Dynamics of colloidal particles with capillary interactions
Dynamics of colloidal particles with capillary interactions
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DOI：
10.1103/physreve.82.011402
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发表时间：
2010-07-15
影响因子：
2.4
通讯作者：
Dietrich, S.
中科院分区：
文献类型：
--
作者：
Dominguez, Alvaro;Oettel, Martin;Dietrich, S.
我们研究了由吸引的毛细管相互作用驱动的流体界面处的胶体动力学。在亚毫米长度尺度上，毛细管吸引力在形式上类似于二维重力。特别是，它是一种不可积的相互作用，尽管它在对势水平上较弱，但它实际上可以与集体现象相关。我们引入了界面处粒子数密度动态演化的平均场模型。对于物理参数的通用值，发现均匀分布对于毛细管吸引力驱动的大规模聚类是不稳定的。我们还表明，为了观察到不稳定性，可以通过实验很好地获得相关参数（胶体半径、表面电荷、外部电场等）的适当值。我们的分析有助于当前对长程相互作用控制的系统的结构和动力学的研究，并指出它们通过胶体悬浮液的实验实现。
We investigate the dynamics of colloids at a fluid interface driven by attractive capillary interactions. At submillimeter length scales, the capillary attraction is formally analogous to two-dimensional gravity. In particular it is a nonintegrable interaction and it can be actually relevant for collective phenomena in spite of its weakness at the level of the pair potential. We introduce a mean-field model for the dynamical evolution of the particle number density at the interface. For generic values of the physical parameters the homogeneous distribution is found to be unstable against large-scale clustering driven by the capillary attraction. We also show that for the instability to be observable, the appropriate values for the relevant parameters (colloid radius, surface charge, external electric field, etc.) are experimentally well accessible. Our analysis contributes to current studies of the structure and dynamics of systems governed by long-ranged interactions and points toward their experimental realizations via colloidal suspensions.