Liquid Crystals

5Spontaneous Emergence of Chirality

Mohan SRINIVASARAO¹

¹ School of Materials Science and Engineering, School of Chemistry and Biochemistry, Center for Advanced Research on Optical Microscopy (CAROM), Georgia Institute of Technology, USA

5.1. Introduction

This chapter deals with the spontaneous emergence of chirality or chiral structures from materials that are achiral. We will primarily focus on the appearance of chiral structures in the context of the simplest of the liquid crystalline phases, the nematic phase, where the constituent molecules possess long-range orientational order. In doing so, we intend to take a broader approach, where our observations are contexualized, taking into account the historical developments dealing with “chirality”. We will begin with a discussion of chirality since the early 1800s, highlighting the many contributions of French scientists in the 19th century to molecular chirality. Since the manifestations of “chirality” have often been through optics, and, in particular, to the rotation of a light beam’s plane of polarization, it would seem not only appropriate but also required that we consider the history of these ideas in some detail.

Following these ideas, we shall discuss the appearance of chiral structures from achiral materials, in particular, from lyotropic nematic liquid crystals (LCs). A term that is often used to describe such appearances of chirality is “Chiral Symmetry Breaking”, a term that can be quite confusing, as well as, ...