Cyclic Co-oligomeric Ferroelectric Liquid Crystals with Fast Switching Properties, Wide SmC^*Temperature Range and de Vries-type SmA^*-SmC^*Transition

Abstract

We have synthesized and characterized the first cyclic co-oligomeric ferroelectric liquid crystals (FLCs) based on cyclic siloxanes and found that the co-oligomer containing two different mesogenic units exhibits SmC* mesophase over a wide temperature range from 65 o C to 135 o C, much wider than those of the monomer counterparts and the cyclic homo-oligomers. The cyclic co-oligomeric liquid crystal readily filled the display cell and exhibited fast switching times in the range of 4 ms to 6 ms over the entire SmC* phase. Moreover, the practical absence of layer shrinkage, attributed to de Vries-type transition, shows an additional significant advanage for cyclic co-oligomeric FLCs in LCD applications.