Electro-optical investigations and effect of asymmetry in bent-core liquid crystals

Abstract

We report the synthesis and mesomorphic properties of a homologous series (10a–10g) of bent-core molecules constructed through covalent linkage of structurally non-symmetrical rod-like mesogens connected with a 1, 3-phenylene unit. The study of homologous series underlines the importance of length and nature of terminal chains. The homologues of shorter chains show a typical non-switchable rectangular columnar B1 phase, while the switchable lamellar (B2) phase is induced on moving to higher homologues. X-ray diffraction patterns indicate the presence of B1 and B2 mesophases. Polarised optical microscopy investigations under electric field in the B2 phases revealed the existence of anticlinic antiferroelectric texture. The measured spontaneous polarisation value in one of the compounds is 936 nC cm−2, a high polarisation value in bent-core liquid crystals.