Ohshima Hiroyuki
Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
Micromachines (Basel). 2025 Feb 26;16(3):266. doi: 10.3390/mi16030266.
A general theory is presented to analyze the time-dependent, transient diffusiophoresis of a charged spherical colloidal particle in an uncharged gel medium containing a symmetrical electrolyte when an electrolyte concentration gradient is suddenly applied. We derive the inverse Laplace transform of an approximate expression for the relaxation function (), which describes the time-course of the ratio of the diffusiophoretic mobility of a weakly charged spherical colloidal particle, possessing a thin electrical double layer, to its steady-state diffusiophoretic mobility. The relaxation function depends on the mass density ratio of the particle to the electrolyte solution, the particle radius, the Brinkman screening length, and the kinematic viscosity. However, it does not depend on the type of electrolyte (e.g., KCl or NaCl), which affects only the steady-state gel diffusiophoretic mobility. It is also found that the expression for the relaxation function in transient gel diffusiophoresis of a weakly charged spherical colloidal particle with a thin electrical double layer takes the same form as that for its transient gel electrophoresis.
本文提出了一种通用理论，用于分析当突然施加电解质浓度梯度时，带电球形胶体粒子在含有对称电解质的不带电凝胶介质中的时间相关瞬态扩散泳动。我们推导了弛豫函数(\varPhi(t))近似表达式的拉普拉斯逆变换，该弛豫函数描述了具有薄电双层的弱带电球形胶体粒子的扩散泳动迁移率与其稳态扩散泳动迁移率之比随时间的变化过程。弛豫函数取决于粒子与电解质溶液的质量密度比、粒子半径、布林克曼屏蔽长度和运动粘度。然而，它不依赖于电解质的类型（例如KCl或NaCl），电解质类型仅影响稳态凝胶扩散泳动迁移率。还发现，具有薄电双层的弱带电球形胶体粒子在瞬态凝胶扩散泳动中弛豫函数的表达式与其瞬态凝胶电泳的表达式具有相同的形式。
