CHIRALITY, SURFACE ANCHORING, AND THE CHOLESTERIC-SMECTIC-A PHASE-TRANSITION

Magnetic Freedericksz transition measurements were performed on sample s of chiral and racemic mixtures in the cholesteric/nematic phase. We found that the quantity Phi, which is defined as the threshold field H -th times the cell thickness, is larger for the chiral than for the ra cemic mixtures. This result is inconsistent with chiral contributions to the anchoring strength potential. Instead, the data support a model by Lubensky wherein the transition temperature to the smectic A phase is suppressed in a chiral liquid crystal.