Abstract
We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference of the solvation chemical potential between liquid and gas Δμs (the Gibbs energy of transfer) is considerably larger than the thermal energy κBT for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by κBT n2ℓ exp(Δμs/kappa;BT), where n2ℓ is the solute density added in liquid. For exp(Δμs/κBT)≫1, phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, even when the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.
| Original language | English |
|---|---|
| Article number | 244012 |
| Journal | Journal of Physics Condensed Matter |
| Volume | 28 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - Apr 26 2016 |
| Externally published | Yes |
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Keywords
- nanobubble
- Phase separation in dilute binary mixtures
- solvation effect
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
Cite this
Density functional theory of gas-liquid phase separation in dilute binary mixtures. / Okamoto, Ryuichi; Onuki, Akira.
In: Journal of Physics Condensed Matter, Vol. 28, No. 24, 244012, 26.04.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Density functional theory of gas-liquid phase separation in dilute binary mixtures
AU - Okamoto, Ryuichi
AU - Onuki, Akira
PY - 2016/4/26
Y1 - 2016/4/26
N2 - We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference of the solvation chemical potential between liquid and gas Δμs (the Gibbs energy of transfer) is considerably larger than the thermal energy κBT for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by κBT n2ℓ exp(Δμs/kappa;BT), where n2ℓ is the solute density added in liquid. For exp(Δμs/κBT)≫1, phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, even when the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.
AB - We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference of the solvation chemical potential between liquid and gas Δμs (the Gibbs energy of transfer) is considerably larger than the thermal energy κBT for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by κBT n2ℓ exp(Δμs/kappa;BT), where n2ℓ is the solute density added in liquid. For exp(Δμs/κBT)≫1, phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, even when the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.
KW - nanobubble
KW - Phase separation in dilute binary mixtures
KW - solvation effect
UR - http://www.scopus.com/inward/record.url?scp=84969754340&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84969754340&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/28/24/244012
DO - 10.1088/0953-8984/28/24/244012
M3 - Article
AN - SCOPUS:84969754340
VL - 28
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 24
M1 - 244012
ER -