Large Scale Simulations of Blue Phases of Cholesteric Liquid Crystals
- Event time: 1:00pm
- Event date: 15th December 2008
- Speaker: Oliver Henrich (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Blue Phases (BPs) are equilibrium phases in chiral nematic liquid crystals containing a lattice of disclinations. They are found in thermotropics close to the cholesteric-isotropic transition. While older experiments managed to stabilize BPs only in a very narrow temperature range of about 1 K, more recent ones have created BPs over a strikingly wide temperature range of 50 K. This opens up a completely new field of possible future applications. In order to study the technologically relevant flow and field response of BPs, large scale simulations are necessary as the lengthscale of the disclination network is in the region of visible light. Simulations of the domain growth of BPs in cholesteric and isotropic environments were performed as a kind of first approach to more complex situations. Furthermore, we looked into the response to electric fields and obtained a first phase diagram of BPs. Extended regions appeared where hexagonal BPs seem to be energetically favoured. In addition to this we suggest a structure for the amorphous BPIII in the form of a frustrated network. Close to the BP-isotropic transition a novel, presumably tetragonal blue phase was found, which will be shown in some detail.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..