Preparation Of Flexible Cholesteric Liquid Crystal Display By Microencapsulation Of Liquid Crystal

Flexible display devices are in a preliminary stage in comparison with rigid flatdisplay devices which have been studied for many years and widely applied in thedisplay industry. Reflective displays based on cholesteric liquid crystals (CLC) haveattracted much attention due to their pure reflective nature, bistability, low powerconsumption, high brightness and contrast. Monodispersed cholesteric liquid crystalmicrocapsules with high core loadings and excellent reflective properties are the keyto the preparation of reflective liquid crystal displays. This thesis investigated thepreparation of microencapsulation processes of cholesteric liquid crystals and theirapplication in reflective display devices based on cholesteric liquid crystals.The CLC/CBU microcapsules were prepared first by the Solvent Induced PhaseSeparation(SIPS)-Photopolymerization. The morphology, reflective property, coreloading and size distribution were analysed and discussed. The optimum parametershave been obtained, including the reaction temperature and stirring rate. Thedeformable microcapsules with high core loading and excellent reflective propertywere obtained. In order to enhance the sealing property, the double-wallmicrocapsules were prepared by coacervation. The shell-gelltin-arabic could enhancethe sealing of CLC/CBU microcapsules while the deformation was excellent.Appropriate protective colloids and surfactant were added to adjust the viscosityand surface tension of cholesteric liquid crystal microcapsule coatings, thereforesuitable for film preparation on the ITO-PET (IndiumTinOxide-polyethylene terephthalate)film. Compact and uniform coatings are obtained via appropriate coating method. Theresults showed that the protective colloids and surfactant were very important toachieve the compact and uniform films.The suitable preparation parameters for display-sealant, blinder and coatingmethod were optimized and the reflective Cholesteric Liquid Crystal DisplaysChLCD with bistablity and excellent reflective property were prepared. Theelectrical properties, flexibility and fatigue durability were characterized. When thethickness of rigid and flexible displays is10μm, the driving voltage is40V and50V.The effective display area is5×5cm2.