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

Abstract

Two homologous achiral five-ring mesogens with lateral fluorine substituents on the core and on the outer rings are presented. Both compounds exhibit two B5 phases and the B2 phase. The high-temperature B5 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, 1H-, 19F-, 13C-NMR and electro-optical measurements.