Morphology and defect of cholesteric liquid crystal microdroplets suspending on microfibres

Abstract

The orientation of liquid crystals (LC) and the formation of topological defects of LCs in confined geometries are determined by nematic elasticity chirality and surface anchoring In this study we report the deformations of the inner orientation in cholesteric LC (CLC) microdroplets with short- and long-pitch deposits on polymeric fibers Two kinds of surface anchoring namely perpendicular anchoring at the air–CLC droplet interface and planar anchoring at the fiber–CLC droplet interface coexist in this system This thesis is divided into three parts In the first part we observed the equilibrium structures of the CLC microdroplets that were thermally cooled down from isotropic phase to chiral nematic phase The alignment model of LC molecules under temperature change is proposed The second and third parts of this study discuss the photo-dependent deformations of the azo-CLC microdroplets which are composed of azo-LC-doped CLCs or azo-chiral-doped CLCs UV irradiation-induced trans to cis isomerization of the azo-materials can disturb the orientations of the LCs and thus the isothermal phase transition or the pitch variations of the CLCs inside the microdroplets resulting in inner deformations and alterations of the disclinations in the microdroplets The photo-controlled deformations and defects of the CLC microdroplets on polymeric fibers presented in this work can not only be used to achieve topological remote control but can also be applied in nanoscience and biomedical studies as well as in developing devices based on topologically structured soft media

Date of Award	2017 Feb 13
Original language	English
Supervisor	Chia-Rong Lee (Supervisor)