A Pictorial Approach to Helical Macrostructures in Smectic Liquid Crystals

Abstract

Physical theories concerning the structures and properties of chiral smectic liquid crystals abound, however, very few are of practical use in the design and subsequent synthesis of materials. The development of macroscopic theories, although very useful in the explanation of physical phenomena, are not readily transferable to the microscopic state. Thus, the design of materials depends more on a qualitative approach supported by property-structure correlations than it does on quantitative deliberation. However, viewing the formation and stabilisation of mesophase structures from the microscopic molecular aspect can lead to some very interesting perspectives. In this article, crude or gross molecular shapes are used to investigate local packing arrangements of chiral molecules in layered mesophases. The formation of helical macrostructures is readily described using this form of modelling, and in turn the formation of antiferroelectric and twist grain boundary phases can be rationalised in terms of property-structure correlations.

Key Words:

• Chirality
• helicity
• ferroelectric
• antiferroelectric liquid crystals