Soft Condensed Matter

Mechanism of nematic anchoring

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.

New nematic materials based on nanoparticle in nematic suspensions

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.

The influence of confinement on liquid crystal phases

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.

Neutron reflection data from a liquid crystal - solid interface. Data collected from the neutron reflection experiment is complex, containing several components which require sophisticated data analysis to separate.

Latest publications

Data taken at the European Synchrotron Radiation Facility from a suspension of platelike particles of clay in nematic 5CB with magnetic alignment. The clay particles form a stack to give the pseudo-Bragg peaks and the director of the 5CB is indicated by the diffuse peak.