Low molar mass organosiloxane liquid crystalline dyes for dye guest host ferroelectric display devices

In low molar mass organosiloxane liquid-crystal materials the siloxane moie ties micro-separate and aggregate in planes that could be regarded as an ef fective or virtual two-dimensional polymer backbone. We show that if a silo xane moiety is attached to a dichroic dye molecule, the micro-segregation o f the siloxane moieties makes it possible to include a high concentration o f the guest dye (more than 50%) in a host organosiloxane solution. This eff ect, combined with the temperature independent tilt angles achievable with ferroelectric organosiloxane liquid crystals, provide an ideal material for high-contrast surface-stabilised ferroelectric display devices. We present dyed ferroelectric materials with a temperature independent tilt angle gre ater than 42 degrees, a wide (room temperature to over 100 degrees C) mesom orphic temperature range and a response time shorter than 500 mu s in the d ye guest host mode.