液晶的彈性、旋性與表面錨定力是決定液晶的指向性，以及液晶被侷限在幾何形狀中所形成拓撲缺陷的重要因素。在本論文中，我們製備出懸掛在聚合物纖維上的膽固醇液晶微球，並觀察長螺距或短螺距的微球內部液晶分子受到外部刺激所產生排向變化與缺陷。在此系統中共存有兩種表面錨定力，分別是空氣與膽固醇微球界面處的垂直錨定力，以及聚合物纖維與膽固醇微球界面處的水平錨定力。
本論文的研究分成三個部分。在第一部分，我們觀察到膽固醇液晶微球從各向同性相冷卻到膽固醇相時內部液晶分子的形變過程與最後的平衡狀態，並提出物理模型解釋實驗結果。除了探討膽固醇微球的熱依賴性形變，這項研究的第二部分及第三部分還探討了摻雜偶氮液晶的膽固醇微球和摻雜偶氮手性材料的膽固醇微球對於光場的形變特性。藉由照射紫外光，由光引致偶氮材料的反式至順式異構化可在不改變溫度的情況下擾亂微球內液晶的排向，或是調整膽固醇液晶的螺距長度，進而改變微球內部的液晶分子排列方式及缺陷。由光照控制懸掛在聚合物纖維上的膽固醇液晶微球之內部形變，除了可用於遙控拓撲結構或操控奈米粒子在液晶裡的排列，也為軟物質拓樸結構元件的開發提供了一個新方向。

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.

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