Computer simulations of frustration in soft matter systems; from nematic shells to bolaamphiphiles

I will discuss some recent computer simulations of three different systems; nematic shells, sticky colloidal particles on surfaces and the bulk phases of liquid crystalline bolaamphiphiles. For nematic shells, a layer of liquid crystal is used to coat a microscopic particle. In this geometry, defects necessarily occur – the system is frustrated so that the director profile and local orientational ordering is not constant everywhere. We examine the interactions between the defects for a number of different types and shapes of particles and other cavities. I will also discuss sticky colloids on a flat surface. We will observe how different phases (or different shaped 'nets') can be templated onto the surface by minor modifications to the size and interactions of the sticky patches. Finally, we will examine the bulk phases of liquid crystalline bolaamphiphiles. These are unusual liquid crystals, with long side chains off a relatively rigid rod that form unusual columnar phases. They differ from conventional liquid crystal columnar phases in that the columns are aliphatic with aromatic walls, rather than aromatic columns with aliphatic walls. We examine how frustration in these systems can lead to novel phases, with unit cells significantly larger than single molecules.