Electro-Optic Properties of an Unusual Guest-Host Liquid Crystal Mixture: A Mauve Anthraquinone Dye in a Ferroelectric Organosiloxane

Abstract

We examine here the electro-optic properties of an unusual guest-host liquid crystal mixture of a high contrast anthraquinone dye and a new ferroelectric organosiloxane liquid crystal. From measurements of the transition temperatures, tilt angles, spontaneous polarisations and rotational viscosities, we show that dye concentrations as high as 4% w/w have negligible effect upon the host properties. Furthermore, we show that the mixture, with a constant tilt angle of 36° across its smectic-C* phase range from 50°C down to 10°C, high absorbance and good alignment, produces contrast ratios in the V-V scattering mode of 50:1 or higher, with optical response times of 120 μs or less at 20°C. We argue that the technological implications of mixtures of this type are important, due to their being composed of only two components and having properties surpassing that of commercial optimised mixtures.

Key Words:

• Ferroelectric
• guest-host
• organosiloxane
• anthraquinone