| Complex assemblies of particles in achiral and chiral nematic phases will be described. Particular stress will be given on our recent modeling of such structures. Results will be contrasted with the latest experimental studies. Our approaches are based on phenomenological description and topological theory. In solvents where nematic order is present an effective anisotropic long range inter-particle coupling appears. It leads to numerous organizations of colloidal particles not present in simple liquids. Particularly interesting are situations where topological constrain results in sharing of a disclination line by neighboring particles that leads to a string-like coupling [1-3]. Colloidal dimers, trimers, chains, lattices, braids, and hierarchal structures can be realized either via disclination loops with singular or nonsingular cores. Effects of chiral distortions and confinement will be illustrated by 2 dimensional structures in twisted cells and by 3D assemblies in blue phases. We expect that nematic colloids will open new ways to the assembling of complex structures needed for metamaterials.
References:
(1) M. Ravnik, M. Škarabot, S. Žumer, U. Tkalec, I. Poberaj, D. Babič, N. Osterman, and I. Muševič, Entangled Nematic Colloidal Dimers and Wires, Phys. Rev. Lett 99, 247801 (2007), also in Virt. J. Nanoscale Sci. & Techn 16, 26 (2007)
(2) M. Škarabot, M. Ravnik, S. Žumer, U. Tkalec, I. Poberaj, D. Babič, I. Muševič, Hierarchical self-assembly of nematic colloidal superstructures, Phys. Rev. E 77, 061706 (2008), also in Virt. J. Nanoscale Sci. & Technol 17, 25 (2008)
(3) M. Ravnik and S. Žumer, Nematic colloids entangled by topological defects, Soft Matter (2009) 5, 269
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