November 30, 2012, 3:10 pm to 4:00 pm

"Colloidal Particles in Liquid Crystals: Statics and Dynamics," by Oleg D. Lavrentovich P'08 (Physics Colloquium Series)

Dr. Lavrentovich is with the Liquid Crystal Institute and Chemical Physics Interdisciplinary Program at Kent State University.

Abstract: Colloids and liquid crystals are two important classes of soft matter, usually explored independently of each other. The most studied colloids represent a dispersion of solid or liquid particles in an isotropic fluid such as water. The simplest liquid crystal, a nematic, is a fluid with long-range orientational order of molecules. This presentation reviews recent studies of liquid crystal colloids, i.e., dispersions of particles in a liquid crystal. The long-range orientational order imparts anisotropic elastic interactions of colloidal particles [1]. Elastic repulsion from the bounding walls opposes gravity and keeps the particles levitating in the liquid crystal bulk [2]. The levitating particles can be set into motion by applying an electric field. Liquid crystals enable a new mechanism of electrophoresis, in which the particle's velocity is proportional to the square of the electric field. The latter is dramatically different from the classic electrophoresis with a linear relationship. The nonlinear feature allows one to use an AC driving to maintain steady flows, to move particles that are electrically neutral and to design three dimensional trajectories of their motion.

Reception to follow.

Location: Franklin Miller, Jr. Lecture Hall (Hayes 109)

Sponsor: Department of Physics

Contact: Connie M. Miller

Email: millercm@kenyon.edu

Phone: (740) 427-5069

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