Some heterogeneous structures in liquid crystals made of bent core molecules and their mixtures with rod-like molecules

Abstract

We present a broad overview of the heterogeneous structures observed in liquid crystals (LC) made of bent core (BC) molecules. In particular, nematic LCs are known to have clusters with 100s of BC molecules, and many compounds with moderate layer polarisation (P) exhibit stripes in the layers with divP distortion. Such stripes have been found in SmAPmod phase made of nontilted molecules, the B7 phase with tilted molecules and bilayer SmCgmod phase in which the BC molecules tilt with general orientation. We argue that all these phenomena arise from the conformational variety of the BC molecules, about 10–20% of which are in an excited state with a larger opening angle compared to the majority of ground state molecules with a smaller opening angle. We outline our theoretical results on these systems. We also analyse the structures found in the modulated LC phases induced in some binary mixtures of compounds made of BC and rod-like molecules. We end with some personal recollections about Sadashiva.