Investigation of the electrothermo-optical effect of a smectic LCP-nematic LC-chiral dopant ternary composite system based on S_A ↔ N^* phase transition

A sharp change in transmittance from a transparent state to a light scattering one within a tiny temperature range is induced accompanied with the heat-induced phase transition from a smectic-A (S_A) phase to a chiral nematic (N^*) one in a side-chain smectic-A liquid crystalline polymer (S_ALCP)-low-molecular-weight nematic liquid crystal (NLC)-chiral dopant ternary composite system with a homeotropic boundary condition. By adjusting the polymer ratio, an induced N^* phase exhibiting strong light scattering over a wide temperature region has been obtained. The resulting scattering texture retained in the S_A phase due to fast cooling from the N^* phase can be rather stable and can be easily erased by cooling slowly from the N^* phase to the S_A phase after the scattering texture being heated into the N^* phase again or by application of an alternating current electric field on the scattering texture directly. Based on these characteristics, it is very possible that this composite system will be used as a novel thermal addressed liquid crystal display material with respect to a fast response, a high contrast, and a durable memory effect.