Experimental investigations of one liquid-crystal compound exhibiting the no-layer-shrinkage effect near the Sm-A-Sm-C* transition

The nature of the smectic-A-smectic-C phase transition of one liquid-crystal compound showing almost no layer-shrinkage effect through the transition was investigated by using three experimental probes. X-ray diffraction and optical studies showed that the compound demonstrates a crossover behavior of different molecular packing arrangements within the bulk Sm-A phase window. It was found using calorimetry that there is a significant critical anomaly near the Sm-A-Sm-C^* transition, although it is of weakly first order. It was also observed using electro-optical investigations that the de Vries compound has a first-order Sm-A-Sm-C^* transition.