Chapter 8: Electrical Color Tuning in Polymer-stabilized Cholesteric Liquid Crystals

Cholesteric liquid crystals consist of chiral rod-like molecules which self-assemble into a helical structure. The molecules twist periodically along an axis which is orthogonal to the long molecular axis. For cholesteric liquid crystals with a helical pitch comparable to the wavelength of visible light, they Bragg reflect light. In this chapter we discuss polymer-stabilized cholesteric liquid crystals where polymer networks are dispersed in the liquid crystals to control the electro-optical properties of the liquid crystals. The reflection of the polymer-stabilized cholesteric liquid crystals can be tuned by applying electric voltages. The materials are of great practical importance and can be used in many applications such as reflective displays, writing tablets, tuneable color filters and tuneable mirror-less lasers.