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1. Fluorescence Confocal Polarizing Microscopy of Three-Dimensional Director Configurations in Liquid Crystals Oleg D. Lavrentovich, Kent State University, DMR 0504516 Top plate We use our 3D imaging technique of Fluorescence Confocal Polarizing Microscopy (FCPM) to study dynamics of colloidal particles dispersed in a liquid crystal. The topic is complex as the hydrodynamics of liquid crystals is non-Newtonian and anisotropic; adding colloids brings even higher level of complexity. The particles distort the liquid crystal creating a dipole-like field and leading to the levitation effect: elastic repulsion from both top and bottom plates keeps the colloids in the middle of the cell. By applying the electric field across the cell, the particles are moved to one of the substrates, depending on the direction of their elastic dipoles (top figure). By switching the field on and off, the particles with opposite dipoles are moved into opposite directions (bottom figure). This unique system with bidirectional motion allows us to study non-equilibrium processes and develop new microfluidic devices. px<0 px>0 Bottom plate Colloidal particles with opposite dipolar orientation are moved in opposite directions by alternating electric field O.P. Pishnyak et al., Phys. Rev. Lett., accepted (August 2007)

2. Fluorescence Confocal Polarizing Microscopy of Three-Dimensional Director Configurations in Liquid Crystals Oleg D. Lavrentovich, Kent State University, DMR 0504516 Broader impact 3D imaging by FCPM is a powerful and practically unique technique that allows one to decipher the properties of liquid crystal colloids with complex patterns of director distortions. FCPM helps us to develop practical devices such as real-time liquid crystal biosensors and fast switching displays. The research results were incorporated in graduate courses and numerous tutorials given by the PI both at the graduate and undergraduate levels, including an International Liquid Crystal Conference -2006. We performed FCPM studies in collaboration with a number of colleagues in the US and worldwide, at University of Illinois at Urbana-Champaign and Raman Research Institute, India, at the Institute of Physics in Ukraine and Harvard University. Participating graduate students and postdocs gained knowledge in materials sciences, physics and optics and in the development of practical devices. We take advantage of the existing NSF REU program at KSU and attract undergraduate student to do research close to this project. Our polarizing-microscopy microscopic textures of liquid crystals have been used by Prof. Bethanie J. Hills Stadler, University of Minnesota, as a demonstration of nanostructured materials at an open house for Lego League teams (4-12 grade) with about 450 students from 70 schools in attendance;  30% girls, 12% minorities.  3 of the schools were rural, 12 were urban, the rest suburban. We published 4 articles in Phys. Rev. Lett. and 5 more in other journals.