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

Four series of ferroelectric liquid crystals containing oligooxyethylene spacers have been synthesized. These obtained liquid crystal compounds 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, numbers of core aromatic rings, and different terminal asymmetric moieties. It was found that (i) the phase transition temperature decreased with the increasing oligooxyethylene spacer unit, (ii) the liquid crystalline phases were enhanced in three phenyl ring system than in two phenyl ring system, and (iii) ferroelectric liquid crystals containing different terminal asymmetric moieties exhibited novel mesophase phenomena. A twist grain boundary phase (TGB(A) phase) was observed in some compounds of this study. Furthermore, a wide temperature chiral smectic C range including room temperature was achieved.