Effect of enantiomeric excess on surface structures and phase sequences in free-standing liquid-crystal films

Abstract

We present differential optical reflectivity and null transmission ellipsometry data from several mixtures of MHPBC enantiomers. From this data, we have determined the chiral smectic phase sequence as a function of enantiomeric excess. The data suggest a change in the structure of the smectic-C(alpha)* phase and the surface tilt state as the enantiomeric excess is reduced. The results also show that the intermediate phases, smectic C(FI2)*, smectic C(FI1)*, and smectic C(alpha)*, disappear sequentially on reducing the net chirality.