GLASSY MESOPHASES AND FERROELECTRIC PROPERTIES OF CHIRAL LOW MOLAR-MASS LIQUID-CRYSTALS

The synthesis and physical characterization of a number of low molecul ar weight chiral liquid crystals is reported. Structurally the compoun ds are characterized by the presence of a chiral chain of the type -CO OR [R = -*CH(CH3)C6H13 or -*CH(CH3)COOC4H9] and, in some cases, the p resence of a hydroxy group in the ortho position of the adjacent aroma tic ring. Three of the compounds exhibit mesophases that pass into a g lassy state in which the chiral smectic C, smectic A, or chiral nemati c order is retained. The molecular modes in these phases have been cha racterized by dielectric measurements over eleven decades of frequency (10(-2)-10(9) Hz). Only one of the compounds shows chiral smectic C s ubphases. The influence of different structural characteristics (i.e., the central core, the chiral chain, and the lateral substituents) on the liquid-crystalline behavior, the glassy phase formation and the fe rroelectric properties, either as pure materials or in binary mixtures , is discussed.