Colloidal liquid crystals, plastic crystals and glasses of rod-like silica particles
- Event time: 1:00pm
- Event date: 2nd March 2015
- Speaker: Thijs Besseling (Utrecht University)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Rod-like colloids can serve as a model system to study a wide variety of phenomena such as liquid crystalline phase behavior, nucleation and growth mechanisms and anisotropic diffusion. We studied a system of fluorescent rod-like silica colloids, using a combination of 3D confocal microscopy and a new single particle tracking technique [1,2]. This allowed us to study the particles in-situ and on the particle level. By changing the screening length of the particles by a full order of magnitude, we tuned the interactions from hard to long-range repulsive (or soft). At small screening lengths and high concentrations we found that these particles form equilibrium nematic, smectic-B and orientationally ordered crystals, which we analyzed in 3D on a single-particle level. For larger screening lengths, we found that particles formed a plastic crystal (or rotator phase) already at very low concentration and, surprisingly, a ‘plastic glass’ at higher concentration . Both the plastic crystal and the plastic glass could be switched to a fully ordered crystal upon application of an electric field.
 A. Kuijk, A. van Blaaderen and A. Imhof. JACS 133, 2346 (2011)
 T. H. Besseling, M. Hermes, A. Kuijk, B. de Nijs, T. Deng, M. Dijkstra, A. Imhof, and A. van Blaaderen, J. Phys. Condens. Matter, accepted, arXiv:1406.4985v1 (2014)
 B. Liu, T.H. Besseling, M. Hermes, A.F. Demirörs, A. Imhof, and A. van Blaaderen, Nat. Commun. 5, 3092 (2014)
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..