Precipitation in aqueous mixtures with addition of strongly hydrophilic or hydrophobic solute

Abstract

We examine phase separation in aqueous mixtures due to preferential solvation with a low-density solute (hydrophilic ions or hydrophobic particles). For hydrophilic ions, preferential solvation can stabilize water domains enriched with ions. This precipitation occurs in wide ranges of the temperature and the average composition above a critical solute density $n_p$, where the mixture solvent would be in a one-phase state without solute. The volume fraction of precipitated domains tends to zero as the average solute density $\bar{n}$ is decreased to $n_p$ or as the interaction parameter $\chi$ is decreased to a critical value ${\chi }_p$. If we start with one-phase states with $\bar{n}>n_p$ or $\chi >{\chi }_p$, precipitation proceeds via homogeneous nucleation or via heterogeneous nucleation, for example, around suspended colloids. In the latter case, colliod particles are wrapped by thick wetting layers. We also predict a first-order prewetting transition for $\bar{n}$ or $\chi$ slightly below $n_p$ or ${\chi }_p$.

19 pages, 18 figures

References in corpus (3)

• Surface tension of electrolytes: Hydrophilic and hydrophobic ions near an interface
• Nonionic and ionic surfactants at an interface
• Phase-Separation Transition in Liquid Mixtures Near Charged Objects

Cited by in corpus (18)

• Charged colloids in an aqueous mixture with a salt
• Attractive interaction and bridging transition between neutral colloidal particles due to preferential adsorption in a near-critical binary mixture
• Local theory for ions in binary liquid mixtures
• Attraction Between Like-Charge Surfaces in Polar Mixtures
• Solvation Effects in Phase Transitions in Soft Matter
• The interaction between colloids in polar mixtures above Tc
• Theory of nonionic hydrophobic solutes in mixture solvent: Solvent-mediated interaction and solute-induced phase separation
• Theory of electrolytes including steric, attractive, and hydration interactions
• Microphase separation in oil-water mixtures containing hydrophilic and hydrophobic ions
• Pre-dewetting transition on a hydrophobic wall: Statics and dynamics
• Electrophoresis of electrically neutral porous spheres induced by selective affinity of ions
• Reversible Pore Gating in Aqueous Mixtures via External Potential
• Density functional theory of gas-liquid phase separation in dilute binary mixtures
• Isothermal transport of a near-critical binary fluid mixture through a capillary tube with the preferential adsorption
• Effects of strongly selective additives on volume phase transition in gels
• Selective solvation in aqueous mixtures: Interface deformations and instability
• Fluctuating hydrodynamics of dilute electrolyte solutions: systematic perturbation calculation of effective transport coefficients governing large-scale dynamics
• Recent advances in liquid mixtures in electric fields