Annunziata Onofrio
Department of Chemistry and Biochemistry, Texas Christian University, 2950 W. Bowie St., Sid Richardson Bldg. #438, Fort Worth, TX 76109, USA.
Molecules. 2024 Mar 19;29(6):1367. doi: 10.3390/molecules29061367.
Diffusiophoresis is the isothermal migration of a colloidal particle through a liquid caused by a cosolute concentration gradient. Although diffusiophoresis was originally introduced using hydrodynamics, it can also be described by employing the framework of multicomponent diffusion. This not only enables the extraction of diffusiophoresis coefficients from measured multicomponent-diffusion coefficients but also their theoretical interpretation using fundamental thermodynamic and transport parameters. This review discusses the connection of diffusiophoresis with the 2 × 2 diffusion-coefficient matrix of ternary liquid mixtures. Specifically, diffusiophoresis is linked to the cross-term diffusion coefficient characterizing diffusion of colloidal particles due to cosolute concentration gradient. The other cross-term, which describes cosolute diffusion due to the concentration gradient of colloidal particles, is denoted as osmotic diffusion. Representative experimental results on diffusiophoresis and osmotic diffusion for polyethylene glycol and lysozyme in the presence of aqueous salts and osmolytes are described. These data were extracted from ternary diffusion coefficients measured using precision Rayleigh interferometry at 25 °C. The preferential-hydration and electrophoretic mechanisms responsible for diffusiophoresis are examined. The connection of diffusiophoresis and osmotic diffusion to preferential-interaction coefficients, Onsager reciprocal relations, Donnan equilibrium and Nernst-Planck equations are also discussed.
扩散泳是指胶体粒子在液体中由于共溶质浓度梯度而进行的等温迁移。虽然扩散泳最初是从流体动力学角度引入的，但也可以用多组分扩散的框架来描述。这不仅能从测量得到的多组分扩散系数中提取扩散泳系数，还能利用基本的热力学和输运参数对其进行理论解释。本综述讨论了扩散泳与三元液体混合物的2×2扩散系数矩阵之间的联系。具体而言，扩散泳与表征由于共溶质浓度梯度导致的胶体粒子扩散的交叉项扩散系数相关。另一个交叉项，即描述由于胶体粒子浓度梯度导致的共溶质扩散的交叉项，被称为渗透扩散。文中描述了在含水盐和渗透剂存在的情况下，聚乙二醇和溶菌酶的扩散泳和渗透扩散的代表性实验结果。这些数据是从25℃下使用精密瑞利干涉测量法测得的三元扩散系数中提取的。文中研究了导致扩散泳的优先水合和电泳机制。还讨论了扩散泳和渗透扩散与优先相互作用系数、昂萨格互易关系、唐南平衡和能斯特 - 普朗克方程之间的联系。
