Statics and dynamics of point boojums, line and modified Saturn ring topological defects in nematic confined geometry

IF 1.8 4区物理与天体物理 Q4 CHEMISTRY, PHYSICAL The European Physical Journal E Pub Date : 2023-12-07 DOI:10.1140/epje/s10189-023-00387-3

P. V. Dolganov, N. A. Spiridenko, V. K. Dolganov

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Abstract

In this paper we study the static structure and the dynamics of topological defects associated with isotropic droplets in nematic environment. Investigations were made in confined geometry of optical cells when the droplet size was of the order of or larger than the gap of the cell. We observed the coexistence of point boojums and Saturn ring or modified Saturn ring defects. We found transformation of the Saturn ring defect to two localized broad defects at increasing the droplet size. At droplet coalescence antipodes of point and localized broad defects were born and the dynamics of their annihilation with existing defects was investigated. We found strong difference in the process of annihilation of point and localized broad defects.

Graphical Abstract

Microscope images of isotropic droplets in nematic environment in a planar cell. The director orientation far from the droplets is in horizontal direction. The photographs were taken with crossed vertical and horizontal polarizers (a) and with a single horizontal polarizer (b). The cell thickness is 100 μm. Droplet diameter is less than the cell thickness. 1 and 2 are point boojums, L is the Saturn ring defect

Abstract Image

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向列受限几何中点boojums、线和修正土星环拓扑缺陷的静力学和动力学。

本文研究了向列环境中各向同性液滴拓扑缺陷的静态结构和动力学特性。当液滴大小等于或大于细胞间隙时，在光学细胞的受限几何结构中进行了研究。我们观察到点boojums和土星环或改进的土星环缺陷共存。我们发现随着液滴尺寸的增大，土星环缺陷转变为两个局部的宽缺陷。在液滴聚结时产生了点缺陷和局部宽缺陷的对映体，并研究了它们与现有缺陷湮灭的动力学。我们发现点的湮灭过程与局部宽缺陷的湮灭过程有很大的不同。平面细胞向列环境中各向同性液滴的显微镜图像。远离液滴的方向为水平方向。照片采用垂直和水平交叉偏振片(a)和单个水平偏振片(b)拍摄，电池厚度为100 μm。液滴直径小于细胞厚度。1和2是点boojums, L是土星环缺陷。

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来源期刊

The European Physical Journal E CHEMISTRY, PHYSICAL-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

2.60

自引率

5.60%

发文量

审稿时长

3 months

期刊介绍： EPJ E publishes papers describing advances in the understanding of physical aspects of Soft, Liquid and Living Systems. Soft matter is a generic term for a large group of condensed, often heterogeneous systems -- often also called complex fluids -- that display a large response to weak external perturbations and that possess properties governed by slow internal dynamics. Flowing matter refers to all systems that can actually flow, from simple to multiphase liquids, from foams to granular matter. Living matter concerns the new physics that emerges from novel insights into the properties and behaviours of living systems. Furthermore, it aims at developing new concepts and quantitative approaches for the study of biological phenomena. Approaches from soft matter physics and statistical physics play a key role in this research. The journal includes reports of experimental, computational and theoretical studies and appeals to the broad interdisciplinary communities including physics, chemistry, biology, mathematics and materials science.