SYNTHESIS AND CHARACTERIZATION OF NEW SERIES OF FERROELECTRIC LIQUID-CRYSTALS CONTAINING OLIGOOXYETHYLENE SPACERS

Four series of ferroelectric liquid crystals containing oligooxyethyle ne spacers have been synthesized. These obtained liquid crystal compou nds were characterized by NMR, differential scanning calorimetry (DSC) and optical polarized microscopy (POM). The properties of the liquid crystalline phase were investigated as a function of spacer units, num bers of core aromatic rings, and different terminal asymmetric moietie s. It was found that (i) the phase transition temperature decreased wi th the increasing oligooxyethylene spacer unit, (ii) the liquid crysta lline phases were enhanced in three phenyl ring system than in two phe nyl ring system, and (iii) ferroelectric liquid crystals containing di fferent terminal asymmetric moieties exhibited novel mesophase phenome na. A twist grain boundary phase (TGB(A) phase) was observed in some c ompounds of this study. Furthermore, a wide temperature chiral smectic C range including room temperature was achieved.