SYNTHESIS AND CHARACTERIZATION OF NEW FERROELECTRIC LIQUID-CRYSTALS CONTAINING A OXYBIPHENYL-4'-CARBONYLOXY)-2'-NAPHTHYL]PROPIONATE MESOGENIC GROUP AND OLIGO(OXYETHYLENE) SPACERS

Three series of ferroelectric liquid crystals containing a (6-(4-hydro xybiphenyl-4'-carbonyloxy)-2'-naphthyl) propionate mesogenic group and oligo(oxyethylene) spacers were synthesized. These obtained liquid cr ystal compounds were characterized by NMR, differential scanning calor imetry (DSC), optical polarized microscopy (POM), and X-ray powder dif fraction measurements. Some of these materials containing four phenyl rings of ester cores (i.e. -Ph-Ph-COO-naph-) and chiral heptyl tail ex hibited a rich mesomorphic behaviour, a blue phase (BP), a cholesteric phase (Ch), a smectic A (S-A), a twist grain boundary A (TGB(A)), and a chiral smectic C (S-C) phase. Another series containing four pheny l rings of ester cores and chiral butyl and pentyl chain tails reveale d only a S-A phase and a S-C phase. Moreover, a crystal E phase was o bserved in the short spacer chain (n=0 or 1) homologues of three serie s of compounds. Also, the mesomorphism properties were discussed as a function of spacer units, numbers of aromatic rings of core, and diffe rent terminal asymmetric moieties.