Surface tension and surface Δχ-potential of concentrated Z+:Z− electrolyte solutions

Slavchov, Radomir I.; Novev, Javor K.; Peshkova, Tatyana V.; Grozev, Nikolay A.

doi:10.1016/j.jcis.2013.04.038

Cited by 16 publications

(48 citation statements)

References 57 publications

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“…We do not compare with experimental surface potential changes since Slavchov et al [59] have shown that the presence of ions significantly alters the intrinsic surface potential of water, meaning that the potential created by the ionic distributions is not the only contribution to ∆χ. This means that experimental agreement cannot be expected.…”

Section: Experimental Datamentioning

confidence: 99%

Hydronium and hydroxide at the air–water interface with a continuum solvent model

Duignan

Parsons

Ninham

2015

Chemical Physics Letters

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The distribution of hydronium and hydroxide ions at the air-water interface has been a problem of much interest in recent years. Here we explore what insights can be gained from a continuum solvent model. We extend our model of ionic solvation free energies and surface interaction free energies to include hydronium and hydroxide. The hydronium cation is attracted to the air-water interface, whereas the hydroxide anion is repelled. If the cavity size parameters required by the model are adjusted to reproduce solvation energies, quantitative agreement with experimental surface tensions is achieved. To the best of our knowledge, this is the most accurate theoretical prediction of this property so far. The results indicate that even if 'water structure' is important, its effects can be captured with a relatively simple model. They also contradict the inference from electrophoresis that there is strong hydroxide enhancement at the air-water interface.

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Section: Experimental Datamentioning

confidence: 99%

Hydronium and hydroxide at the air–water interface with a continuum solvent model

Duignan

Parsons

Ninham

2015

Chemical Physics Letters

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“…These free energies determine the density distributions of ions in equilibrium, which in turn determine a huge range of important properties of electrolyte solution. For example, absolute p K a values, 1 and activity/osmotic coefficients 2 can be determined from ion–ion interaction free energies, whereas surface tensions, 3 surface forces, 4 colloidal/protein stability 5 and surface potentials 6 are directly related to ion–surface interaction free energies.…”

Section: Introductionmentioning

confidence: 99%

Real single ion solvation free energies with quantum mechanical simulation

et al. 2017

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“…Overlapping between the adsorbed layer and the diffuse dipole layer will be present, which must be dealt with similarly to the overlapping between the diffuse and the adsorbed electric layers near the charged surface of a concentrated electrolyte solution. 57 (iii) We present a macroscopic theory for a nano-object few ångstroms thick. Strong structural effects must be expected, which can be resolved by introducing levels of microscopic description.…”

Section: Discussionmentioning

confidence: 99%

“…As the analysis in supplementary material E 74 shows, the thickness h S of the surface layer of dipoles is of the same order of magnitude as L Q -since h S is a characteristic of the length of action of the specific interactions that orient the molecules (image forces, hydrogen bonds, van der Waals, steric forces), it can be even larger than L Q . Therefore, overlapping effect similar to the one observed in the electric double layer at high electrolyte concentrations 57,58 is inevitable. The bimodal distribution of the orientation of water molecules near the surface observed in simulations 15,16 corresponds, in the language of our work, to overlapping surface layer of moment P S z and oppositely oriented bulk layer with moment Γ W P .…”

Section: A the Contribution Of The Adsorbed Dipoles To The Interfacimentioning

confidence: 92%

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The polarized interface between quadrupolar insulators: Maxwell stress tensor, surface tension, and potential

Slavchov

Dimitrova

Ivanov

2015

The Journal of Chemical Physics

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The quadrupolar Maxwell electrostatic equations predict several qualitatively different results compared to Poisson's classical equation in their description of the properties of a dielectric interface. All interfaces between dielectrics possess surface dipole moment which results in a measurable surface potential jump. The surface dipole moment is conjugated to the bulk quadrupole moment density (the quadrupolarization) similarly to Gauss's relation between surface charge and bulk polarization. However, the classical macroscopic Maxwell equations completely neglect the quadrupolarization of the medium. Therefore, the electrostatic potential distribution near an interface of intrinsic dipole moment can be correctly described only within the quadrupolar macroscopic equations of electrostatics. They predict that near the polarized interface a diffuse dipole layer exists, which bears many similarities to the diffuse charge layer near a charged surface, in agreement with existing molecular dynamics simulation data. It turns out that when the quadrupole terms are kept in the multipole expansion of the laws of electrostatics, the solutions for the potential and the electric field are continuous functions at the surface. A well-defined surface electric field exists, interacting with the adsorbed dipoles. This allows for a macroscopic description of the surface dipole-surface dipole and the surface dipole-bulk quadrupole interactions. They are shown to have considerable contribution to the interfacial tension-of the order of tens of mN/m! To evaluate it, the Maxwell stress tensor in quadrupolar medium is deduced, including the electric field gradient action on the quadrupoles, as well as quadrupolar image force and quadrupolar electrostriction. The dependence of the interfacial tension on the external normal electric field (the dielectrocapillary curve) is predicted and the dielectric susceptibility of the dipolar double layer is related to the quadrupolarizabilities of the bulk phases and the intrinsic polarization of the interface. The coefficient of the dielectro-Marangoni effect (surface flow due to gradient of the normal electric field) is found. A model of the Langevin type for the surface dipole moment and the intrinsic surface polarizability is presented.

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Surface tension and surface Δχ-potential of concentrated Z+:Z− electrolyte solutions

Cited by 16 publications

References 57 publications

Hydronium and hydroxide at the air–water interface with a continuum solvent model

Hydronium and hydroxide at the air–water interface with a continuum solvent model

Real single ion solvation free energies with quantum mechanical simulation

The polarized interface between quadrupolar insulators: Maxwell stress tensor, surface tension, and potential

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