University of Minnesota
School of Physics & Astronomy

Academic Calendar

Thursday, November 9th 2017
09:00 am:
Thesis Defense in Tate 201-20
Speaker: Chris Conklin, University of Minnesota
Subject: Electrokinetic Phenomena and Singularity-Driven Flows in Nematic Liquid Crystals
This is the public portion of Mr. Conklin's thesis defense. His advisor is Jorge Vinals.

Electrokinetic phenomena, including electrophoresis and electroosmosis, provide a significant tool for engineering the transport of fluids and particles at microscopic scales. This thesis describes additional mechanisms for generating electrokinetic flow by using a nematic liquid crystal electrolyte. Under an applied electric field the anisotropic properties of the liquid crystal lead to separation of ionic impurities present in the fluid, which couple with the applied field to produce electrostatic forces that drive fluid and particle motion. This force is quadratic in the electric field, implying that systematic flow occurs even in the presence of an oscillating field. This thesis presents numerical and analytical investigations of this electrokinetic mechanism. We show that the charge density and fluid velocity of a system depends strongly on the topology of the liquid crystal orientation, and we present results for several distinct configurations, including periodic distortions, isolated disclinations, and particle suspensions. We also show that liquid crystal electrokinetic systems can be designed to mimic the behaviors of active nematics -- collections of particles which can self-propel along a particular direction.

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