Theories of defect structures found in smectic-A liquid crystals

This thesis consists of four studies describing the physical and mathematical modelling of some defect structures found within smectic-A liquid crystalline phases. The first study extends the simple static chevron theories to include variations of both nematic and smectic elastic constants. In the second study the dynamics of chevron formation are investigated. The dynamics are governed by smectic-A hydrodynamics and can be separated into two processes known as mass flow and permeation. Chevron evolution as a result of each process is presented. The symmetry of the chevron structure leads to the existence of two stable polarities. The boundaries between domains of opposing polarities are known more commonly as zig-zag defects. Investigations into the boundary structure is the subject of the third study. The chevron structure is an example of a small angle grain boundary located in the centre of the cell. The structure of large angle tilt grain boundaries are expected to be composed of a different interface structure. This possibility is considered in the fourth study. (author)