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SUMMARY:Design of liquid crystal superstructures: geometry\, topology\, fl
 ow\, and mesophase - Ravnik\, M (University of Oxford/Ljubljana)
DTSTART:20130321T090000Z
DTEND:20130321T095000Z
UID:TALK44053@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Structuring of liquid crystalline fluids allows for various ex
 citing material mechanisms such as self-assembly [1]\, memory effects [2]\
 , entanglement [3]\, nonlinear electrophoresis [4]\, nonlinear rotary dyna
 mics [5]\, and nanoscopic surface shape changing [6]. Here\, we present st
 rategies for creating colloidal and bulk liquid crystal superstructures\, 
 in 2D and 3D\, using nematic\, twisted nematic\, and cholesteric blue phas
 es. Our work is based on the numerical minimization of the phenomenologica
 l Landau-de Gennes free energy and solving hybrid Lattice Boltzmann algori
 thm for Beris-Edwards nematodynamics model\, with full link to experiments
 . We show that 3D colloidal crystals can be assembled from elastic dipoles
  of spherical beads in nematic liquid crystals or via inherently inhomogen
 eous order profiles in cholesteric blue phases [7]. By using colloidal pla
 telets\, we show that crystalline [8] and quasi-crystalline symmetry can b
 e imprinted into the structures. Topological defects are manipulated into 
 structures of knots and links using various colloidal arrays [9]. Finally\
 , passive and active material flow is used to produce distinct backflow ge
 nerated complex nematic profiles in microfluidic channels. \n\n[1] P. Poul
 in\, H. Stark\, T. C. Lubensky\, D. A. Weitz\, Science 275\, 1770 (1997). 
 [2] T. Araki\, M. Buscaglia\, T. Bellini\, and H. Tanaka\, Nature Material
 s 10\, 303 (2011). [3] M. Ravnik\, et al\, Phys. Rev. Lett. 99\, 247801 (2
 007). [4] O. D. Lavrentovich\, I. Lazo and O. P. Pishnyak\, Nature 467\, 9
 47 (2010). [5] J. S. Lintuvuori\, K. Stratford\, M. E. Cates\, D. Marenduz
 zo\, Phys. Rev. Lett. 107\, 267802 (2012). [6] D. Vanzo\, M. Ricci\, R. Be
 rardi and C. Zannoni\, Soft Matter 8\, 11790 (2012). [7] M. Ravnik\, G. P.
  Alexander\, J. M. Yeomans\, and S. Zumer\, Proc. Natl. Acad. Sci. USA 108
 \, 5188 (2011). [8] J. Dontabhaktuni\, M. Ravnik and S. Zumer\, Soft Matte
 r 8\, 1657 (2012). [9] U. Tkalec\, M. Ravnik\, S. Copar\, S. Zumer and I. 
 Musevic\, Science 333\, 62 (2011).\n
LOCATION:Seminar Room 1\, Newton Institute
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