287692 Elastic Induced Colloidal Interactions in Liquid Crystals

Monday, October 29, 2012
Hall B (Convention Center )
Marcello Cavallaro Jr.1, Mohamed Amine Gharbi2, Daniel Beller3, Lu Yao1, Randall Kamien3, Shu Yang3 and Kathleen J. Stebe4, (1)Chemical & Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, (2)Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, (3)University of Pennsylvania, (4)Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA

In this work, we exploit well defined boundary conditions to control the formation of defects in nematic liquid crystal (NLC) 5CB. When supported between micropost arrays, disclination lines form and bear the signature of the micropost shape owing to the elasticity of the medium. The existence of these disclination lines can be tuned due to the thermotropic nature of the material simply by varying temperature thereby providing an element of control not present in typical isotropic fluids. When colloids are introduced to a nematic liquid crystal, elastic distortions arise that have an associated Frank free energy cost. This excess energy is reduced by interacting with the micropost induced disclination lines and subsequent colloid-micropost attractions arise. We consider both isotropic particles (spheres) and more complex anisotropic particles. Further, we observe these effects 5CB-air interfaces as well as in bulk 5CB. This work is experimental and supplemented with analysis to support the observed behavior.

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See more of this Session: Interfacial Phenomena (Area 1c) Poster Session
See more of this Group/Topical: Engineering Sciences and Fundamentals