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Gale CD, Derakhshani-Molayousefi M, Levinger NE. Shape of AOT Reverse Micelles: The Mesoscopic Assembly Is More Than the Sum of the Parts. J Phys Chem B 2024. [PMID: 38900154 DOI: 10.1021/acs.jpcb.4c02569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
AOT reverse micelles are a common and convenient model system for studying the effects of nanoconfinement on aqueous solutions. The reverse micelle shape is important to understanding how the constituent components come together to form the coherent whole and the unique properties observed there. The shape of reverse micelles impacts the amount of interface present and the distance of the solute from the interface and is therefore vital to understanding interfacial properties and the behavior of solutes in the polar core. In this work, we use previously introduced measures of shape, the coordinate-pair eccentricity (CPE) and convexity, and apply them to a series of simulations of AOT reverse micelles. We simulate the most commonly used force field for AOT reverse micelles, the CHARMM force field, but we also adapt the OPLS force field for use with AOT, the first work to do so, in addition to using both 3- and 4-site water models. Altogether, these simulations are designed to examine the impact of the force field on the shape of the reverse micelles in detail. We also study the time autocorrelation of shape, the water rotational anisotropy decay, and how the CPE changes between the water pool and AOT tail groups. We find that although the force field changes the shape noticeably, AOT reverse micelles are always amorphous particles. The shape of the micelles changes on the order of 10 ns. The water rotational dynamics observed match the experiment and demonstrate slower dynamics relative to bulk water, suggesting a two-population model that fits a core/shell hypothesis. Taken together, our results indicate that it is likely not possible to create a perfect force field that can reproduce every aspect of the AOT reverse micelle accurately. However, the magnitude of the differences between simulations appears relatively small, suggesting that any reasonably derived force field should provide an acceptable model for most work on AOT reverse micelles.
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Affiliation(s)
- Christopher D Gale
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | | | - Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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2
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Murakami H. Persistent optical hole-burning spectroscopy of nano-confined dye molecules in liquid at room temperature: Spectral narrowing due to a glassy state and extraordinary relaxation in a nano-cage. J Chem Phys 2018; 148:144505. [PMID: 29655335 DOI: 10.1063/1.5008448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Persistent optical hole-burning spectroscopy has been conducted for a dye molecule within a very small (∼1 nm) reverse micelle at room temperature. The spectra show a spectral narrowing due to site-selective excitation. This definitely demonstrates that the surroundings of the dye molecule are in a glassy state regardless of a solution at room temperature. On the other hand, the hole-burning spectra exhibit large shifts from excitation frequencies, and their positions are almost independent of excitation frequencies. The hole-burning spectra have been theoretically calculated by taking account of a vibronic absorption band of the dye molecule under the assumption that the surroundings of the dye molecule are in a glassy state. The calculated results agree with the experimental ones that were obtained for the dye molecule in a polymer glass for comparison, where it has been found that the ratio of hole-burning efficiencies of vibronic- to electronic-band excitations is quite high. On the other hand, the theoretical results do not explain the large spectral shift from the excitation frequency and small spectral narrowing observed in the hole-burning spectra measured for the dye-containing reverse micelle. It is thought that the spectral shift and broadening occur within the measurement time owing to the relaxation process of the surroundings that are hot with the thermal energy deposited by the dye molecule optically excited. Furthermore, the relaxation should be temporary because the cooling of the inside of the reverse micelle takes place with the dissipation of the excess thermal energy to the outer oil solvent, and so the surroundings of the dye molecule return to the glassy state and do not attain the thermal equilibrium. These results suggest that a very small reverse micelle provides a unique reaction field in which the diffusional motion can be controlled by light in a glassy state.
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Affiliation(s)
- Hiroshi Murakami
- QST Advanced Study Laboratory and Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa City, Kyoto 619-0215, Japan
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3
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Chen G, Shrestha R, Amori A, Staniszewski Z, Jukna A, Korliov A, Richter C, El Fray M, Krauss T, Sobolewski R. Terahertz time-domain spectroscopy characterization of carbon nanostructures embedded in polymer. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/906/1/012002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Soylemez E, de Boer MP. Capillary-induced crack healing between surfaces of nanoscale roughness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11625-11633. [PMID: 25195655 DOI: 10.1021/la5026284] [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
Capillary forces are important in nature (granular materials, insect locomotion) and in technology (disk drives, adhesion). Although well studied in equilibrium state, the dynamics of capillary formation merit further investigation. Here, we show that microcantilever crack healing experiments are a viable experimental technique for investigating the influence of capillary nucleation on crack healing between rough surfaces. The average crack healing velocity, v̅, between clean hydrophilic polycrystalline silicon surfaces of nanoscale roughness is measured. A plot of v̅ versus energy release rate, G, reveals log-linear behavior, while the slope |d[log(v̅)]/dG| decreases with increasing relative humidity. A simplified interface model that accounts for the nucleation time of water bridges by an activated process is developed to gain insight into the crack healing trends. This methodology enables us to gain insight into capillary bridge dynamics, with a goal of attaining a predictive capability for this important microelectromechanical systems (MEMS) reliability failure mechanism.
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Affiliation(s)
- Emrecan Soylemez
- Mechanical Engineering Department, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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6
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Murakami H, Sada T, Yamada M, Harada M. Nanometer-scale water droplet free from the constraint of reverse micelles at low temperatures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:052304. [PMID: 24329261 DOI: 10.1103/physreve.88.052304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 07/02/2013] [Indexed: 06/03/2023]
Abstract
Temperature dependence of the configurational fluctuation of water confined in a reverse micellar solution has been studied by absorption spectroscopy of a probe molecule. We have found that the configurational fluctuation is liquidlike below the homogeneous nucleation temperature. This is proposed to be due to a large reduction in the confinement of water, and is explained in terms of water shedding from the reverse micelle. Further, the configurational fluctuation is frozen at ~210 K. A reverse micellar solution is considered to be a promising candidate for studies of supercooled water.
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Affiliation(s)
- H Murakami
- Kansai Photon Science Institute, Japan Atomic Energy Agency, Kyoto 619-0215, Japan
| | - T Sada
- Kansai Photon Science Institute, Japan Atomic Energy Agency, Kyoto 619-0215, Japan and Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan
| | - M Yamada
- Kansai Photon Science Institute, Japan Atomic Energy Agency, Kyoto 619-0215, Japan and Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan
| | - M Harada
- Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan
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7
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Qi W, Chen J, Yang J, Lei X, Song B, Fang H. Anisotropic Dielectric Relaxation of the Water Confined in Nanotubes for Terahertz Spectroscopy Studied by Molecular Dynamics Simulations. J Phys Chem B 2013; 117:7967-71. [PMID: 23751101 DOI: 10.1021/jp3120435] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wenpeng Qi
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
| | - Jige Chen
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
| | - Junwei Yang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
- College of
Physical Science and Technology, Sichuan University, Chengdu 610064, P.R. China
| | - Xiaoling Lei
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
| | - Bo Song
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
| | - Haiping Fang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai
201800, China
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Dowgiallo AM, Knappenberger KL. Influence of Confined Fluids on Nanoparticle-to-Surroundings Energy Transfer. J Am Chem Soc 2012; 134:19393-400. [DOI: 10.1021/ja306644p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Anne-Marie Dowgiallo
- Department
of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4309,
United States
| | - Kenneth L. Knappenberger
- Department
of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4309,
United States
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van der Loop TH, Panman MR, Lotze S, Zhang J, Vad T, Bakker HJ, Sager WFC, Woutersen S. Structure and dynamics of water in nonionic reverse micelles: A combined time-resolved infrared and small angle x-ray scattering study. J Chem Phys 2012; 137:044503. [DOI: 10.1063/1.4736562] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Naceur IB, Guettari M, Kassab G, Tajouri T. Simple-Complex Fluid Transition in Microemulsions. J MACROMOL SCI B 2012. [DOI: 10.1080/00222348.2012.665781] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Imen Ben Naceur
- a Unité de recherche RMN des polymères et des composites, Tunis Preparatory Engineering Institute , University of Tunis , Tunisia
| | - Moez Guettari
- a Unité de recherche RMN des polymères et des composites, Tunis Preparatory Engineering Institute , University of Tunis , Tunisia
| | - Ghazi Kassab
- a Unité de recherche RMN des polymères et des composites, Tunis Preparatory Engineering Institute , University of Tunis , Tunisia
| | - Tahar Tajouri
- a Unité de recherche RMN des polymères et des composites, Tunis Preparatory Engineering Institute , University of Tunis , Tunisia
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11
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Beutel S, Henkel S. In situ sensor techniques in modern bioprocess monitoring. Appl Microbiol Biotechnol 2011; 91:1493-505. [DOI: 10.1007/s00253-011-3470-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/24/2011] [Accepted: 07/10/2011] [Indexed: 12/22/2022]
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12
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Chowdhary J, Ladanyi BM. Molecular simulation study of water mobility in aerosol-OT reverse micelles. J Phys Chem A 2011; 115:6306-16. [PMID: 21548627 DOI: 10.1021/jp201866t] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this work, we present results from molecular dynamics simulations on the single-molecule relaxation of water within reverse micelles (RMs) of different sizes formed by the surfactant aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) in isooctane. Results are presented for RM water content w(0) = [H(2)O]/[AOT] in the range from 2.0 to 7.5. We show that translational diffusion of water within the RM can, to a good approximation, be decoupled from the translation of the RM through the isooctane solvent. Water translational mobility within the RM is restricted by the water pool dimensions, and thus, the water mean-squared displacements (MSDs) level off in time. Comparison with models of diffusion in confined geometries shows that a version of the Gaussian confinement model with a biexponential decay of correlations provides a good fit to the MSDs, while a model of free diffusion within a sphere agrees less well with simulation results. We find that the local diffusivity is considerably reduced in the interfacial region, especially as w(0) decreases. Molecular orientational relaxation is monitored by examining the behavior of OH and dipole vectors. For both vectors, orientational relaxation slows down close to the interface and as w(0) decreases. For the OH vector, reorientation is strongly affected by the presence of charged species at the RM interface and these effects are especially pronounced for water molecules hydrogen-bonded to surfactant sites that serve as hydrogen-bond acceptors. For the dipole vector, orientational relaxation near the interface slows down more than that for the OH vector due mainly to the influence of ion-dipole interactions with the sodium counterions. We investigate water OH and dipole reorientation mechanisms by studying the w(0) and interfacial shell dependence of orientational time correlations for different Legendre polynomial orders.
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Affiliation(s)
- Janamejaya Chowdhary
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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13
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Møller U, Folkenberg JR, Jepsen PU. Dielectric properties of water in butter and water-AOT-heptane systems measured using terahertz time-domain spectroscopy. APPLIED SPECTROSCOPY 2010; 64:1028-1036. [PMID: 20828440 DOI: 10.1366/000370210792434422] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We investigate the dielectric properties of water confined in nanometer-sized inverse micelles in mixtures of water, AOT, and heptane. We show that the dielectric properties of the confined water are dependent on the water pool size and different from those of bulk water. We also discuss the dielectric properties of different vegetable oils, lard, and butter, and use these properties to deduce the dielectric properties of water in butter, which are shown to deviate significantly from the dielectric properties of bulk water.
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Affiliation(s)
- Uffe Møller
- DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Bldg. 343, DK-2800 Kgs. Lyngby, Denmark
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15
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Abstract
Recent advances in ultrafast laser technology have spurred investigations of microheterogeneous solutions. In particular, researchers have explored details of reverse micelles (RMs), which present isolated droplets of polar solvent sequestered from a continuous nonpolar phase by a surfactant layer. This review explores recent studies utilizing a variety of ultrafast laser techniques to uncover details about structure and dynamics in various RMs. Using ultrafast vibrational spectroscopy, researchers have probed hydrogen-bond dynamics and vibrational energy relaxation in RMs. These studies have developed our understanding of reverse micellar structure, identifying varying water environments in the RMs. In a plethora of experiments employing probe molecules, researchers have explored the confined environment presented by RMs and their impact on a range of chemical reactions. These studies have shown that confinement, rather than the specific interactions with surfactants, is an important factor determining the impact of the reverse micellar environment on the chemistry.
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Affiliation(s)
- Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
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17
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Piletic IR, Moilanen DE, Spry DB, Levinger NE, Fayer MD. Testing the Core/Shell Model of Nanoconfined Water in Reverse Micelles Using Linear and Nonlinear IR Spectroscopy. J Phys Chem A 2006; 110:4985-99. [PMID: 16610816 DOI: 10.1021/jp061065c] [Citation(s) in RCA: 269] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A core/shell model has often been used to describe water confined to the interior of reverse micelles. The validity of this model for water encapsulated in AOT/isooctane reverse micelles ranging in diameter from 1.7 to 28 nm (w0 = 2-60) and bulk water is investigated using four experimental observables: the hydroxyl stretch absorption spectra, vibrational population relaxation times, orientational relaxation rates, and spectral diffusion dynamics. The time dependent observables are measured with ultrafast infrared spectrally resolved pump-probe and vibrational echo spectroscopies. Major progressive changes appear in all observables as the system moves from bulk water to the smallest water nanopool, w0 = 2. The dynamics are readily distinguishable for reverse micelle sizes smaller than 7 nm in diameter (w0 = 20) compared to the response of bulk water. The results also demonstrate that the size dependent absorption spectra and population relaxation times can be quantitatively predicted using a core-shell model in which the properties of the core (interior of the nanopool) are taken to be those of bulk water and the properties of the shell (water associated with the headgroups) are taken to be those of w0 = 2. A weighted sum of the core and shell components reproduces the size dependent spectra and the nonexponential population relaxation dynamics. However, the same model does not reproduce the spectral diffusion and the orientational relaxation experiments. It is proposed that, when hydrogen bond structural rearrangement is involved (orientational relaxation and spectral diffusion), dynamical coupling between the shell and the core cause the water nanopool to display more homogeneous dynamics. Therefore, the absorption spectra and vibrational lifetime decays can discern different hydrogen bonding environments whereas orientational and spectral diffusion correlation functions predict that the dynamics are size dependent but not as strongly spatially dependent within a reverse micelle.
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Affiliation(s)
- Ivan R Piletic
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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18
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Shimizu T. Self-assembled lipid nanotube hosts: The dimension control for encapsulation of nanometer-scale guest substances. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21619] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Hunt NT, Jaye AA, Meech SR. Reactive dynamics in confined water droplets: Auramine O in AOT/water/heptane microemulsions. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.09.063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Szoszkiewicz R, Riedo E. Nucleation time of nanoscale water bridges. PHYSICAL REVIEW LETTERS 2005; 95:135502. [PMID: 16197146 DOI: 10.1103/physrevlett.95.135502] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Indexed: 05/04/2023]
Abstract
Water capillaries bind together grains of sand. They also can bind an atomic force microscope tip to a substrate. The kinetics of capillary condensation at the nanoscale is studied here using friction force microscopy. At 40% relative humidity we find that the meniscus nucleation times increase from 0.7 to 4.2 ms when the temperature decreases from 332 to 299 K. The nucleation times grow exponentially with the inverse temperature 1/T obeying an Arrhenius law. We obtain a nucleation energy barrier of 7.8 x 10(-20) J and an attempt frequency ranging between 4 and 250 GHz, in excellent agreement with theoretical predictions. These results provide direct experimental evidence that capillary condensation is a thermally activated phenomenon.
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Affiliation(s)
- Robert Szoszkiewicz
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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21
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Piletic IR, Tan HS, Fayer MD. Dynamics of Nanoscopic Water: Vibrational Echo and Infrared Pump−Probe Studies of Reverse Micelles. J Phys Chem B 2005; 109:21273-84. [PMID: 16853758 DOI: 10.1021/jp051837p] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The dynamics of water in nanoscopic pools 1.7-4.0 nm in diameter in AOT reverse micelles were studied with ultrafast infrared spectrally resolved stimulated vibrational echo and pump-probe spectroscopies. The experiments were conducted on the OD hydroxyl stretch of low-concentration HOD in the H2O, providing a direct examination of the hydrogen-bond network dynamics. Pump-probe experiments show that the vibrational lifetime of the OD stretch mode increases as the size of the reverse micelle decreases. These experiments are also sensitive to hydrogen-bond dissociation and reformation dynamics, which are observed to change with reverse micelle size. Spectrally resolved vibrational echo data were obtained at several frequencies. The vibrational echo data are compared to data taken on bulk water and on a 6 M NaCl solution, which is used to examine the role of ionic strength on the water dynamics in reverse micelles. Two types of vibrational echo measurements are presented: the vibrational echo decays and the vibrational echo peak shifts. As the water nanopool size decreases, the vibrational echo decays become slower. Even the largest nanopool (4 nm, approximately 1000 water molecules) has dynamics that are substantially slower than bulk water. It is demonstrated that the slow dynamics in the reverse micelle water nanopools are a result of confinement rather than ionic strength. The data are fit using time-dependent diagrammatic perturbation theory to obtain the frequency-frequency correlation function (FFCF) for each reverse micelle. The results are compared to the FFCF of water and show that the largest differences are in the slowest time scale dynamics. In bulk water, the slowest time scale dynamics are caused by hydrogen-bond network equilibration, i.e., the making and breaking of hydrogen bonds. For the smallest nanopools, the longest time scale component of the water dynamics is approximately 10 times longer than the dynamics in bulk water. The vibrational echo data for the smallest reverse micelle displays a dependence on the detection wavelength, which may indicate that multiple ensembles of water molecules are being observed.
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Affiliation(s)
- Ivan R Piletic
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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22
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Tan HS, Piletic IR, Fayer MD. Orientational dynamics of water confined on a nanometer length scale in reverse micelles. J Chem Phys 2005; 122:174501. [PMID: 15910039 DOI: 10.1063/1.1883605] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The time-resolved orientational anisotropies of the OD hydroxyl stretch of dilute HOD in H(2)O confined on a nanometer length scale in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles are studied using ultrafast infrared polarization and spectrally resolved pump-probe spectroscopy, and the results are compared to the same experiments on bulk water. The orientational anisotropy data for three water nanopool sizes (4.0, 2.4, and 1.7 nm) can be fitted well with biexponential decays. The biexponential decays are analyzed using a wobbling-in-a-cone model that involves fast orientational diffusion within a cone followed by slower, full orientational relaxation. The data provide the cone angles, the diffusion constants for motion within the cones, and the final diffusion constants as a function of the nanopool size. The two processes can be interpreted as a local angular fluctuation of the OD and a global hydrogen bond network rearrangement process. The trend in the relative amplitudes of the long and short exponential decays suggest an increasing rigidity as the nanopool size decreases. The trend in the long decay constants indicates a longer hydrogen bond network rearrangement time with decreasing reverse micelle size. The anisotropy measurements for the reverse micelles studied extrapolate to approximately 0.33 rather than the ideal value of 0.4, suggesting the presence of an initial inertial component in the anisotropy decay that is too fast to resolve. The very fast decay component is consistent with initial inertial orientational motion that is seen in published molecular-dynamics simulations of water in AOT reverse micelles. The angle over which the inertial orientational motion occurs is determined. The results are in semiquantitative agreement with the molecular-dynamics simulations.
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Affiliation(s)
- Howe-Siang Tan
- Department of Chemistry, Stanford University, California 94305, USA.
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Jaye AA, Hunt NT, Meech SR. Ultrafast dynamics in the dispersed phase of oil-in-water microemulsions: monosubstituted benzenes incorporated into dodecyltrimethylammonium bromide (DTAB) aqueous micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:1238-1243. [PMID: 15697266 DOI: 10.1021/la047599r] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Time-resolved optical Kerr effect spectroscopy has been used to probe the molecular environment afforded by the hydrophobic core of oil-in-water microemulsions. This was achieved by measuring the ultrafast dynamics of a series of benzene derivatives (benzonitrile, nitrobenzene, fluorobenzene, styrene, and toluene) incorporated as the oil phase within oil-in-water microemulsions and comparing them to the dynamics in neat liquid and the liquid diluted in nonpolar solvent. Polar and strongly interacting liquids (benzonitrile and nitrobenzene) showed dynamics in the microemulsion that are similar to those in the solution phase, while weakly interacting and mildly polar liquids (fluorobenzene, styrene and toluene) reveal dynamics more similar to those of the neat liquid. This suggests stabilization of the polar dispersed phase in polar regions of the micelle.
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Affiliation(s)
- Andrew A Jaye
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
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Tan HS, Piletic IR, Riter RE, Levinger NE, Fayer MD. Dynamics of water confined on a nanometer length scale in reverse micelles: ultrafast infrared vibrational echo spectroscopy. PHYSICAL REVIEW LETTERS 2005; 94:057405. [PMID: 15783696 DOI: 10.1103/physrevlett.94.057405] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Indexed: 05/24/2023]
Abstract
The dynamics of water, confined on a nanometer length scale (1.7 to 4.0 nm) in sodium bis-(2-ethylhexyl) sulfosuccinate reverse micelles, is directly investigated using frequency resolved infrared vibrational echo experiments. The data are compared to bulk water and salt solution data. The experimentally determined frequency-frequency correlation functions show that the confined water dynamics is substantially slower than bulk water dynamics and is size dependent. The fastest dynamics (approximately 50 fs) is more similar to bulk water, while the slowest time scale dynamics is much slower than water, and, in analogy to bulk water, reflects the making and breaking of hydrogen bonds.
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Affiliation(s)
- Howe-Siang Tan
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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Yui H, Guo Y, Koyama K, Sawada T, John G, Yang B, Masuda M, Shimizu T. Local environment and property of water inside the hollow cylinder of a lipid nanotube. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:721-727. [PMID: 15641846 DOI: 10.1021/la040109a] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We investigated the local environment of water confined inside the hollow cylinder of lipid nanotubes (LNTs) by time-resolved fluorescent measurements and attenuated-total-reflectance infrared (ATR-IR) spectroscopy. The LNT was obtained by self-assembly of cardanyl glucosides in water at room temperature and had an open-ended cylindrical nanospace with a diameter of 10-15 nm, a length of 10-100 microm, and hydrophilic inner and outer surfaces. We introduced a fluorescent probe of 8-anilinonaphthalene-1-sulfonate into the confined water and observed an extremely slow dynamic Stokes shift with a correlation time of 1.26 ns, which was 2-3 orders of magnitude longer than that of bulk-phase water. From the peak shift of the fluorescent spectrum, the local solvent polarity (ET(30)) of the confined water was estimated as 50 kcal/mol, which is 20% lower than that in bulk water. ATR-IR measurements showed that the hydrogen-bond network of water inside the LNT was more developed than that in bulk water at room temperature, which is in contrast to the water in other self-assembled confined geometries, such as Aerosol-OT (AOT) reversed micelles.
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Affiliation(s)
- Hiroharu Yui
- CREST, Japan Science and Technology Agency, Nanoarchitectonics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
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Abel S, Sterpone F, Bandyopadhyay S, Marchi M. Molecular Modeling and Simulations of AOT−Water Reverse Micelles in Isooctane: Structural and Dynamic Properties. J Phys Chem B 2004. [DOI: 10.1021/jp047138e] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stéphane Abel
- Commissariat à l'Énergie Atomique, DSV-DBJC-SBFM, URA 2096/CNRS, Centre d'Études, Saclay, 91191 Gif-sur-Yvette Cedex, France, Laboratoire d'Imagerie Parametrique, UMR 7623 CNRS, Universite Pierre et Marie Curie, 15, rue de l'Ecole de Medecine, 75006 Paris Cedex, France, and Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India
| | - Fabio Sterpone
- Commissariat à l'Énergie Atomique, DSV-DBJC-SBFM, URA 2096/CNRS, Centre d'Études, Saclay, 91191 Gif-sur-Yvette Cedex, France, Laboratoire d'Imagerie Parametrique, UMR 7623 CNRS, Universite Pierre et Marie Curie, 15, rue de l'Ecole de Medecine, 75006 Paris Cedex, France, and Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India
| | - Sanjoy Bandyopadhyay
- Commissariat à l'Énergie Atomique, DSV-DBJC-SBFM, URA 2096/CNRS, Centre d'Études, Saclay, 91191 Gif-sur-Yvette Cedex, France, Laboratoire d'Imagerie Parametrique, UMR 7623 CNRS, Universite Pierre et Marie Curie, 15, rue de l'Ecole de Medecine, 75006 Paris Cedex, France, and Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India
| | - Massimo Marchi
- Commissariat à l'Énergie Atomique, DSV-DBJC-SBFM, URA 2096/CNRS, Centre d'Études, Saclay, 91191 Gif-sur-Yvette Cedex, France, Laboratoire d'Imagerie Parametrique, UMR 7623 CNRS, Universite Pierre et Marie Curie, 15, rue de l'Ecole de Medecine, 75006 Paris Cedex, France, and Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India
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Hirose Y, Yui H, Sawada T. The Ultrafast Relaxation Dynamics of a Viscosity Probe Molecule in an AOT-Reversed Micelle: Contribution of the Specific Interactions with the Local Environment. J Phys Chem B 2004. [DOI: 10.1021/jp0370775] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yasushi Hirose
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan, and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Hiroharu Yui
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan, and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Tsuguo Sawada
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan, and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
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Hunt NT, Jaye AA, Hellman A, Meech SR. Ultrafast Dynamics of Styrene Microemulsions, Polystyrene Nanolatexes, and Structural Analogues of Polystyrene. J Phys Chem B 2003. [DOI: 10.1021/jp035624g] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Neil T. Hunt
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Andrew A. Jaye
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Alexander Hellman
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Stephen R. Meech
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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Hunt NT, Jaye AA, Meech SR. Ultrafast Dynamics in Microemulsions: Optical Kerr Effect Study of the Dispersed Oil Phase in a Carbon Disulfide−Dodecyltrimethylammonium Bromide−Water Microemulsion. J Phys Chem B 2003. [DOI: 10.1021/jp022301w] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Neil T. Hunt
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Andrew A. Jaye
- 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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Affiliation(s)
- Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
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Boyd JE, Briskman A, Sayes CM, Mittleman D, Colvin V. Terahertz Vibrational Modes of Inverse Micelles. J Phys Chem B 2002. [DOI: 10.1021/jp0255740] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joel E. Boyd
- Department of Chemistry, and Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
| | - Ari Briskman
- Department of Chemistry, and Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
| | - Christie M. Sayes
- Department of Chemistry, and Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
| | - Daniel Mittleman
- Department of Chemistry, and Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
| | - Vicki Colvin
- Department of Chemistry, and Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
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