scholarly journals Spherical nematic shells with a prolate ellipsoidal core

Soft Matter ◽  
2017 ◽  
Vol 13 (41) ◽  
pp. 7465-7472 ◽  
Author(s):  
Monirosadat Sadati ◽  
Ye Zhou ◽  
Drew Melchert ◽  
Ashley Guo ◽  
Jose A. Martinez-Gonzalez ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Topological Defects ◽  
Ellipsoidal Particle ◽  
Spherical Core ◽  
Prolate Ellipsoidal

By replacing the inner spherical core of a radial liquid crystal shell with a planar prolate ellipsoidal particle, it is possible to form hybrid or twisted configurations, with topological defects positioned at the two ends of the ellipsoid.

A new pathway for the formation of radial nematic droplets within a lipid-laden aqueous-liquid crystal interface

RSC Advances ◽  
2014 ◽  
Vol 4 (36) ◽  
pp. 18889-18893 ◽  
Author(s):  
Sumyra Sidiq ◽  
Dibyendu Das ◽  
Santanu Kumar Pal
Keyword(s):  
Liquid Crystal ◽  
Topological Defects ◽  
Soft Materials ◽  
Stimuli Responsive ◽  
First Time ◽  
Crystal Interface

A new pathway for the formation of liquid crystal (LC) droplets with radial LC ordering is reported for the first time in the presence of surfactants and lipids. Interactions of an enzyme with the topological defects in the LC mediate the response of these droplets and thus provide new designs for stimuli-responsive soft materials.

scholarly journals Vortices Nucleation By Inherent Fluctuations In Nematic Liquid Crystal Cells

2021 ◽  
Author(s):  
Esteban Aguilera ◽  
Marcel G. Clerc ◽  
Valeska Zambra
Keyword(s):  
Liquid Crystal ◽  
Optical Tweezers ◽  
Nematic Liquid Crystal ◽  
Topological Defects ◽  
Optical Vortices ◽  
Topological Features ◽  
Nucleation Mechanisms ◽  
Multistable Systems ◽  
Light Beams ◽  
Crystal Cells

Abstract Multistable systems are characterized by exhibiting domain coexistence, where each domain accounts for the different states. In the case of these systems are described by vectorial fields, domains are connected through topological defects. Vortices are one of the most frequent and studied topological defect points. Optical vortices are equally relevant for their fundamental features as beams with topological features and their applications in image processing, telecommunications, optical tweezers, and quantum information. The interaction of light beams with matter vortices in liquid crystal cells is a natural source of optical vortices. The rhythms that govern the emergence of matter vortexes due to fluctuations are not established. Here we investigate the nucleation mechanisms of the matter vortices in liquid crystal cells and establish statistical laws that govern them. Based on a stochastic amplitude equation, the law for the number of nucleated vortices as a function of anisotropy, voltage, and noise level intensity is set. Experimental observations in a nematic liquid crystal cell with homeotropic anchoring and a negative anisotropic dielectric constant under the influence of a transversal electric field show a fair agreement with the theoretical findings.

scholarly journals Tunable two-dimensional polarization grating using a self-organized micropixelated liquid crystal structure

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41472-41479 ◽  
Author(s):  
Reo Amano ◽  
Péter Salamon ◽  
Shunsuke Yokokawa ◽  
Fumiaki Kobayashi ◽  
Yuji Sasaki ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Topological Defects ◽  
Self Organization ◽  
Two Dimensional ◽  
Self Organized ◽  
Optical Grating ◽  
Liquid Crystal Structure ◽  
Polarization Grating

A micro-pixelated pattern of a nematic liquid crystal formed by self-organization of topological defects is shown to work as a tunable two-dimensional optical grating.

scholarly journals Topology control of human fibroblast cells monolayer by liquid crystal elastomer

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz6485 ◽  
Author(s):  
Taras Turiv ◽  
Jess Krieger ◽  
Greta Babakhanova ◽  
Hao Yu ◽  
Sergij V. Shiyanovskii ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Orientational Order ◽  
Topological Defects ◽  
Density Fluctuations ◽  
Dermal Fibroblasts ◽  
Produce Cell ◽  
Surface Anchoring ◽  
Liquid Crystal Elastomer ◽  
Anisotropic Surface ◽  
Living Tissues

Eukaryotic cells in living tissues form dynamic patterns with spatially varying orientational order that affects important physiological processes such as apoptosis and cell migration. The challenge is how to impart a predesigned map of orientational order onto a growing tissue. Here, we demonstrate an approach to produce cell monolayers of human dermal fibroblasts with predesigned orientational patterns and topological defects using a photoaligned liquid crystal elastomer (LCE) that swells anisotropically in an aqueous medium. The patterns inscribed into the LCE are replicated by the tissue monolayer and cause a strong spatial variation of cells phenotype, their surface density, and number density fluctuations. Unbinding dynamics of defect pairs intrinsic to active matter is suppressed by anisotropic surface anchoring allowing the estimation of the elastic characteristics of the tissues. The demonstrated patterned LCE approach has potential to control the collective behavior of cells in living tissues, cell differentiation, and tissue morphogenesis.

scholarly journals Effects of flow on topological defects in a nematic liquid crystal near a colloid

2014 ◽  
Vol 140 (5) ◽  
pp. 054905 ◽  
Author(s):  
Tillmann Stieger ◽  
Martin Schoen ◽  
Marco G. Mazza
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Topological Defects

scholarly journals Light-activated helical inversion in cholesteric liquid crystal microdroplets

2018 ◽  
Vol 115 (17) ◽  
pp. 4334-4339 ◽  
Author(s):  
Piotr Sleczkowski ◽  
Ye Zhou ◽  
Supitchaya Iamsaard ◽  
Juan J. de Pablo ◽  
Nathalie Katsonis ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Molecular Motor ◽  
Cholesteric Liquid Crystal ◽  
Topological Defects ◽  
Alternative Activation ◽  
Droplet Radius ◽  
Bipolar Structure ◽  
Photostationary State ◽  
Topological Features ◽  
Shed Light

Cholesteric liquid crystal (CLC) droplets exhibit nontrivial topological features, which are controlled by the ratio between the cholesteric pitch and the droplet radius. The radial spherical structure (RSS) is of particular interest, as it reveals an onion-like concentric organization of the cholesteric helices, leading to the expression of spherical Bragg microcavities. Using an overcrowded alkene-based unidirectional molecular motor as a dopant, we show that the topological defect structure in the droplet can be activated by illumination. By using appropriate molecular motor concentrations, light can either break the symmetry of topological defects (as observed for the bent-twisted bipolar structure), or it can induce inversion of handedness in an onion-like organization (in the case of RSS). This latter feature may pave the way toward alternative activation modes of lasers based on cholesteric droplets. By also studying CLC droplets once they have reached full photoconversion at photostationary state (PSS), we highlight that the strong influence of confinement on the droplets structure occurs to the same extent after the helix inversion event. Our results are interpreted in terms of numerical simulations of the droplets’ structure, which shed light on the major role played by curvature close to the droplets’ center, this latter one becoming dominant when the droplet radius is small.

scholarly journals Prolate and oblate chiral liquid crystal spheroids

2020 ◽  
Vol 6 (28) ◽  
pp. eaba6728
Author(s):  
Monirosadat Sadati ◽  
Jose A. Martinez-Gonzalez ◽  
Ye Zhou ◽  
Nader Taheri Qazvini ◽  
Khia Kurtenbach ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Wearable Sensors ◽  
Mechanical Strain ◽  
Orientational Order ◽  
Topological Defects ◽  
Smart Fabrics ◽  
Chiral Liquid Crystal ◽  
Smart Coatings ◽  
Optical Appearance

Liquid crystals are known to exhibit intriguing textures and color patterns, with applications in display and optical technologies. This work focuses on chiral materials and examines the palette of morphologies that arises when microdroplets are deformed into nonspherical shapes in a controllable manner. Specifically, geometrical confinement and mechanical strain are used to manipulate orientational order, phase transitions, and topological defects that arise in chiral liquid crystal droplets. Inspired by processes encountered in nature, where insects and animals often rely on strain and temperature to alter the optical appearance of dispersed liquid crystalline elements, chiral droplets are dispersed in polymer films and deformation induced by uniaxial or biaxial stretching. Our measurements are interpreted by resorting to simulations of the corresponding systems, thereby providing an in-depth understanding of the morphologies that arise in these materials. The reported structures and assemblies offer potential for applications in smart coatings, smart fabrics, and wearable sensors.

Topological Defects in Liquid Crystal Films

2007 ◽  
Vol 47 (6) ◽  
pp. 1125-1128
Author(s):  
Duan Yi-Shi ◽  
Zhao Li ◽  
Zhang Xin-Hui ◽  
Si Tie-Yan
Keyword(s):  
Liquid Crystal ◽  
Topological Defects ◽  
Liquid Crystal Films ◽  
Crystal Films
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