Influence of alignment layer thickness on ferroelectric liquid-crystal structure

Abstract

We have investigated the influence of the thickness of polyvinyl alcohol alignment layer on azimuthal anchoring of ferroelectric liquid crystals by measuring the azimuthal angle of the chevron C2 structure. By varying not only the alignment but also the ferroelectric liquid-crystal layer thickness, we also studied the influence of the ions screening the polarization charge on the chevron layer structure. A simple model describing the free enthalpy of the system was used to calculate the anchoring coefficient from the azimuthal angle of the structure.

Controlling Light Emission in Luminescent Solar Concentrators Through Use of Dye Molecules Aligned in a Planar Manner by Liquid Crystals

“…The alignment layers often consist of a material, such as polyimide derivatives [15] or polyvinyl alcohol, [16] that is rubbed with a cloth to induce alignment in the liquid crystals. Typical alignment configurations that can be produced rather easily are: planar, [17] homeotropic, [18] splay, [19] tilted, [20,21] twisted nematic, [22] supertwisted nematic, [23] and chiral nematic.…”

Molecular Frustration of Chemically Linked Rod-Disc Liquid Crystal under an Electric Field

“…To improve electro-optic characteristics of liquid crystal displays (LCDs), design, synthesis, and characterization of complex LC molecules have been explored since the first discovery of LC materials in the 1880s. − Thanks to these efforts, LCD is a ubiquitous and superior display compared with others. − Parallel to the practical applications of LCs, novel LC phases such as twist grain boundary phases, − blue phases, − achiral banana phases − and biaxial nematic (N) LC phases − have been obtained by introducing different chemical functions as well as by synthesizing novel geometry of LC molecules. Among them, intensive researches on chemically connected rod-disk LC molecules have been focused on to fill the gap between discotic (disklike) and calamitic (rodlike) LCs and to examine the existence of biaxial N phase. − Unlike common rodlike LCs that exhibit uniaxial positive birefringence with the optic axis parallel to the molecular long axis, disklike LCs possess intrinsically uniaxial negative birefringence with the optic axis perpendicular to the disk-plane. − The competition between the excluded volumes of extremely different two mesogens in the chemically connected rod-disk LC molecules may result in a biaxial molecular orientation.…”