Liquid Crystals in Complex Fluid Systems

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9974388MeyerThis project addresses the topics of liquid crystal gel systems, and symmetry and textures in thin films of smectic liquid crystals. In the area of liquid crystal gels, experiments will be carried out to explore the coupling of the gel network to the nematic liquid crystal, which imparts unique properties to this system. Electro-optical microscopy experiments will be performed, including studies of the symmetry of the sample response, and the formation of domain walls, as a function of applied voltage and sample thickness. Macroscopic and microscopic mechanical experiments will be performed to observe directly the gel-nematic coupling, and gel microspheres will be explored as a useful experimental geometry. Thin smectic films will be studied, comparing free standing films with polar films on the surface of a liquid, with special attention to the changes in texture resulting from the change in symmetry of the film. Computations will be carried out to try to account for the observed textures, in terms of models for the free energy of these systems. Experimental methods include polarized light video microscopy, and manipulation of the sample texture with electric fields and optical tweezers, which are highly focused laser beams.Fundamental studies of the structural and molecular properties of electro-optic effects in nematic gels and the symmetry and textures in thin smectic films is relevant to understanding and optimizing the static and dynamic behavior of liquid crystals in flat panel display devices. The broader educational impact of this kind of research involving physics, chemistry and biology provides an excellent training ground for students from high school through post-doctoral training.