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Dynamics of Colloids in Liquid Crystals

Date:  Thursday, January 10th, 2019

Time: 4:00pm

Location: 100 Willamette Hall

Speaker: Oleg D. Lavrentovich, Department of Physics, Advanced Materials and Liquid Crystal Institute, Kent State University

Abstract:

Dynamics of microparticles in fluids has fascinated scientists for centuries.  Phenomena such as electrokinetics of Janus spheres and swimming of microorganisms continue to inspire research and innovation.  The fluid in which the particles move is typically isotropic, such as water, and the dynamics is usually chaotic.  If one could learn how to control and streamline dynamics at microscale, it would open many technological opportunities.  This presentation describes how one can use an anisotropic fluid, namely, a nematic liquid crystal, to command the dynamics of living and inanimate microparticles. In nematics, molecules align along a preferred direction called the director.  A spatially-varying director field enables new mechanisms of transport and allows one to control many aspects of microscale dynamics. Three examples are considered: (i) liquid crystal-enabled electrokinetics; (ii) command of bacterial dynamics by a patterned director field; (iii) electrically powered 3D particle-like solitary waves. The main results are published in Nature 467, 947-950 (2010), Science 342, 1351-1354 (2013), Nature Comm. 5, 5033 (2014) and 9, 2912 (2018). Current work is supported by NSF grant DMREF DMS-1507637 and by the Office of Sciences, DOE, grant DE-SC0019105.

Host: John Toner

All attendees are invited to attend a colloquium reception in the Willamette Hall, Paul Olum atrium at 3:40pm.

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