Fast Response and Spontaneous Alignment in Liquid Crystals Doped with 12-Hydroxystearic Acid Gelators

Abstract

The spontaneous vertical alignment of liquid crystals (LCs) in gelator (12-hydroxystearic acid)-doped LC cells was studied. Gelator-induced alignment can be used in both positive and negative LC cells. The electro-optical characteristics of the gelator-doped negative LC cell were similar to those of an LC cell that contained a vertically aligned (VA) host. The rise time of the gelator-doped LC cell was two orders of magnitude shorter than that of the VA host LC cell. The experimental results indicate that the gelator-induced vertical alignment of LC molecules occurred not only on the surface of the indium tin oxide (ITO) but also on the homogeneous alignment layer. Various LC alignments (planar, hybrid, multistable hybrid, and vertical alignments) were achieved by modulating the doped gelator concentrations. The multistable characteristic of LCs doped with the gelator is also presented. The alignment by doping with a gelator reduces the manufacturing costs and provides a means of fabricating fast-responding, flexible LC displays using a low-temperature process.

Gelation of Lyotropic Liquid-Crystal Phases—The Interplay between Liquid Crystalline Order and Physical Gel Formation

“…It has been shown that some organogelators are able to gel thermotropic liquid crystals (LCs), thus forming anisotropic soft solids. − The gel structure can enhance anisotropic properties such as electro-optical response in twisted nematic cells or hole mobility . Additionally, it is found that the gel network stabilizes the liquid-crystal (LC) alignment and director patterns. , If the liquid crystalline phase is formed before the gel network structure, the LC can serve as a soft template for the gel, resulting in well-aligned fibers. − If the fiber structure is formed first, randomly oriented fibers result in a polydomain LC morphology.…”