Glassy mesophases and ferroelectric properties of chiral low molar mass liquid crystals

The synthesis and physical characterization of a number of low molecular weight chiral liquid crystals is reported. Structurally the compounds are characterized by the presence of a chiral chain of the type -COOR* [R = -*CH(CH3)C6H13 or -*CH(CH3)COOC4H9] and, in some cases, the presence of a hydroxy group in the ortho position of the adjacent aromatic ring. Three of the compounds exhibit mesophases that pass into a glassy state in which the chiral smectic C, smectic A, or chiral nematic order is retained. The molecular modes in these phases have been characterized by dielectric measurements over eleven decades of frequency (10(-2)-10(9) Hz). Only one of the compounds shows chiral smectic C subphases. 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 ferroelectric properties, either as pure materials or in binary mixtures, is discussed.