Characterization of Some Fluorinated Mesogens for Application in Liquid Crystal Displays

Abstract

The long-range orientational order of some fluoro-substituted liquid crystals with different molecular structure was determined on the basis of the optical birefringence measurements. The high values of the second-rank order parameter in the whole mesophase range for the liquid crystals studied were found. The liquid crystals with the negative dielectric anisotropy were mixed with an arachidic acid at various molar fractions. The behavior of the mixtures in monolayers formed by using Langmuir-Blodgett technique was investigated.

The Langmuir-Blodgett Technique as a Tool for Homeotropic Alignment of Fluorinated Liquid Crystals Mixed with Arachidic Acid

“…Therefore, after the transfer of the floating monolayer of the liquid crystal/AA mixture at low surface pressure (π = 6 mN/m for 8OCFPB and 2 mN/m for N54) the molecules are not densely packed and as a result the long axes of the liquid crystal molecules are tilted with respect to the quartz surface, which is reflected in distinct absorbance of the LB film. In our previous paper [ 32 ] we supposed that at π = 20 mN/m, when the molecules are strongly compressed, they align perfectly perpendicular and the projection of the absorption transition moment on the surface decreases, leading to the absorbance diminishing. However, the analysis of the π-A isotherms and BAM images, described in previous section, contradicts this assumption.…”

Low-Mass Liquid Crystalline Materials Blended in Recycled Thermoplastic Polyester Elastomer for Corrosion Inhibitor Application

“…According to previous studies, the fluorosubstituted liquid crystals were characterized by good optical and chemical stability, low viscosity, high specific resistance, and low threshold voltage due to their high polarity. The number of fluorosubstituents also affected the orientation of molecules [ 24 , 25 ]. Therefore, in 4CFE with fluorosubstitutents, the direction of the ester bonds was also affected by the strong dipole moment, resulting in strong positive dielectric anisotropy [ 26 ].…”