Chapter 6
Light-Driven Chiral Molecular Switches or Motors in Liquid Crystal Media
6.1 Introduction
Thorough understanding and/or mimicking nature's art of expressing and augmenting chirality from microscopic to mesoscopic levels remains elusive. However, the ubiquitous bio-molecular self-assembly into helical structures such as the double helix of DNA, α-helix of peptides, and the elegant colors of butterfly wings, bird feathers, and beetle exoskeletons [1–4] has inspired chemists to develop novel materials not only to reveal the structure–property correlation but also to explore their usage in diverse technological applications. The foremost objective of such studies has been the design and synthesis of chiral molecular systems capable of yielding complex large scale helical structure originating from the manifestation of chirality in the constituent molecules through non-covalent supramolecular interactions. Among the self-organized supramolecular systems, liquid crystals (LCs) represent a promising class of materials which might exhibit stable supramolecular helical organizations if the mesogens are chiral. The fascinating helical superstructure of chiral nematic LCs, i.e., cholesteric LCs (CLCs), undoubtedly is a striking example of such self-organization owing to its unique property of selective reflection of light and its consequent potential applications. However, large scale production ...
