56.2: Invited Paper: Novel Bistable Liquid Crystal Materials for AR/VR Technology, Vehicle and Flexible Display

Abstract

The object of study is chiral-nematic and smectic A liquid crystals. The aim of the work is to develop new bistable materials with improved physico-chemical and electro-optical properties for various applications. Chiral liquid-crystalline compounds and compounds characterized by the presence of the smectic A phase over a wide temperature range were synthesized during the studies. The influence of the viscoelastic properties of liquid crystals, the anchoring energy of the alignment material, and the helical twisting power of chiral dopants on the memory effect in chiral-nematic liquid crystals was investigated. In order to clarify the possible mechanism of bistability in highly twisted nematics, we performed a numerical simulation of the reorientation of liquid crystal molecules in an electric field. It was also necessary to find out which parameters of the liquid crystal material have the greatest effect on the bistability. Based on the synthesized smectic compounds, mixtures with different values of optical anisotropy and viscosity were developed. The influence of the compounds structure (bridge fragments, polar groups, alkyl chains) on mesomorphic and basic physico-chemical characteristics was determined. Electrically and electrochemically stable ion dopants were also synthesized with a number of organic cations and organic/inorganic anions. The composition of mixtures has been optimized for long-term operation, especially in the upper operating temperature range.