Research interests
Professor Helen Gleeson
1. Resonant X-ray Scattering
We carry out experiments on antiferroelectric, ferrielectric and ferroelectric liquid crystal films and devices. Resonant scattering techniques probe the substructure of phases. We have deduced the biaxial nature of the 3-layer structures as well as details of the biaxial structure of the 4-layer phase. We have also used Kossel Diagrams to deduce structures and phases of structures in the liquid crystal blue phases and other chiral systems.
2. Time Resolved X-ray Scattering
Time Resolved X-ray Scattering is undertaken on smectic liquid crystal devices. We were the first in the world to carry out time resolved X-ray studies of liquid crystal devices on a microsecond time scale and have studied electric field effects in smectic-A, smectic-C, ferroelectric, ferrielectric and antiferroelectric liquid crystals in device configurations.
3. Laser manipulation
Laser manipulation is carried out on particles in achiral and chiral liquid crystal media, and we also study the transfer of optical angular momentum to liquid crystalline droplets. Most recently, this includes the remarkable discovery of rotation of chiral droplets when illuminated with linearly polarized light.
4. Photosensitive systems
We have carried out extensive studies of photochromic liquid crystals including optically induced changes in structure and order in functional materials.
5. Sensors
We have collaborative projects with industrial partners making use of liquid crystal systems in novel sensors for biological hazards, and as time-temperature sensors for fragile produce.