Emergence of polar order and tilt in terephthalate based bent-core liquid crystals

Abstract

A new bent-core liquid crystalline material consisting of a 4-cyanoresorcinol unit with two terephthalate based rod-like wings and terminated by two short alkyl chains was synthesized. Its liquid crystalline (LC) self-assembly and the development of polar order in the LC phases were investigated. The polar order is characterised using second harmonic generation and dielectric spectroscopy techniques in addition to XRD and DSC characterisations of the mesophase structure and investigation of freely suspended films. We demonstrate the growth of ferroelectric domains in the paraelectric SmA phase (SmAP_R), which adopt antipolar correlations (SmAP_AR) and eventually condense into a weakly tilted antiferroelectric smectic phase (SmC_aP_A).