PhD project: Computational Physics of Liquid Crystal Composites

Project description

Liquid crystals are a fascinating example of soft materials. Like liquids, they flow and may be poured from one vessel to another. Like solids, they possess long range orientational order. Common examples are nematic liquid crystals (in which molecules align along a preferred axis) and cholesterics (in which this ordering axis acquires a spatial twist). Both are used in optical displays. Edinburgh physicists have developed lattice Boltzmann algorithms for large-scale numerical simulations of the hydrodynamics of liquid crystals, and used this to study permeation flows and the exotic 'blue phase' [1]. We have also studied binary mixtures of simple fluids, and colloids (including magnetic colloids) in single and binary solvents; this has led to the prediction by simulation of a completely new material [2] which was then found experimentally by our collaborators [3]. In progressing this leading edge work to the next stage, you will exploit our existing codes as well as develop new ones, aiming to investigate a new class of soft materials in which colloids are dispersed in liquid crystals [4,5], and/or binary fluid mixtures are formed in which one of the two fluids is liquid crystalline. Such materials should allow new levels of control over properties and unusual responses to fields and flow. There is so far only a small experimental literature on these composite systems [5] and very little simulation work. The field is open for new discoveries: our in-house experimental collaborators [3,5] await our findings with interest!

[1] Ordering Dynamics of Blue Phases Entails Kinetic Stabilization of Amorphous Networks. O. Henrich, K. Stratford, D. Marenduzzo and M. E. Cates, Proc. Nat. Acad. Sci. USA 107, 13212 (2010); Structure of Blue Phase III of Cholesteric Liquid Crystals, O. Henrich, K. Stratford, M. E. Cates and D. Marenduzzo, Physical Review Letters 106, 107801 (2011)

[2] Colloidal Jamming at Interfaces: A Route to Fluid-Bicontinuous Gels, K. Straftord, R. Adhikari, I. Pagonabarraga, J.-C. Desplat and M. E. Cates, Science 309, 2198-2201 (2005); E. Kim et al, Langmuir 24, 6549-6556 (2008)

[3] Bicontinuous Emulsions Stabilized by Colloidal Particles, E M Herzig, K A White, A B Schofield, W C K Poon and P S Clegg, Nature Materials 6,966-971 (2007)

[4] Colloids in Cholesterics: Size-Dependent Defects and Non-Stokesian Microrheology, J. S. Lintuvuori, K. Stratford, M. E. Cates and D. Marenduzzo, Physical Review Letters 105, 178302 (2010)

[5] A Self-Quenched Defect Glass in a Colloid-Nematic Liquid Crystal Composite, T. A. Wood, J. S. Lintuvuori, A. B. Schofield, D. Marenduzzo and W. C. K. Poon, Science 333, 79 (2011)

Project supervisors

  • (School of Physics & Astronomy, University of Edinburgh)
  • Dr Kevin Stratford (EPCC, University of Edinburgh)

The project supervisors welcome informal enquiries about this project.

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