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Water clusters in liquid organic matrices of different polarity. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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Matthews L, Ruscigno S, Rogers SE, Bartlett P, Johnson AJ, Sochon R, Briscoe WH. Fracto-eutectogels: SDS fractal dendrites via counterion condensation in a deep eutectic solvent. Phys Chem Chem Phys 2021; 23:11672-11683. [PMID: 33978002 DOI: 10.1039/d1cp01370j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Glyceline, a deep eutectic solvent comprising glycerol and choline chloride, is a green nonaqueous solvent with potential industrial applications. Molecular mechanisms of surfactant self-assembly in deep eutectic solvents are expected to differ from those in their constituent polar components and are not well understood. Here we report the observation of self-assembled SDS fractal dendrites with dimensions up to ∼mm in glyceline at SDS concentrations as low as cSDS ∼ 0.1 wt%. The prevalence of these dendritic fractal aggregates led to the formation of a gel phase at SDS concentrations above ≥1.9 wt% (the critical gelation concentration cCGC). The gel microscopic structure was visualised using polarised light microscopy (PLM); rheology measurements confirmed the formation of a colloidal gel, where the first normal stress difference was negative and the elastic modulus was dominant. Detailed nano-structural characterisation by small-angle neutron scattering (SANS) further confirmed the presence of fractal aggregates. Such SDS aggregation or gelation has not been observed in water at such low surfactant concentrations, whereas SDS has been reported to form lamellar aggregates in glycerol (a component of glyceline). We attribute the formation of the SDS fractal dendrites to the condensation of counterions (i.e. the choline ions) around the SDS aggregates - a diffusion-controlled process, leading to the aggregate morphology observed. These unprecedented results shed light on the molecular mechanisms of surfactant self-assembly in deep eutectic solvents, important to their application in industrial formulation.
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Affiliation(s)
- Lauren Matthews
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK. and Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - Silvia Ruscigno
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - Sarah E Rogers
- ISIS Muon and Neutron Source, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0QX, UK
| | - Paul Bartlett
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | | | - Robert Sochon
- GlaxoSmithKline, St George's Avenue, Weybridge, KT13 0DE, UK
| | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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3
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Jamali SH, Bardow A, Vlugt TJH, Moultos OA. Generalized Form for Finite-Size Corrections in Mutual Diffusion Coefficients of Multicomponent Mixtures Obtained from Equilibrium Molecular Dynamics Simulation. J Chem Theory Comput 2020; 16:3799-3806. [PMID: 32338889 PMCID: PMC7288667 DOI: 10.1021/acs.jctc.0c00268] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
![]()
The system-size dependence
of computed mutual diffusion coefficients
of multicomponent mixtures is investigated, and a generalized correction
term is derived. The generalized finite-size correction term was validated
for the ternary molecular mixture chloroform/acetone/methanol as well
as 28 ternary LJ systems. It is shown that only the diagonal elements of the Fick matrix
show system-size dependency. The finite-size effects of these elements
can be corrected by adding the term derived by Yeh and Hummer (J. Phys. Chem. B2004, 108, 15873–15879). By performing an eigenvalue analysis of the
finite-size effects of the matrix of Fick diffusivities we show that
the eigenvector matrix of Fick diffusivities does not depend on the
size of the simulation box. Only eigenvalues, which describe the speed
of diffusion, depend on the size of the system. An analytic relation
for finite-size effects of the matrix of Maxwell–Stefan diffusivities
was developed. All Maxwell–Stefan diffusivities depend on the
system size, and the required correction depends on the matrix of
thermodynamic factors.
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Affiliation(s)
- Seyed Hossein Jamali
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - André Bardow
- Institute of Technical Thermodynamics, RWTH Aachen University, 52056 Aachen, Germany.,Energy Process Systems Engineering, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, 8092 Zürich, Switzerland
| | - Thijs J H Vlugt
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - Othonas A Moultos
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
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4
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Jamali SH, Wolff L, Becker TM, Bardow A, Vlugt TJH, Moultos OA. Finite-Size Effects of Binary Mutual Diffusion Coefficients from Molecular Dynamics. J Chem Theory Comput 2018; 14:2667-2677. [PMID: 29664633 PMCID: PMC5943679 DOI: 10.1021/acs.jctc.8b00170] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dynamics simulations were performed for the prediction of the finite-size effects of Maxwell-Stefan diffusion coefficients of molecular mixtures and a wide variety of binary Lennard-Jones systems. A strong dependency of computed diffusivities on the system size was observed. Computed diffusivities were found to increase with the number of molecules. We propose a correction for the extrapolation of Maxwell-Stefan diffusion coefficients to the thermodynamic limit, based on the study by Yeh and Hummer ( J. Phys. Chem. B , 2004 , 108 , 15873 - 15879 ). The proposed correction is a function of the viscosity of the system, the size of the simulation box, and the thermodynamic factor, which is a measure for the nonideality of the mixture. Verification is carried out for more than 200 distinct binary Lennard-Jones systems, as well as 9 binary systems of methanol, water, ethanol, acetone, methylamine, and carbon tetrachloride. Significant deviations between finite-size Maxwell-Stefan diffusivities and the corresponding diffusivities at the thermodynamic limit were found for mixtures close to demixing. In these cases, the finite-size correction can be even larger than the simulated (finite-size) Maxwell-Stefan diffusivity. Our results show that considering these finite-size effects is crucial and that the suggested correction allows for reliable computations.
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Affiliation(s)
- Seyed Hossein Jamali
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering , Delft University of Technology , Leeghwaterstraat 39 , 2628CB Delft , The Netherlands
| | - Ludger Wolff
- Institute of Technical Thermodynamics , RWTH Aachen University , 52056 Aachen , Germany
| | - Tim M Becker
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering , Delft University of Technology , Leeghwaterstraat 39 , 2628CB Delft , The Netherlands
| | - André Bardow
- Institute of Technical Thermodynamics , RWTH Aachen University , 52056 Aachen , Germany
| | - Thijs J H Vlugt
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering , Delft University of Technology , Leeghwaterstraat 39 , 2628CB Delft , The Netherlands
| | - Othonas A Moultos
- Engineering Thermodynamics, Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering , Delft University of Technology , Leeghwaterstraat 39 , 2628CB Delft , The Netherlands
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6
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Cao Z, Voth GA. The multiscale coarse-graining method. XI. Accurate interactions based on the centers of charge of coarse-grained sites. J Chem Phys 2016; 143:243116. [PMID: 26723601 DOI: 10.1063/1.4933249] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It is essential to be able to systematically construct coarse-grained (CG) models that can efficiently and accurately reproduce key properties of higher-resolution models such as all-atom. To fulfill this goal, a mapping operator is needed to transform the higher-resolution configuration to a CG configuration. Certain mapping operators, however, may lose information related to the underlying electrostatic properties. In this paper, a new mapping operator based on the centers of charge of CG sites is proposed to address this issue. Four example systems are chosen to demonstrate this concept. Within the multiscale coarse-graining framework, CG models that use this mapping operator are found to better reproduce the structural correlations of atomistic models. The present work also demonstrates the flexibility of the mapping operator and the robustness of the force matching method. For instance, important functional groups can be isolated and emphasized in the CG model.
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Affiliation(s)
- Zhen Cao
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, and Computation Institute, The University of Chicago, 5735 S Ellis Ave., Chicago, Illinois 60637, USA
| | - Gregory A Voth
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, and Computation Institute, The University of Chicago, 5735 S Ellis Ave., Chicago, Illinois 60637, USA
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7
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Guevara-Carrion G, Janzen T, Muñoz-Muñoz YM, Vrabec J. Mutual diffusion of binary liquid mixtures containing methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride. J Chem Phys 2016; 144:124501. [DOI: 10.1063/1.4943395] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
| | - Tatjana Janzen
- Thermodynamics and Energy Technology, University of Paderborn, 33098 Paderborn, Germany
| | | | - Jadran Vrabec
- Thermodynamics and Energy Technology, University of Paderborn, 33098 Paderborn, Germany
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Tummala NR, Liu S, Argyris D, Striolo A. Interfacial water properties in the presence of surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2084-2094. [PMID: 25631335 DOI: 10.1021/la504388r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Water, because of its fundamental role in biology, geology, and many industrial applications and its anomalous behavior compared to that of simple fluids, continues to fascinate and attract extensive scientific interest. Building on previous studies of water in contact with different surfaces, in this study, we report results obtained from molecular dynamics simulations of water near hydrophilic and hydrophobic interfaces in the presence of nonionic and ionic amphiphilic molecules, hexaethylene glycol monododecyl ether (C12E6) and sodium dodecyl sulfate (SDS). We elucidate how these surfactants affect the packing (i.e., density profiles) and orientation of interfacial water. The results highlight the interplay of both surfactant charges and the substrate charge distribution predominantly with respect to the orientation of water molecules, up to distances longer than those expected based on simulation results on flat solid surfaces. We also quantify the dynamics of interfacial water molecules by computing the residence probability for water in contact with various substrates. We compare our results to those previously obtained for interfacial water on silica and graphite and also with experimental sum-frequency vibrational spectroscopy results at the air-water interface in the presence of surfactants. Our analysis could be useful for a better understanding of interfacial water not only near solid substrates but also near self-assembled/aggregated molecules at a variety of interfaces.
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Affiliation(s)
- Naga Rajesh Tummala
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive, Atlanta, Georgia 30318, United States
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9
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Frasch DM, Spiegel DR. Experiments on tracer diffusion in aqueous and non-aqueous solvent combinations. J Chem Phys 2014; 141:124507. [PMID: 25273451 DOI: 10.1063/1.4896303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Forced Rayleigh scattering is used to study the tracer diffusion of an azobenzene in binary combinations of polar solvents, including water. In the absence of water, the tracer diffusion coefficient D in the mixture lies between the diffusion coefficients within the pure solvents, on a curve that is reasonably close to the prediction of free-volume theory. If water is present, on the other hand, the diffusion coefficient displays a minimum that is less than the smaller of the two pure-solvent values. We attempt to understand the different behavior in water by concentrating on the fairly hydrophobic nature of the solute, leading to a first solvent shell that is hydrophobic on the inside and hydrophilic on the outside. We also believe that clusters of amphiphiles explain the observation that, in aqueous combinations, D is nearly constant above a certain amphiphile mole fraction.
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Affiliation(s)
- Duncan M Frasch
- Department of Physics and Astronomy, Trinity University, San Antonio, Texas 78212, USA
| | - Daniel R Spiegel
- Department of Physics and Astronomy, Trinity University, San Antonio, Texas 78212, USA
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10
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Calero C, Gordillo MC, Martí J. Size effects on water adsorbed on hydrophobic probes at the nanometric scale. J Chem Phys 2014; 138:214702. [PMID: 23758390 DOI: 10.1063/1.4807092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Molecular dynamics simulations of liquid water at ambient conditions, adsorbed at the external walls of (n,n) single-walled armchair carbon nanotubes have been performed for n = 5, 9, 12. The comparison with the case of water adsorbed on graphene has also been included. The analysis of Helmholtz free energies reveals qualitatively different ranges of thermodynamical stability, eventually starting at a given threshold surface density. We observed that, in the framework of the force field considered here, water does not wet graphene nor (12,12) tubes, but it can coat thinner tubes such as (9,9) and (5,5), which indicates that the width of the carbon nanotube plays a role on wetting. On the other hand, density profiles, orientational distributions of water, and hydrogen-bond populations indicate significant changes of structure of water for the different surfaces. Further, we computed self-diffusion of water and spectral densities of water and carbon molecules, which again revealed different qualitative behavior of interfacial water depending on the size of the nanotube. The crossover size corresponds to tube diameters of around 1 nm.
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Affiliation(s)
- C Calero
- Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain
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11
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Chen YC, Tang PH, Wu TM. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view. J Chem Phys 2013; 139:204505. [PMID: 24289362 DOI: 10.1063/1.4829679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.
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Affiliation(s)
- Yu-Chun Chen
- Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan
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12
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Chang M, Choi D, Fu B, Reichmanis E. Solvent based hydrogen bonding: impact on poly(3-hexylthiophene) nanoscale morphology and charge transport characteristics. ACS NANO 2013; 7:5402-5413. [PMID: 23651389 DOI: 10.1021/nn401323f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate that supramolecular assembly and subsequent enhancement of charge transport characteristics of conjugated polymers can be facilitated simply by adding small amounts of a more volatile poor solvent, which can hydrogen bond with the majority solvent. Addition of up to 2 vol % acetone to a precursor solution of poly(3-hexylthiophene) (P3HT) in chloroform leads to approximately a 4-fold increase in P3HT field-effect mobility. The improvement is associated with hydrogen bonding interactions between acetone and chloroform which decrease the evaporation rate of the mixed solvent. P3HT is less soluble in the binary solvent than in the more readily vaporized chloroform component, and this characteristic enables the supramolecular assembly of P3HT chains at the nanoscale. Two-dimensional molecular ordering of the polymer film was controlled by varying the quantity of poor solvent added to the precursor solution, and the correlation between field-effect mobility and molecular ordering was investigated. Hansen solubility parameters were used to systematically understand how the solvent mixture enhances the alignment and assembly of polymer chains and influences subsequent thin film properties. The value of the relative energy difference (RED) of the solvent with respect to P3HT increased from less than 1 to more than 1 during film formation, which indicates that the solvent characteristics are initially those of a good solvent but transform into those of a poor dissolution medium. A mechanistic illustration of the molecular ordering process during film formation is postulated.
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Affiliation(s)
- Mincheol Chang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100, USA
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13
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Dreger ZA, McCluskey MD, Gupta YM. High pressure-high temperature decomposition of γ-cyclotrimethylene trinitramine. J Phys Chem A 2012; 116:9680-8. [PMID: 22971173 DOI: 10.1021/jp307373v] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Decomposition of γ-cyclotrimethylene trinitramine (γ-RDX) under high pressure-high temperature conditions was examined to elucidate the reactive behavior of RDX crystals. Vibrational spectroscopy measurements were obtained for single crystals in a diamond anvil cell (DAC) at pressures from 6 to 12 GPa and temperatures up to 600 K. Global decomposition rates, activation energies, and activation volumes at several pressures and temperatures below the P-T locus for the γ-RDX decomposition were obtained. Similar to ε-RDX, but in contrast to α-RDX, we found that pressure decelerates the decomposition of γ-RDX. The decomposition deceleration with pressure in the γ-phase can be attributed to pressure-inhibiting bond homolysis step(s). The main decomposition species were identified as N(2)O, CO(2), and H(2)O, in accord with the species reported for the α-phase decomposition at high pressures. This work complements previous studies on RDX at HP-HT conditions and provides comprehensive results on the reactive behavior of γ-RDX; the γ-phase plays a key role in RDX decomposition at P-T conditions relevant to shock wave initiation.
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Affiliation(s)
- Zbigniew A Dreger
- Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816, USA.
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14
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Liu X, Martín-Calvo A, McGarrity E, Schnell SK, Calero S, Simon JM, Bedeaux D, Kjelstrup S, Bardow A, Vlugt TJH. Fick Diffusion Coefficients in Ternary Liquid Systems from Equilibrium Molecular Dynamics Simulations. Ind Eng Chem Res 2012. [DOI: 10.1021/ie301009v] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Xin Liu
- Lehrstuhl für Technische Thermodynamik, RWTH Aachen University, Schinkelstraße 8, 52062
Aachen, Germany
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Ana Martín-Calvo
- Physical, Chemical, and Natural Systems, University Pablo de Olavide Ctra. de Utrera, km. 1
Sevilla, Spain
| | - Erin McGarrity
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Sondre K. Schnell
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Sofía Calero
- Physical, Chemical, and Natural Systems, University Pablo de Olavide Ctra. de Utrera, km. 1
Sevilla, Spain
| | - Jean-Marc Simon
- Laboratoire
Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS-Universite de Bourgogne, Dijon, France
| | - Dick Bedeaux
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway
| | - Signe Kjelstrup
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway
| | - André Bardow
- Lehrstuhl für Technische Thermodynamik, RWTH Aachen University, Schinkelstraße 8, 52062
Aachen, Germany
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Thijs J. H. Vlugt
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
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Liu X, Schnell SK, Simon JM, Bedeaux D, Kjelstrup S, Bardow A, Vlugt TJH. Fick Diffusion Coefficients of Liquid Mixtures Directly Obtained From Equilibrium Molecular Dynamics. J Phys Chem B 2011; 115:12921-9. [DOI: 10.1021/jp208360s] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xin Liu
- Lehrstuhl für Technische Thermodynamik, RWTH Aachen University, Schinkelstrasse 8, 52062 Aachen, Germany
- Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Sondre K. Schnell
- Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Jean-Marc Simon
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS-Universite de Bourgogne, Dijon, France
| | - Dick Bedeaux
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway
| | - Signe Kjelstrup
- Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway
| | - André Bardow
- Lehrstuhl für Technische Thermodynamik, RWTH Aachen University, Schinkelstrasse 8, 52062 Aachen, Germany
- Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
| | - Thijs J. H. Vlugt
- Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
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16
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Affiliation(s)
- Alberto Striolo
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, U.S.A
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17
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Martí J, Sala J, Guàrdia E. Molecular dynamics simulations of water confined in graphene nanochannels: From ambient to supercritical environments. J Mol Liq 2010. [DOI: 10.1016/j.molliq.2009.09.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Rimaz M, Noroozi Pesyan N, Khalafy J. Tautomerism and isotopic multiplets in the 13C NMR spectra of partially deuterated 3-arylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones and their sulfur analogs--evidence for elucidation of the structure backbone and tautomeric forms. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48:276-285. [PMID: 20169579 DOI: 10.1002/mrc.2573] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The tautomerism of the synthesized 3-arylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones (1a-d) and 3-aryl-7-thioxo-7,8-dihydro-6H-pyrimido[4,5-c]pyridazine-5-ones (2a-d) was studied in dimethyl sulfoxide (DMSO)-d(6). (1)H NMR spectra of 1a-d showed a clustered water molecule in the structure backbone that is attached by strong intermolecular H bonding. The relation between the temperature and H bonding of the clustered water molecule with 1a was also studied as representative. The relation between the electronegativity (chi) of the substituent on phenyl ring and the chemical shifts of clustered water protons in 1a-d was also studied. All of 1a-d and also 2d compounds existed in lactam (I) form, whereas 2a-c compounds have two distinguished tautomers in DMSO-d(6) [lactam (I) and lactim (II) forms]. The solvent-substrate proton exchange was examined in compounds 1a-d and 2a-d by adding one drop of D(2)O. All compounds (except 1d) showed proton/deuterium exchange of the clustered water protons in DMSO by adding one drop of D(2)O. Some compounds (but not all of them) that are easily soluble in DMSO-d(6) containing D(2)O showed isotopic splitting (beta-isotope effect) in their (13)C NMR spectra. Among them, compound 1a was the best evidence to help the spectral assignments and structure determination of predominant tautomer by carbon-13 splitting (beta-isotope effect).
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Affiliation(s)
- Mehdi Rimaz
- Department of Chemistry, Faculty of Science, Urmia University, 57159 Urmia, Iran
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19
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Gordillo MC, Martí J. Effect of Surface Roughness on the Static and Dynamic Properties of Water Adsorbed on Graphene. J Phys Chem B 2010; 114:4583-9. [DOI: 10.1021/jp9114332] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. C. Gordillo
- Departamento de Sistemas Físicos, Químicos y Naturales, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, Carretera de Utrera, km 1, 41013 Sevilla, Spain
| | - J. Martí
- Departament de Física i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4−B5 Campus Nord, 08034 Barcelona, Catalonia, Spain
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Malsam J, Aksan A. Hydrogen Bonding and Compartmentalization of Water in Supercooled and Frozen Aqueous Acetone Solutions. J Phys Chem B 2010; 114:4238-45. [DOI: 10.1021/jp904381d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jason Malsam
- Biostabilization Laboratory, Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN
| | - Alptekin Aksan
- Biostabilization Laboratory, Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN
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21
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Tummala NR, Striolo A. Curvature effects on the adsorption of aqueous sodium-dodecyl-sulfate surfactants on carbonaceous substrates: structural features and counterion dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:021408. [PMID: 19792125 DOI: 10.1103/physreve.80.021408] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Indexed: 05/28/2023]
Abstract
The effect of substrate curvature on surfactant self-assembly has been studied using all-atom molecular-dynamics simulations. We studied aqueous sodium-dodecyl-sulfate (SDS) surfactants on graphite, on the outer surface of single walled carbon nanotubes (SWNTs) and within SWNTs. Our results reveal that although the chemical nature of the substrates is constant, the self-assembled structures change significantly as the curvature varies. For example, at large surface density, SDS surfactants yield micellar structures on graphite, layered self-assemblies outside SWNTs, and cylindrical lamellar structures inside SWNTs. Changes in substrate curvature as well as surfactant surface density affect significantly surfactant orientation and, more importantly, headgroup-headgroup distribution, headgroup-counterion packing, and counterion residence time next to the headgroups.
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Affiliation(s)
- Naga Rajesh Tummala
- School of Chemical, Biological, and Materials Engineering, The University of Oklahoma, Norman, Oklahoma 73019, USA
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22
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Martí J, Sala J, Guàrdia E, Gordillo MC. Molecular dynamics simulations of supercritical water confined within a carbon-slit pore. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:031606. [PMID: 19391953 DOI: 10.1103/physreve.79.031606] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Indexed: 05/12/2023]
Abstract
We report the results of a series of molecular dynamics simulations of water inside a carbon-slit pore at supercritical conditions. A range of densities corresponding from liquid (0.66gcm;{-3}) to gas environments (0.08gcm;{-3}) at the supercritical temperature of 673K were considered. Our findings are compared with previous studies of liquid water confined in graphene nanochannels at ambient and high temperatures, and indicate that the microscopic structure of water evolves from hydrogen bond networks characteristic of hot dense liquids to looser arrangements where the dominant units are water monomers and dimers. Water permittivity was found to be very small at low densities, with a tendency to grow with density and to reach typical values of unconfined supercritical water at 0.66gcm;{-3}) . In supercritical conditions, the residence time of water at interfaces is roughly similar to that of water in the central regions of the slabs, if the size of the considered region is taken into account. That time span is long enough to compute dynamical properties such as diffusion or spectral densities. Water diffusion in supercritical states is much faster at low densities, and it is produced in such a way that, at interfaces, translational diffusion is mainly produced along planes parallel to the carbon walls. Spectral frequency shifts depend on several factors, being temperature and density effects the most relevant. However, we can observe corrections due to confinement, important both at the graphene interface and in the central region of the water slab.
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Affiliation(s)
- J Martí
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, B4-B5 Campus Nord, 08034 Barcelona, Catalonia, Spain.
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