Dresden 2014 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 36: Colloids and Complex Liquids II
CPP 36.5: Talk
Wednesday, April 2, 2014, 16:00–16:15, ZEU 114
Effects of flow on topological defects in a nematic liquid crystal near a colloid — •Tillmann Stieger1, Martin Schoen1,2, and Marco G. Mazza3 — 1Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany — 2North Carolina State University, 911 Partners Way, Raleigh, North Carolina 27695, USA — 3Max Planck Institut für Dynamik und Selbstorganisation, Am Faßberg 17, 37077 Göttingen, Germany
Microfluidic applications are becoming an extremely important tool to manipulate fluids, droplets and materials at small scales. Anisotropic liquids are a promising novel approach to such applications. However, a clear understanding of the modifications induced by flow when a colloid is immersed in a liquid crystal is still missing. Our molecular dynamics simulations show that flow has in fact a significant impact on defect structures around a colloidal particle. We show that flow distorts Boojum defects into an asymmetrically larger downstream lobe, and that Saturn ring defects are convected downstream along the flow direction, which is in agreement with experimental observations [1]. Additionally, for a Janus colloid with both parallel and perpendicular patches, exhibiting a Boojum defect and a Saturn ring defect, we find that the Boojum defect facing the upstream direction is destroyed and the Saturn ring is convected downstream.
[1] S. Khullar, C. Zhou, and J. J. Feng, Phys. Rev. Lett. 99, 237802 (2007).