Paraelectric–antiferroelectric transitions in the bent-core liquid-crystalline materials

Abstract

Ferroelectric liquid crystalline phases formed by achiral bent-core mesogens have been known for about seven years. However, only few materials have been found to exhibit both conventional nematic/smectic mesophases and “banana” phases, where steric packing of bent mesogens results in ferroelectric properties. In this paper we report some studies of such compounds showing transitions between paraelectric smectic A, smectic C and antiferroelectric smectic CP phases. Structure characterization as well as studies of ordering in mesophases have been performed with the help of a variety of experimental techniques including X-ray diffraction, NMR and dielectric spectroscopy as well as electrooptical measurements.