Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf, Germany.
Soft Matter. 2017 Nov 15;13(44):8120-8135. doi: 10.1039/c7sm01704a.
The impact of topology on the structure of a smectic monolayer confined to a sphere is explored by particle-resolved computer simulations of hard rods. The orientations of the particles are tangential to the sphere and either free or restricted to a prescribed director field with a latitude or longitude orderings. Depending on the imprinted topology, a wealth of different states are found including equatorial smectic with isotropic poles, equatorial smectic with empty poles, a broken egg-shell like modulated smectic, a capped nematic with equatorial bald patches, equatorial nematic with empty poles, and a situation with 4 or 8 half-strength topological defects. Potentially these states could be verified in experiments with Pickering emulsions of droplets with colloidal rods. The unique nature of dipolar structures consisting of positive and negative half-strength disclinations is revealed. These structures, classified by their density and interaction with other defects in the system, relieve the strain of the poles by separating closely positioned half-strength defects. The proximity of these structures to the half-strength defects might enhance the structural diffusion of the defects across the system.
通过对硬棒的粒子分辨计算机模拟，研究了拓扑结构对受限在球体中的 smectic 单层结构的影响。粒子的取向与球体相切，并且可以自由或限制在具有纬度或经度排序的预定指向场中。根据所印拓扑的不同，可以发现包括具有各向同性极的赤道 smectic、具有空极的赤道 smectic、呈破碎蛋壳状的调制 smectic、具有赤道光秃区的 capped nematic、具有空极的赤道 nematic 以及具有 4 或 8 个半强度拓扑缺陷的情况。这些状态可能可以通过带有胶体棒的 Pickering 乳液滴实验来验证。揭示了由正和负半强度不连续性组成的偶极子结构的独特性质。这些结构根据其密度和与系统中其他缺陷的相互作用进行分类，可以通过分离紧密定位的半强度缺陷来缓解极的应变。这些结构与半强度缺陷的接近可能会增强缺陷在整个系统中的结构扩散。
