Surface alignment of liquid crystals is central to most of their applications but remains rather poorly understood. Neutron refection has been used to study the build up of smectic layers at the interface at temperatures above the bulk transition. The interaction of a nematic with the surface is significantly different from a “hard wall” and we are now exploring roués to modify the director anchoring by the adsorption of dopants from the bulk nematic.
These offer the possibility of new materials with unusual optical or other properties that can be manipulated via the liquid crystal director. There are several scientific challenges including: colloidal stability, director anchoring at the particles’ surfaces and the energy cost of director distortion imposed by the particles. Small angle X-ray scattering is the principle methods used in these studies.
We have developed a new apparatus for confining thin films and adsorbed films between a flat solid surface and a flexible membrane. Using neutron and X-ray reflection methods, we aim to study the effects of nanoscale confinement to gain insight into the behaviour of polymer brushes in steric stabilization layers and liquid crystal formulations that have tribological applications.
The following people are involved in this research: