Instabilities in smectic A liquid crystals

• Main Author: Miscandlon, Jill
• Published: University of Strathclyde 2012
• Subjects: 510
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576400

In this thesis, the behaviour and stability of smectic A and smectic C liquid crystals are considered under the application of external influences. The behaviour of smectic A liquid crystals under oscillatory shear will be modelled using dynamic continuum theory recently developed by Stewart (2007). The dynamic continuum theory developed by Leslie, Stewart and Nakagawa (1991) is used to model smectic C liquid crystals under the effects of oscillatory shear flow and electric fields. Equilibrium solutions are presented for smectic A liquid crystals in which the director n and unit normal a are not forced to coincide. The stability of these solutions is then investigated and conclusions are drawn on the effect of changing geometries. The two experimental geometries studied consist of planar homeotropically aligned smectic layers and bookshelf aligned layers. The case in which n and a are allowed to decouple is then considered for the bookshelf aligned layers, with full nonlinear solutions presented along with a linear stability analysis. Bookshelf aligned smectic A will be considered subject to an oscillatory shear in both the finite and semi-infinite domains. Planar aligned smectic C will also be considered subject to an oscillatory shear in the cases when the director is aligned parallel and perpendicular to the oscillation. Smectic C* liquid crystals are analysed under the influence of an electric field. This is based on work already in the literature which is then extended to include elastic effects. Finally, the effect of surface anchoring on the behaviour of lipid bilayers is briefly discussed.