This is a past event
Professor Helen Gleeson OBE from the University of Leeds' Soft Matter Physics Group
Liquid crystals allowed the development of the low-cost, lightweight, flat panel displays that underpinned the mobile revolution of our society about 20 years ago. Such devices make use of nematic liquid crystals, the simplest of a zoo of possible phases, which exhibits only long-range orientational (and no positional) order. Despite its simplicity, this genus of liquid crystals continues to offer surprises that are both intriguing in terms of their underlying physics and for the applications they could influence. This talk will describe two such systems. The responsive, shape-changing properties of nematic liquid crystal elastomers (LCEs) are the first category that the talk will address. LCEs are well-known and have inspired imaginative suggestions for applications including as artificial muscles, irises and sensors. However, the recent discovery of a family of nematic LCEs as the first synthetic molecular auxetics – with a negative Poisson’s ratio - has both broadened the possibilities and provided a puzzle in understanding the chemistry and physics underlying their auxetic behaviour. The second topic to be addressed is the recently-discovered polar nematic phase, which has values of spontaneous polarization that rival those of molecular crystals. These materials again offer wide-ranging and interesting applications, alongside challenges to understanding their behaviour. The talk will describe these two nematic systems, including the current understanding of the key parameters that control them that lead to material design rules. Finally, I will speculate on some ways in which they might contribute to global challenges.
- Speaker
- Professor Helen Gleeson OBE
- Venue
- Fraser Noble 2