Glass forming banana-shaped compounds: vitrified liquid crystal states.

The synthesis and physical properties, in particular electro-optic switching behavior, of 3-chloro-biphenyl-3',4-bis[4-[4-(3,7-dimethyloctyloxy)-phenyliminomethyl]] benzoate are reported. The compound exhibits an antiferroelectric tilted smectic liquid crystalline phase (Sm-CP) in a broad temperature range. Below 20 degrees C the sample goes over to a glassy state and no crystallization appears down to -50 degrees C. It is observed that below the glass transition temperature both achiral and chiral structures of the Sm-CP phase can be frozen. Each of them can have three polarization states (two ferroelectric and one antiferroelectric), thus giving six different vitrified textures. This enables atomic force microscopy studies of the different liquid crystalline states and suggests possibilities for electro-optical storage devices.