Phase Transitions in Soft Matter Induced by Selective Solvation

Ōnuki, Akira; Okamoto, Ryuichi; Araki, Toshimitsu

doi:10.1246/bcsj.20110012

Cited by 36 publications

(78 citation statements)

References 108 publications

(212 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In liquid water in contact with a hydrophobic surface, water molecules tend to be separated from the surface due to the hydrogen bonding among the water molecules, resulting in the formation of a gaseous layer on the surface 5 . In aqueous mixtures with salt, prewetting behavior is much intensified by the composition-dependent surface ionization and the preferential solvation of ions [6][7][8] . In these examples, heterogeneities in the density or the composition are induced near the wall, often resulting in wetting or drying transition on the wall.…”

Section: Introductionmentioning

confidence: 99%

Casimir amplitudes and capillary condensation of near-critical fluids between parallel plates: Renormalized local functional theory

Okamoto

Ōnuki

2012

The Journal of Chemical Physics

Self Cite

120

View full text Add to dashboard Cite

We investigate the critical behavior of a near-critical fluid confined between two parallel plates in contact with a reservoir by calculating the order parameter profile and the Casimir amplitudes (for the force density and for the grand potential). Our results are applicable to one-component fluids and binary mixtures. We assume that the walls absorb one of the fluid components selectively for binary mixtures. We propose a renormalized local functional theory accounting for the fluctuation effects. Analysis is performed in the plane of the temperature T and the order parameter in the reservoir ψ∞. Our theory is universal if the physical quantities are scaled appropriately. If the component favored by the walls is slightly poor in the reservoir, there appears a line of first-order phase transition of capillary condensation outside the bulk coexistence curve. The excess adsorption changes discontinuously between condensed and noncondensed states at the transition. With increasing T , the transition line ends at a capillary critical point T = T ca c slightly lower than the bulk critical temperature Tc. The Casimir amplitudes are larger than their critical-point values by 10-100 times at off-critical compositions near the capillary condensation line.

show abstract

Section: Introductionmentioning

confidence: 99%

Casimir amplitudes and capillary condensation of near-critical fluids between parallel plates: Renormalized local functional theory

Okamoto

Ōnuki

2012

The Journal of Chemical Physics

Self Cite

120

View full text Add to dashboard Cite

show abstract

“…(i) Near the critical point, a mixture solvent is very sensitive to selective impurities such as ions which interact with each solvent species asymmetrically. [30][31][32] Theoretical works have shown that even a small amount of salt can play a significant role in the static behavior of the adsorption layer. [33][34][35] The ion effect on the drag coefficient would be significant in experiments.…”

Section: Discussionmentioning

confidence: 99%

Drag Coefficient of a Rigid Spherical Particle in a Near-Critical Binary Fluid Mixture

2013

Self Cite

View full text Add to dashboard Cite

We calculate the drag coefficient of a rigid spherical particle in an incompressible binary fluid mixture. A weak preferential attraction is assumed between the particle surface and one of the fluid components, and the difference in the viscosity between the two components is neglected. Using the Gaussian free-energy functional and solving the hydrodynamic equation explicitly, we can show that the preferential attraction makes the drag coefficient larger as the bulk correlation length becomes longer. The dependence of the deviation from the Stokes law on the correlation length, when it is short, turns out to be much steeper than the previous estimates.

show abstract

“…Then g i > 0 for hydrophilic ions and g i < 0 for hydrophobic ions. For strongly hydrophilic ions, μ i sol (φ) should decrease very steeply in a concentration range 0 < φ < φ i sol , where hydration shells are formed [4]. Here φ i sol ∼ 0.002 for Br − in water-nitrobenzene.…”

Section: Introductionmentioning

confidence: 99%

“…Jpn. 81 (2012) SA004 SA004-2 coexistence curve [11,12], and (iii) mesophase formation in aqueous mixtures for an antagonistic salt [2][3][4][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selective Solvation in Aqueous Mixtures: Interface Deformations and Instability

Ōnuki

Araki

2012

J. Phys. Soc. Jpn.

Self Cite

View full text Add to dashboard Cite

We briefly review the effects of selective solvation of ions in aqueous mixtures, where the ion densities and the composition fluctuations are strongly coupled. We then examine the surface tension γ of a liquid-liquid interface in the presence of ions. We show that γ can be decreased drastically due to the electrostatic and solvation interactions near the interface. We calculate how the free energy is changed due to small surface undulations in the presence of an electric double layer. A surface instability occurs for negative γ, which can easily be realized for antagonistic ion pairs near the solvent criticality. Three-dimensional simulation shows how the surface instability is induced.

show abstract

Phase Transitions in Soft Matter Induced by Selective Solvation

Cited by 36 publications

References 108 publications

Casimir amplitudes and capillary condensation of near-critical fluids between parallel plates: Renormalized local functional theory

Casimir amplitudes and capillary condensation of near-critical fluids between parallel plates: Renormalized local functional theory

Drag Coefficient of a Rigid Spherical Particle in a Near-Critical Binary Fluid Mixture

Selective Solvation in Aqueous Mixtures: Interface Deformations and Instability

Contact Info

Product

Resources

About