Salt-Induced Ordering in Lamellar Colloids
Salt-Induced Ordering in Lamellar Colloids
复制标题
层状胶体中盐诱导的有序化
作者：
D. Rowan;J. Hansen
不带电的棒和盘在增加密度时表现出向列相的各向同性相变。然而，在水溶液中，这样的粒子通常是高电荷的，导致排斥静电相互作用。本文研究了在单分散的薄带电胶盘溶液中加入盐的效果。微观盐离子的加入更有效地屏蔽了介观胶体颗粒之间的四极静电斥力，同时每个圆盘周围的双电层收缩。通过将每个圆盘及其相关的双层作为一个新的有效粒子来处理，研究了盐在稀悬液相图中的作用。
Uncharged rods and disks have long been known to exhibit an isotropic to nematic phase transition on increasing density. In aqueous solution, however, such particles are generally highly charged, leading to repulsive electrostatic interactions. In this article the effect of adding salt to a monodisperse solution of thin charged colloidal disks is examined. The addition of microscopic salt ions more efficiently screens the largely quadrupolar electrostatic repulsion between the mesoscopic colloidal particles, while at the same time the electric double layer around each disk contracts. By treating each disk with its associated double layer as a new effective particle, the role of salt on the phase diagram of dilute suspensions is investigated.