Selective Solvation in Aqueous Mixtures: Interface Deformations and Instability

Ōnuki, Akira; Araki, Toshimitsu

doi:10.1143/jpsjs.81sa.sa004

Cited by 5 publications

(3 citation statements)

References 37 publications

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“…In Fig. 8, we also numerically examine the interface instability [25] with χ = 2.1 and g 1 = −g 2 = 12 in a cubic cell with length L = 64a. At t = 0, an interface was at z = L/2 and we added antagonistic ion pairs to the water side, where n i = 0.006v −1 0 for z > L/2 and n i = 0 for z < L/2.…”

Section: Interface Instabilitymentioning

confidence: 99%

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Structure formation due to antagonistic salts

Ōnuki

Yabunaka

Araki

et al. 2016

Current Opinion in Colloid & Interface Science

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Antagonistic salts are composed of hydrophilic and hydrophobic ions. In a mixture solvent (wateroil) such ion pairs are preferentially attracted to water or oil, giving rise to a coupling between the charge density and the composition. First, they form a large electric double layer at a water-oil interface, reducing the surface tension and producing mesophases. Here, the cations and anions are loosely bound by the Coulomb attraction across the interface on the scale of the Debye screening length. Second, on solid surfaces, hydrophilic (hydrophobic) ions are trapped in a water-rich (oilrich) adsorption layer, while those of the other species are expelled from the layer. This yields a solvation mechanism of local charge separation near a solid. In particular, near the solvent criticality, disturbances around solid surfaces can become oscillatory in space. In mesophases, we calculate periodic structures, which resemble those in experiments.

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Section: Interface Instabilitymentioning

confidence: 99%

“…FIG.8: Growth of interface deformations induced by antagonistic salt[25] in a box of length 64a at t/t0 = 500, 750, and 1000, where t0 = 2πa 3 η/kBT . The ion diffusion constant is D = a 2 /t0 for the two species.…”

mentioning

confidence: 99%

Structure formation due to antagonistic salts

Ōnuki

Yabunaka

Araki

et al. 2016

Current Opinion in Colloid & Interface Science

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“…The detailed morphology of the CDW structure was numerically examined by Araki and Onuki based on the Ginzburg-Landau theory [10,11,48,49]. In their model, large concentration fluctuation of solvents is taken into account, unlike in Figure 5.…”

Section: Charge-density-wave Structures Formed In Near-critical Regiomentioning

confidence: 99%

Membrane Formation in Liquids by Adding an Antagonistic Salt

Sadakane

Seto

2018

Front. Phys.

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Antagonistic salts are composed of hydrophilic and hydrophobic ions. In a binary mixture, such as water and organic solvent, these ion pairs preferentially dissolve to those phases, respectively, and there is a coupling between the charge density and the composition. The heterogeneous distribution of ions forms a large electric double layer at the interface between these solvents. This reduces the interfacial tension between water and organic solvent, and stabilizes an ordered structure, such as a membrane. These phenomena have been extensively studied from both theoretical and experimental point of view. In addition, the numerical simulations can reproduce such ordered structures.

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Impregnation and Swelling of Wood with Salts: Ion Specific Kinetics and Thermodynamics Effects

Barbetta

Fratzl

Zemb

et al. 2016

Adv Materials Inter

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The effects of salt impregnation are studied within wood cell walls, occurring upon soaking from concentrated salt solutions. Osmotic deswelling is in some cases followed by ion specific swelling linked to Hofmeister effects. Taking into account microstructure, this study models the free energy changes associated with the ions and water uptake at molecular, colloidal, and macroscopic mechanical scales, to show that slow swelling until osmotic equilibrium originates from charge separation of the salt diffused into wood cell wall material. Kinetic effects as well as mechanical effects linked to transfer of species and swelling of the interstitial matrix between cellulose crystals are discussed. Predictions by minimal models taking into account nonelectrostatic ion complexation allow to estimate the order of magnitude of the nonelectrostatic binding free energy of adsorbed chaotropic anions and complexed divalent cations to be 8 and 10 kJ mole–1, respectively

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Selective Solvation in Aqueous Mixtures: Interface Deformations and Instability

Cited by 5 publications

References 37 publications

Structure formation due to antagonistic salts

Structure formation due to antagonistic salts

Membrane Formation in Liquids by Adding an Antagonistic Salt

Impregnation and Swelling of Wood with Salts: Ion Specific Kinetics and Thermodynamics Effects

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