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Naito H, Sumi T, Koga K. How do water-mediated interactions and osmotic second virial coefficients vary with particle size? Faraday Discuss 2024; 249:440-452. [PMID: 37791511 DOI: 10.1039/d3fd00104k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We examine quantitatively the solute-size dependences of the effective interactions between nonpolar solutes in water and in a simple liquid. The potential w(r) of mean force and the osmotic second virial coefficients B are calculated with high accuracy from molecular dynamics simulations. As the solute diameter increases from methane's to C60's with the solute-solute and solute-solvent attractive interaction parameters fixed to those for the methane-methane and methane-water interactions, the first minimum of w(r) lowers from -1.1 to -4.7 in units of the thermal energy kT. Correspondingly, the magnitude of B (<0) increases proportional to σα with some power close to 6 or 7, which reinforces the solute-size dependence of B found earlier for a smaller range of σ [H. Naito, R. Okamoto, T. Sumi and K. Koga, J. Chem. Phys., 2022, 156, 221104]. We also demonstrate that the strength of the attractive interactions between solute and solvent molecules can qualitatively change the characteristics of the effective pair interaction between solute particles, both in water and in a simple liquid. If the solute-solvent attractive force is set to be weaker (stronger) than a threshold, the effective interaction becomes increasingly attractive (repulsive) with increasing solute size.
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Affiliation(s)
- Hidefumi Naito
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Tomonari Sumi
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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Taira A, Okamoto R, Sumi T, Koga K. Solvation free energies of alcohols in water: temperature and pressure dependences. Phys Chem Chem Phys 2023; 25:31107-31117. [PMID: 37947179 DOI: 10.1039/d3cp03799a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Solvation free energies μ* of amphiphilic species, methanol and 1,2-hexanediol, are obtained as a function of temperature or pressure based on molecular dynamics simulations combined with efficient free-energy calculation methods. In general, μ* of an amphiphile can be divided into and , the nonpolar and electrostatic contributions, and the former is further divided into and which are the work of cavity formation process and the free energy change due to weak, attractive interactions between the solute molecule and surrounding solvent molecules. We demonstrate that μ* of the two amphiphilic solutes can be obtained accurately using a perturbation combining method, which relies on the exact expressions for and and requires no simulations of intermediate systems between the solute with strong, repulsive interactions and the solute with the van der Waals and electrostatic interactions. The decomposition of μ* gives us several physical insights including that μ* is an increasing function of T due to , that the contributions of hydrophilic groups to the temperature dependence of μ* are additive, and that the contribution of the van der Waals attraction to the solvation volume is greater than that of the electrostatic interactions.
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Affiliation(s)
- Aoi Taira
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Ryuichi Okamoto
- Graduate School of Information Science, University of Hyogo, Kobe, Hyogo, 650-0047, Japan
| | - Tomonari Sumi
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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Naito H, Okamoto R, Sumi T, Koga K. Osmotic second virial coefficients for hydrophobic interactions as a function of solute size. J Chem Phys 2022; 156:221104. [PMID: 35705398 DOI: 10.1063/5.0097547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To gain quantitative insight into how the overall strength of the hydrophobic interaction varies with the molecular size, we calculate osmotic second virial coefficients B for hydrophobic spherical molecules of different diameters σ in water based on molecular simulation with corrections to the finite-size and finite-concentration effects. It is shown that B (<0) changes by two orders of magnitude greater as σ increases twofold and its solute-size dependence is best fit by a power law B ∝ σα with the exponent α ≃ 6, which contrasts with the cubic power law that the second virial coefficients of gases obey. It is also found that values of B for the solutes in a nonpolar solvent are positive but they obey the same power law as in water. A thermodynamic identity for B derived earlier [K. Koga, V. Holten, and B. Widom, J. Phys. Chem. B 119, 13391 (2015)] indicates that if B is asymptotically proportional to a power of σ, the exponent α must be equal to or greater than 6.
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Affiliation(s)
- Hidefumi Naito
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Ryuichi Okamoto
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Tomonari Sumi
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan
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Okamoto R, Koga K. Theory of Gas Solubility and Hydrophobic Interaction in Aqueous Electrolyte Solutions. J Phys Chem B 2021; 125:12820-12831. [PMID: 34756051 DOI: 10.1021/acs.jpcb.1c08050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ion-specific effects on the solubility of nonpolar solutes and on the solute-solute hydrophobic interaction in aqueous electrolyte solutions are studied on the basis of a continuum theory that incorporates the excluded volume of the molecules using the four-component (water, cations, anions, and solutes) Boublı́k-Mansoori-Carnahan-Starling-Leland model and ion hydration (electrostriction) using the Born model. We examine how the ordering of ions in the salt effect on the solubility as measured by the Sechenov coefficient KS changes with varying sizes of ions and solutes. Our calculation reproduces the general trend of experimentally measured KS and also provides insight into the irregular behavior of KS for lithium ion. The correlation between KS and the salt effect on the hydrophobic interaction that has been pointed out earlier is accounted for by an explicit connection between KS and the salt-enhanced-association coefficient CI in the expansion of the second osmotic virial coefficient B(ns) = B(0) - CIns + ··· in powers of the salt density ns at fixed pressure and temperature. The quadratic relation CI≈KS2/4 is derived for ions and solutes that are not very large.
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Affiliation(s)
- Ryuichi Okamoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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Okamoto R, Koga K, Onuki A. Theory of electrolytes including steric, attractive, and hydration interactions. J Chem Phys 2020; 153:074503. [PMID: 32828079 DOI: 10.1063/5.0015446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We present a continuum theory of electrolytes composed of a waterlike solvent and univalent ions. First, we start with a density functional F for the coarse-grained solvent, cation, and anion densities, including the Debye-Hückel free energy, the Coulombic interaction, and the direct interactions among these three components. These densities fluctuate obeying the distribution ∝exp(-F/kBT). Eliminating the solvent density deviation in F, we obtain the effective non-Coulombic interactions among the ions, which consist of the direct ones and the solvent-mediated ones. We then derive general expressions for the ion correlation, the apparent partial volume, and the activity and osmotic coefficients up to linear order in the average salt density ns. Second, we perform numerical analysis using the Mansoori-Carnahan-Starling-Leland model [J. Chem. Phys. 54, 1523 (1971)] for three-component hardspheres. The effective interactions sensitively depend on the cation and anion sizes due to competition between the steric and hydration effects, which are repulsive between small-large ion pairs and attractive between symmetric pairs. These agree with previous experiments and Collins' rule [Biophys. J. 72, 65 (1997)]. We also give simple approximate expressions for the ionic interaction coefficients valid for any ion sizes.
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Affiliation(s)
- Ryuichi Okamoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kenichiro Koga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Akira Onuki
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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Chialvo AA, Crisalle OD. On the behavior of the osmotic second virial coefficients of gases in aqueous solutions: Rigorous results, accurate approximations, and experimental evidence. J Chem Phys 2019; 150:124503. [DOI: 10.1063/1.5047525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
| | - Oscar D. Crisalle
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
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Lidon P, Marker SC, Wilson JJ, Williams RM, Zipfel WR, Stroock AD. Enhanced Oxygen Solubility in Metastable Water under Tension. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12017-12024. [PMID: 30221943 DOI: 10.1021/acs.langmuir.8b02408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite its relevance in numerous natural and industrial processes, the solubility of molecular oxygen has never been directly measured in capillary-condensed liquid water. In this article, we measure oxygen solubility in liquid water trapped within nanoporous samples, in metastable equilibrium with a subsaturated vapor. We show that solubility increases two fold at moderate subsaturations (relative humidity ∼0.55). This evolution with relative humidity is in good agreement with a simple thermodynamic prediction using properties of bulk water, previously verified experimentally at positive pressure. Our measurement thus verifies the validity of this macroscopic thermodynamic theory to strong confinement and large negative pressures, where significant nonidealities are expected. This effect has strong implications for important oxygen-dependent chemistries in natural and technological contexts.
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Affiliation(s)
- Pierre Lidon
- Robert Frederick Smith School of Chemical and Biomolecular Engineering , Cornell University , 120 Olin Hall , Ithaca , New York 14853 , United States
- CNRS, Solvay, LOF, UMR 5258, Univ. Bordeaux , 178 avenue du Dr. Schweitzer Pessac F-33600 , France
| | - Sierra C Marker
- Department of Chemistry and Chemical Biology , Cornell University , Baker Lab , Ithaca , New York 14853 , United States
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology , Cornell University , Baker Lab , Ithaca , New York 14853 , United States
| | - Rebecca M Williams
- Department Biomedical Engineering , Cornell University , Weill Hall , Ithaca , New York 14853 , United States
| | - Warren R Zipfel
- Department Biomedical Engineering , Cornell University , Weill Hall , Ithaca , New York 14853 , United States
| | - Abraham D Stroock
- Robert Frederick Smith School of Chemical and Biomolecular Engineering , Cornell University , 120 Olin Hall , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell for Nanoscale Science , Physical Sciences Building , Ithaca , New York 14853 , United States
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Okamoto R, Onuki A. Theory of nonionic hydrophobic solutes in mixture solvent: Solvent-mediated interaction and solute-induced phase separation. J Chem Phys 2018; 149:014501. [DOI: 10.1063/1.5037673] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryuichi Okamoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Akira Onuki
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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Chialvo AA. Gas solubility in dilute solutions: A novel molecular thermodynamic perspective. J Chem Phys 2018; 148:174502. [DOI: 10.1063/1.5023893] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Koga K, Yamamoto N. Hydrophobicity Varying with Temperature, Pressure, and Salt Concentration. J Phys Chem B 2018; 122:3655-3665. [PMID: 29357255 DOI: 10.1021/acs.jpcb.7b12193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Temperature-, pressure-, and salt-concentration-induced variations in the solubility of small nonpolar solutes in aqueous solution and the corresponding variations in the solvent-induced pair attraction between such solute molecules are investigated. The variations in the solvation free energy of a solute and those in the solvent-induced pair attraction are well reproduced by a mean-field approximation in which the repulsive cores of solute molecules are treated as hard spheres and the mean-field energy of a solute molecule is taken to be the average potential energy that the solute molecule feels in solution. The mechanisms of variation in the solvation free energy and those of variation in the solvent-induced pair potential, with increasing temperature, pressure, and salt concentration, are clarified. Correlations between the solvation free energy and the solvent-induced pair potential at a contact distance in temperature, pressure, and salt concentration variations are near linear in any mode of variation, but the slope of the linear relation is dependent on the mode of variation and is determined by a ratio of the solvation thermodynamic quantities characteristic of each mode of variation.
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Affiliation(s)
- K Koga
- Research Institute for Interdisciplinary Science , Okayama University , Okayama 700-8530 , Japan.,Department of Chemistry, Faculty of Science , Okayama University , Okayama 700-8530 , Japan
| | - N Yamamoto
- Department of Chemistry, Faculty of Science , Okayama University , Okayama 700-8530 , Japan
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Cerdeiriña CA, Debenedetti PG. Water’s Thermal Pressure Drives the Temperature Dependence of Hydrophobic Hydration. J Phys Chem B 2017; 122:3620-3625. [DOI: 10.1021/acs.jpcb.7b11100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claudio A. Cerdeiriña
- Departamento de Física Aplicada, Universidad de Vigo—Campus del Agua, Ourense 32004, Spain
| | - Pablo G. Debenedetti
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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