Solvation Effects in Near-Critical Binary Mixtures

TL;DR

This paper develops a Ginzburg-Landau model to study how solvation effects and critical fluctuations influence charged particles in near-critical binary mixtures, revealing long-range electrostriction and ion-critical fluctuation coupling.

Contribution

It introduces a theoretical framework combining solvation, dielectric response, and critical phenomena in binary mixtures near the critical point.

Findings

Long-range Ornstein-Zernike tail in concentration profiles

Strong coupling between ions and critical fluctuations

Altered phase transition behavior due to solvation effects

Abstract

A Ginzburg-Landau theory is presented to investigate solvation effects in near-critical polar fluid binary mixtures. Concentration-dependence of the dielectric constant gives rise to a shell region around a charged particle within which solvation occurs preferentially. As the critical point is approached, the concentration has a long-range Ornstein-Zernike tail representing strong critical electrostriction. If salt is added, strong coupling arises among the critical fluctuations and the ions. The structure factors of the critical fluctuations and the charge density are calculated and the phase transition behavior is discussed.