Colloid-wall interaction in a nematic liquid crystal: the mirror-image method of colloidal nematostatics.
Colloid-wall interaction in a nematic liquid crystal: the mirror-image method of colloidal nematostatics.
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向列液晶中的胶体壁相互作用：胶体向列静学的镜像方法。
DOI：
10.1103/physreve.79.021704
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
V. Uzunova
中科院分区：
文献类型：
--
作者：
V. Pergamenshchik;V. Uzunova
胶体静电学和静电学之间富有成效的类比极大地指导了胶体系统（或胶体乳剂）的新领域。胶体线虫抑制剂的弹性电荷密度表示[V.M. Pergamenshchik和V.O. Uzunova，欧洲Phys.J.E23，161（2007）; Phys.Rev.E76，011707（2007）]在电荷密度和库仑相互作用的水平上发展了这种类比。然而，三维胶体线虫静力学在数学结构和物理意义上与静电学有本质区别：弹性电荷和多极子是对偶的;相似的电荷相互吸引，相反的电荷相互排斥，本文考虑了弹性电荷与弹性偶极子的相互作用，其中弹性偶极子的作用面是一个平面（壁面）指向矢对准固定在该位置。以静电学中的镜像方法为指导思想，发展了任意指向矢倾斜的静电学中的镜像方法。一个墙被示出，以诱导排斥1 R {4}力的弹性偶极子，在一般情况下，是伴随着它的重定向。作用在胶体上的外力会在其中产生一个弹性电荷，并触发向1 R {2}排斥的转换。弹性偶极子的并矢性质被证明是必不可少的：一个粒子壁相互作用势不能得到一个单一的组件偶极子的唯象理论。在引言部分，我们讨论了导演介导的相互作用在二维和三维之间的连接和静电相互作用，并考虑不同的对称性的弹性偶极子。施加在胶体上的扭矩分量的守恒被证明发挥高斯定理的作用，并确定弹性电荷二分力。
The new area of nematic colloidal systems (or nematic emulsions) has been greatly guided by the fruitful analogy between the colloidal nematostatics and electrostatics. The elastic charge density representation of the colloidal nematostatics [V. M. Pergamenshchik and V. O. Uzunova, Eur. Phys. J. E 23, 161 (2007); Phys. Rev. E 76, 011707 (2007)] develops this analogy at the level of charge density and Coulomb interaction. It shows, however, that the colloidal nematostatics in three dimensions substantially differs from the electrostatics both in its mathematical structure and physical implications: the elastic charge and multipoles are dyads; similar charges attract while opposite charges repel each other, and so on. In this paper we consider the interaction between an elastic charge and elastic dipole with a nematic surface (wall) at which the director alignment is fixed. Using the mirror image method of electrostatics as a guiding idea, we develop the mirror image method in the nematostatics for arbitrary director tilt at the wall. A wall is shown to induce a repulsive 1R{4} force on the elastic dipole which, in general, is accompanied by its reorientation. External torque on the colloid induces an elastic charge therein and triggers switching to the 1R{2} repulsion. The dyadic nature of an elastic dipole is shown to be essential: a particle-wall interaction potential cannot be obtained in phenomenological theories with a single component dipole. In the introductory sections we discuss connection between the director-mediated interaction in two and three dimensions and the electrostatic interaction and consider different symmetries of elastic dipoles. Conservation of the torque components exerted upon colloids is shown to play the role of Gauss' theorem and determines the elastic charge dyad.