Antiferroelectric liquid crystal from a banana-shaped achiral molecule

A new banana-shaped achiral compound, 1,3-phenylene bis[4-(3-fluoro-4-n-oct yloxyphenyliminomethyl) benzoate] ( PBFOB) was synthesized and its antiferr oelectric liquid crystallinity determined. The PBFOB was characterized by d ifferential scanning calorimetry, X-ray diffractometry in the small and wid e angle regions, and polarizing optical microscopy; its polarization and an tiferroelectric properties were also investigated. The presence of a latera l fluoro-substituent in the banana-shaped achiral molecules containing a Sc hiff's base mesogen induced a decrease in melting temperature and formation of the switchable smectic B-2 phase in the melt. The spontaneous polarizat ion for PBFOB was about 250 nC cm(-2) and the polarization of this phase sw itched on the reversal of an applied electric field.