diverse pathways of surfactant self-aggregation in gaseous CO2 could be controlled by the preceding solvation procedure in the supercritical regime which governs the final aggregated structures in gaseous CO2.
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Affiliation(s)
- Youngseon Shim
- CAE Group, Autonomous Material Development Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Gyeonggi 16678, Korea.
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5
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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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6
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Photoisomerization induced scission of rod-like micelles unravelled with multiscale modeling. J Colloid Interface Sci 2018; 510:357-367. [DOI: 10.1016/j.jcis.2017.09.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 09/07/2017] [Accepted: 09/07/2017] [Indexed: 11/21/2022]
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7
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Ingrosso F, Ruiz-López MF. Modeling Solvation in Supercritical CO 2. Chemphyschem 2017; 18:2560-2572. [PMID: 28719104 DOI: 10.1002/cphc.201700434] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Indexed: 11/10/2022]
Abstract
In recent decades, a microscopic understanding of solute-solvent intermolecular interactions has been key to advances in technologies based on supercritical carbon dioxide. In many cases, computational work has provided the impetus for new discoveries, shedding new light on important concepts such as the local structure around the solute in the supercritical medium, the influence of the peculiar properties of the latter on the molecular behavior of dissolved substances and, importantly, CO2 -philicity. In this Review, the theoretical work that has been relevant to these developments is surveyed and, by presenting some crucial open questions, the possible routes to achieving further progress based on the interplay between theory and experiments is discussed.
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Affiliation(s)
- Francesca Ingrosso
- SRSMC UMR 7565, Université de Lorraine, BP 70239, 54506, Vandoeuvre-lès-Nancy, France.,SRSMC UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
| | - Manuel F Ruiz-López
- SRSMC UMR 7565, Université de Lorraine, BP 70239, 54506, Vandoeuvre-lès-Nancy, France.,SRSMC UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
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8
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9
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Liu B, Tang X, Fang W, Li X, Zhang J, Zhang Z, Shen Y, Yan Y, Sun X, He J. Molecular dynamics study of di-CF4 based reverse micelles in supercritical CO 2. Phys Chem Chem Phys 2016; 18:29156-29163. [PMID: 27730238 DOI: 10.1039/c6cp04253h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reverse micelles (RMs) in supercritical CO2 (scCO2) are promising alternatives for organic solvents, especially when both polar and non-polar components are involved. Fluorinated surfactants, particularly double-chain fluorocarbon surfactants, are able to form well-structured RMs in scCO2. The inherent self-assembly mechanisms of surfactants in scCO2 are still subject to discussion. In this study, molecular dynamics simulations are performed to investigate the self-aggregation behavior of di-CF4 based RMs in scCO2, and stable and spherical RMs are formed. The dynamics process and the self-assembly structure in the RMs reveal a three-step mechanism to form the RMs, that is, small RMs, rod-like RMs and fusion of the rod-like RMs. Hydrogen-bonds between headgroups and water molecules, and salt bridges linking Na+ ions, headgroups and water molecules enhance the interfacial packing efficiency of the surfactant. The results show that di-CF4 molecules have a high surfactant coverage at the RM interface, implying a high CO2-philicity. This mainly results from bending of the short chain (C-COO-CH2-(CF2)3-CF3) due to the flexible carboxyl group. The microscopic insight provided in this study is helpful in understanding surfactant self-assembly phenomena and designing new CO2-philic surfactants.
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Affiliation(s)
- Bing Liu
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China. and NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
| | - Xinpeng Tang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Wenjing Fang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Xiaoqi Li
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Jun Zhang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Zhiliang Zhang
- NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
| | - Yue Shen
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Youguo Yan
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Xiaoli Sun
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Jianying He
- NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
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10
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Ghelichi M, Qazvini NT. Self-organization of hydrophobic-capped triblock copolymers with a polyelectrolyte midblock: a coarse-grained molecular dynamics simulation study. SOFT MATTER 2016; 12:4611-4620. [PMID: 27116478 DOI: 10.1039/c6sm00414h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present the results of a Langevin dynamics simulation study of micellar organization and hydrogel formation in the solutions of coarse-grained ABA copolymer chains. Polymer chains are modeled as bead-spring chains of Lennard-Jones particles by explicit treatment of ionic species in implicit solvent. The studied copolymer is composed of a polyelectrolyte midblock flanked by two hydrophobic endblocks. We explore the self-assembly of copolymer solutions at a fixed polymer concentration and temperature upon systematic variation of the midblock charge fraction, valency of neutralizing counterions, and the stiffness and length of hydrophobic endblocks. Minimization of the surface energy, conformational entropy of the midblock chains, electrostatic repulsion of midblock charges, and the translational entropy of counterions are found to play central roles in controlling the self-organization features of copolymer solutions. Flower-like micelles with A-blocks forming the core of spherical aggregates and B-blocks constituting the micelle corona are established for the neutral midblocks. Increasing the charge content of B chains lowers the fraction of loop conformations and yields a spanning hydrogel network with midblocks bridging the hydrophobic clusters. Counterion valence is shown to exert a strong effect on the micelle size and network structure. The increase in the rigidity of terminal A-blocks increases the fraction of bridging chains and results in the formation of a hydrogel network with bundle-like hydrophobic domains. Longer endblocks are shown to increase the hydrophobic cluster size and enhance the bridged midblock fraction. The qualitative agreement between the experimental and theoretical studies is also discussed. The comprehensive molecular picture provides a framework for the future studies of stimuli-responsive copolymer systems.
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Affiliation(s)
- Mahdi Ghelichi
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
| | - Nader Taheri Qazvini
- Polymer Division, School of Chemistry, College of Science, University of Tehran, P. O. Box 14155-6455, Tehran, Iran and Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
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12
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Mudzhikova GV, Brodskaya EN. An AOT reverse micelle in a medium of supercritical carbon dioxide. COLLOID JOURNAL 2015. [DOI: 10.1134/s1061933x15030126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Nevidimov AV. Molecular dynamics simulation of reverse micelles: Standing problems after 25 years of research. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2014. [DOI: 10.1134/s199079311404023x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Zhang J, Peng L, Han B. Amphiphile self-assemblies in supercritical CO2 and ionic liquids. SOFT MATTER 2014; 10:5861-5868. [PMID: 25000970 DOI: 10.1039/c4sm00890a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Supercritical (sc) CO2 and ionic liquids (ILs) are very attractive green solvents with tunable properties. Using scCO2 and ILs as alternatives of conventional solvents (water and oil) for forming amphiphile self-assemblies has many advantages. For example, the properties and structures of the amphiphile self-assemblies in these solvents can be easily modulated by tuning the properties of solvents; scCO2 has excellent solvation power and mass-transfer characteristics; ILs can dissolve both organic and inorganic substances and their properties are designable to satisfy the requirements of various applications. Therefore, the amphiphile self-assemblies in scCO2 and ILs have attracted considerable attention in recent years. This review describes the advances of using scCO2 or/and ILs as amphiphile self-assembly media in the last decade. The amphiphile self-assemblies in scCO2 and ILs are first reviewed, followed by the discussion on combination of scCO2 and ILs in creating microemulsions or emulsions. Some future directions on the amphiphile self-assemblies in scCO2 and ILs are highlighted.
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Affiliation(s)
- Jianling Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, China.
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15
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Yan M, Yang X, Lu Y. Wetting behavior of water droplet on solid surfaces in solvent environment: A molecular simulation study. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.03.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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16
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Sagisaka M, Iwama S, Ono S, Yoshizawa A, Mohamed A, Cummings S, Yan C, James C, Rogers SE, Heenan RK, Eastoe J. Nanostructures in water-in-CO2 microemulsions stabilized by double-chain fluorocarbon solubilizers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7618-7628. [PMID: 23701401 DOI: 10.1021/la400376g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
High-pressure small-angle neutron scattering (HP-SANS) studies were conducted to investigate nanostructures and interfacial properties of water-in-supercritical CO2 (W/CO2) microemulsions with double-fluorocarbon-tail anionic surfactants, having different fluorocarbon chain lengths and linking groups (glutarate or succinate). At constant pressure and temperature, the microemulsion aqueous cores were found to swell with an increase in water-to-surfactant ratio, W0, until their solubilizing capacities were reached. Surfactants with fluorocarbon chain lengths of n = 4, 6, and 8 formed spherical reversed micelles in supercritical CO2 even at W0 over the solubilizing powers as determined by phase behavior studies, suggesting formation of Winsor-IV W/CO2 microemulsions and then Winsor-II W/CO2 microemulsions. On the other hand, a short C2 chain fluorocarbon surfactant analogue displayed a transition from Winsor-IV microemulsions to lamellar liquid crystals at W0 = 25. Critical packing parameters and aggregation numbers were calculated by using area per headgroup, shell thickness, the core/shell radii determined from SANS data analysis: these parameters were used to help understand differences in aggregation behavior and solubilizing power in CO2. Increasing the microemulsion water loading led the critical packing parameter to decrease to ~1.3 and the aggregation number to increase to >90. Although these parameters were comparable between glutarate and succinate surfactants with the same fluorocarbon chain, decreasing the fluorocarbon chain length n reduced the critical packing parameter. At the same time, reducing chain length to 2 reduced negative interfacial curvature, favoring planar structures, as demonstrated by generation of lamellar liquid crystal phases.
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Affiliation(s)
- Masanobu Sagisaka
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japan.
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Correa NM, Silber JJ, Riter RE, Levinger NE. Nonaqueous Polar Solvents in Reverse Micelle Systems. Chem Rev 2012; 112:4569-602. [DOI: 10.1021/cr200254q] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- N. Mariano Correa
- Departamento de Química, Universidad Nacional de Río Cuarto, Agencia
Postal #3, C.P. X5804BYA Río Cuarto, Argentina
| | - Juana J. Silber
- Departamento de Química, Universidad Nacional de Río Cuarto, Agencia
Postal #3, C.P. X5804BYA Río Cuarto, Argentina
| | - Ruth E. Riter
- Department of Chemistry, Agnes Scott College, Decatur, Georgia 30030-3770, United
States
| | - Nancy E. Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
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Mudzhikova GV, Brodskaya EN. Computer simulation of reverse micelles and water-in-oil microemulsions. COLLOID JOURNAL 2012. [DOI: 10.1134/s1061933x1203009x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Mudzhikova GV, Brodskaya EN. Study of mechanism of micellization in nonpolar media. COLLOID JOURNAL 2011. [DOI: 10.1134/s1061933x11050097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Yang Z, Yang X, Xu Z, Yang N. Molecular simulations of structures and solvation free energies of passivated gold nanoparticles in supercritical CO2. J Chem Phys 2010; 133:094702. [DOI: 10.1063/1.3469774] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Wu B, Yang X, Xu Z, Xu Z. Molecular dynamics simulation of self-assembly structure for AOK based reverse micelle in supercritical CO2. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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22
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Chandran A, Prakash K, Senapati S. Self-Assembled Inverted Micelles Stabilize Ionic Liquid Domains in Supercritical CO2. J Am Chem Soc 2010; 132:12511-6. [DOI: 10.1021/ja1055005] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Aneesh Chandran
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, India,
| | - Karthigeyan Prakash
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, India,
| | - Sanjib Senapati
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, India,
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Liu S, Yang X, Qin Y. Molecular dynamics simulation of wetting behavior at CO2/water/solid interfaces. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11434-010-3287-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abel S, Waks M, Marchi M. Molecular dynamics simulations of cytochrome c unfolding in AOT reverse micelles: The first steps. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2010; 32:399-409. [PMID: 20803162 DOI: 10.1140/epje/i2010-10635-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 07/06/2010] [Indexed: 05/29/2023]
Abstract
This paper explores the reduced form of horse cytochrome c confined in reverse micelles (RM) of sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) in isooctane by molecular dynamics simulation. RMs of two sizes were constructed at a water content of W (o) = [ H₂O ]/[AOT] = 5.5 and 9.1. Our results show that the protein secondary structure and the heme conformation both depend on micellar hydration. At low hydration, the protein structure and the heme moiety remain stable, whereas at high water content the protein becomes unstable and starts to unfold. At W (o) = 9.1 , according to the X-ray structure, conformational changes are mainly localized on protein loops and around the heme moiety, where we observe a partial opening of the heme crevice. These findings suggest that within our time window (10ns), the structural changes observed at the heme level are the first steps of the protein denaturation process, previously described experimentally in micellar solutions. In addition, a specific binding of AOT molecules to a few lysine residues of the protein was found only in the small-sized RM.
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Affiliation(s)
- S Abel
- DSV/iBiTecS/SB2SM, CNRS URA, Gif-sur-Yvette, France.
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Du Q, Yang Z, Yang N, Yang X. Coarse-Grained Model for Perfluorocarbons and Phase Equilibrium Simulation of Perfluorocarbons/CO2 Mixtures. Ind Eng Chem Res 2010. [DOI: 10.1021/ie100935u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qiu Du
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
| | - Zhen Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
| | - Nannan Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
| | - Xiaoning Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
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Blakey I, Thurecht KJ, Whittaker AK. High-pressure real-time 129Xe NMR: monitoring of surfactant conformation during the self-assembly of reverse micelles in supercritical carbon dioxide. Chem Commun (Camb) 2010; 46:2850-2. [DOI: 10.1039/b927029a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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27
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Nevidimov AV, Razumov VF. Molecular dynamics simulations of AOT reverse micelles' self-assembly. Mol Phys 2009. [DOI: 10.1080/00268970903203736] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Liu JH, Tsai CY, Chiu YH, Hsieh FM. The fabrication of polycrystalline silver nanowires via self-assembled nanotubes at controlled temperature. NANOTECHNOLOGY 2009; 20:035301. [PMID: 19417290 DOI: 10.1088/0957-4484/20/3/035301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a novel method for the fabrication of silver nanowires under controlled conditions. Silver nanoparticles were synthesized using a surfactant of octanoic acid via a reverse micelle technique. Hollow nanotubes were prepared under various controlled conditions through self-assembly of surfactant clusters of reversed micelles containing silver nanoparticles. These organized nanotubes were used as a structure-directing template for the preparation of silver nanowires. This is a bottom-up technique for the fabrication of silver nanowires. Self-assembled nanotube construction and the cross section of the nanotubes were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. From the results, reasonable schematic representations of the formation of self-assembled nanoparticles and nanowires were proposed. Further sintering treatment at 500 degrees C burned away the organic compounds and left silver nanowires. The construction of the nanowires was confirmed using SEM, x-ray diffraction (XRD), and energy dispersive x-ray analysis (EDXA). This paper demonstrates that silver nanowires can be fabricated via self-assembled nanoparticles at a controlled low temperature.
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Affiliation(s)
- Jui-Hsiang Liu
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China.
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Kondo M, Heisler IA, Conyard J, Rivett JPH, Meech SR. Reactive Dynamics in Confined Liquids: Interfacial Charge Effects on Ultrafast Torsional Dynamics in Water Nanodroplets. J Phys Chem B 2009; 113:1632-9. [DOI: 10.1021/jp808991g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Minako Kondo
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Ismael A. Heisler
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Jamie Conyard
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Jasmine P. H. Rivett
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Stephen R. Meech
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
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Xu Z, Yang X, Yang Z. On the Mechanism of Surfactant Adsorption on Solid Surfaces: Free-Energy Investigations. J Phys Chem B 2008; 112:13802-11. [DOI: 10.1021/jp8055009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhijun Xu
- State Key Laboratory of Material-Orientated Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
| | - Xiaoning Yang
- State Key Laboratory of Material-Orientated Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
| | - Zhen Yang
- State Key Laboratory of Material-Orientated Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
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Liu L, Yang X, Xu Z. Gibbs ensemble Monte Carlo simulation of adsorption for model surfactant solution in confined slit pores. J Chem Phys 2008; 128:184712. [DOI: 10.1063/1.2919556] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Xu Z, Yang X, Yang Z. Adsorption and self-assembly of surfactant/supercritical CO2 systems in confined pores: a molecular dynamics simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:9201-12. [PMID: 17676777 DOI: 10.1021/la7011588] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A coarse-grained molecular dynamics simulation has been carried out to study the adsorption and self-organization for a model surfactant/supercritical CO2 system confined in the slit-shape nanopores with amorphous silica-like surfaces. The solid surfaces were designed to be CO2-philic and CO2-phobic, respectively. For the CO2-philic surface, obviously surface adsorption is observed for the surfactant molecules. The various energy profiles were used to monitor the lengthy dynamics process of the adsorption and self-assembly for surfactant micelles or monomers in the confined spaces. The equilibrium properties, including the morphologies and micelle-size distributions of absorbed surfactants, were evaluated based on the equilibrium trajectory data. The interaction between the surfactant and the surface produces an obvious effect on the dynamics rate of surfactant adsorption and aggregation, as well as the final self-assembly equilibrium structures of the adsorbed surfactants. However, for the CO2-phobic surfaces, there are scarcely adsorption layers of surfactant molecules, meaning that the CO2-phobic surface repels the surfactant molecules. It seems to conclude that the CO2 solvent depletion near the interfaces determines the surface repellence to the surfactant molecules. The effect of the CO2-phobic surface confinement on the surfactant micelle structure in the supercritical CO2 has also been discussed. In summary, this study on the microscopic behaviors of surfactant/Sc-CO2 in confined pores will help to shed light on the surfactant self-assembly from the Sc-CO2 fluid phase onto solid surfaces and nanoporous media.
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Affiliation(s)
- Zhijun Xu
- State Key Laboratory of Material-Orientated Chemical Engineering, Nanjing University of Technology, Nanjing, China
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33
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Choudhury † N, Montgomery Pettitt B. Local density profiles are coupled to solute size and attractive potential for nanoscopic hydrophobic solutes. MOLECULAR SIMULATION 2005. [DOI: 10.1080/08927020500035457] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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