Prediction of the concentration dependence of the surface tension and density of salt solutions: atomistic simulations using Drude oscillator polarizable and nonpolarizable models

Neyt, Jean-Claude; Wender, Aurélie; Lachet, Véronique; Ghoufi, Aziz; Malfreyt, Patrice

doi:10.1039/c3cp50904d

Cited by 32 publications

(54 citation statements)

References 91 publications

(156 reference statements)

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“…24,[26][27][28]32 This is exemplarily shown in Fig. The attraction between acetone molecules is much more pronounced, not only due to its high Lennard-Jones energy parameters, but also due to its strong dipole moment m = 3.4 D. Therefore, the adsorption of the volatile component at the interface is more distinct in this case.…”

Section: Density Profiles Across the Vle Interfacementioning

confidence: 73%

Fluid phase interface properties of acetone, oxygen, nitrogen and their binary mixtures by molecular simulation

Eckelsbach

Vrabec

2015

Phys. Chem. Chem. Phys.

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Vapor-liquid equilibria (VLE) of the pure substances acetone, oxygen and nitrogen as well as their binary mixtures are studied by molecular dynamics (MD) simulation with a direct approach. Thereby, particular attention is paid to the interface behavior on the molecular level, yielding total and partial density profiles as well as surface tension data. The classical approach by van der Waals is used to analyze the total density profiles. It is found that an extended function is needed to describe those profiles for the mixtures containing acetone, due to the strong adsorption of the volatile component at the vapor side of the interface. Based on these representations the interface thickness is studied. The surface tension results are compared to experimental data, correlations thereof and results from other molecular approaches. Due to the scarcity of experiments, the parachor method is employed to obtain predictive surface tension data for the mixtures. Following the same approach, the present surface tension results are correlated for the mixtures containing acetone.

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Section: Density Profiles Across the Vle Interfacementioning

confidence: 73%

Fluid phase interface properties of acetone, oxygen, nitrogen and their binary mixtures by molecular simulation

Eckelsbach

Vrabec

2015

Phys. Chem. Chem. Phys.

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“…The surface tension for pure water varies by over 30 dyn/cm for different water models [46,61,62], so surface tension is very sensitive to the details of the intermolecular interactions. Simulations using non-polarizable models have found good agreement for the surface tension for aqueous NaCl [63][64][65], while the results using polarizable models are not as good, showing a decrease in the surface tension [65]. We are encouraged that the DCT models give the correct trend.…”

Section: Resultsmentioning

confidence: 96%

Ion clustering in aqueous salt solutions near the liquid/vapor interface

Smith¹,

Rick²

2016

Condens. Matter Phys.

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Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide salts, which have a greater surface affinity, have a larger roughness. This suggests that ions away from the surface and ions near the surface affect the interface in opposite ways.

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“…In spite of this long and venerable history, the interaction of ions with hydrophobic interfaces is still poorly understood and remains a subject of a great debate 18,[27][28][29][30][31] . The behavior of ions at interfaces is of great practical importance in such diverse fields as atmospheric chemistry, electrochemistry, colloidal science, biophysics, physical chemistry, etc.…”

Section: Hydrophobic Interfacesmentioning

confidence: 99%

Ions at hydrophobic interfaces

Levin

Santos

2014

J. Phys.: Condens. Matter

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We review the present understanding of the behavior of ions at the air-water and oil-water interfaces. We argue that while the alkali metal cations remain strongly hydrated and are repelled from the hydrophobic surfaces, the anions must be classified into kosmotropes and chaotropes. The kosmotropes remain strongly hydrated in the vicinity of a hydrophobic surface, while the chaotropes loose their hydration shell and can become adsorbed to the interface. The mechanism of adsorption is still a subject of debate. Here, we argue that there are two driving forces for anionic adsorption: the hydrophobic cavitational energy and the interfacial electrostatic surface potential of water. While the cavitational contribution to ionic adsorption is now well accepted, the role of the electrostatic surface potential is much less clear. The difficulty is that even the sign of this potential is a subject of debate, with the ab initio and the classical force fields simulations predicting electrostatic surface potentials of opposite sign. In this paper, we will argue that the strong anionic adsorption found in the polarizable force field simulations is the result of the artificial electrostatic surface potential present in the classical water models. We will show that if the adsorption of anions would be as large as predicted by the polarizable force field simulations, the excess surface tension of NaI solution would be strongly negative, contrary to the experimental measurements. While the large polarizability of heavy halides is a fundamental property and must be included in realistic modeling of the electrolytes solutions, we argue that the point charge water models, studied so far, are incompatible with the polarizable ionic force fields when the translational symmetry is broken. The goal for the future should be the development of water models with very low electrostatic surface potential. We believe that such water models will be compatible with the polarizable force fields and can then be used to study the interaction of ions with hydrophobic surfaces and proteins.

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Prediction of the concentration dependence of the surface tension and density of salt solutions: atomistic simulations using Drude oscillator polarizable and nonpolarizable models

Cited by 32 publications

References 91 publications

Fluid phase interface properties of acetone, oxygen, nitrogen and their binary mixtures by molecular simulation

Fluid phase interface properties of acetone, oxygen, nitrogen and their binary mixtures by molecular simulation

Ion clustering in aqueous salt solutions near the liquid/vapor interface

Ions at hydrophobic interfaces

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