Ferroelectric and antiferroelectric banana phases'' of new fluorinated five-ring bent-core mesogens

Two homologous achiral five-ring mesogens with lateral fluorine substituents on the core and on the outer rings are presented. Both compounds exhibit two B-5 phases and the B-2 phase. The high-temperature B-5 phases possess an antiferroelectric ground state. The low-temperature B5 phase was found to be ferroelectric, which is indicated by the bistable switching. The assignment and characterization of the mesophases is based on XRD measurements, H-1-, F-19-, C-13-NMR and electro-optical measurements.