Dielectric Study of Liquid Crystals with Large Electroclinic Effect

Here we report results of the study of tilt angle and birefringence of some "high-electroclinic" materials having similar molecular structure with two and three siloxane spacers. The structure of these LC materials were studied by dielectric spectroscopy, birefringence and tilt angle measurements. Three of the four studied materials with a siloxane fragment are the deVries materials, but the siloxane-free sample is conventional SmA phase and is thus different. Possible models for the molecular structures of deVries SmA∗ phases are discussed.