Dynamical and Structural Studies of Liquid Crystal Phases

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This award by the Biomaterials program in the Division of Materials Research to University of Colorado Boulder is to study Dynamical and Structural Studies of Liquid Crystal Phases, and is co-funded by the Solid State Chemistry program in DMR. With this award, PI will study liquid crystal (LC) phases of nanoscale duplex DNA with only a few (6 - 6) base pairs, physics of tubule forming diacetylenic phospholipids, freely suspended films of bola amphiphiles, the dynamics of topological defects in freely suspended films, multi-layer islands on monolayer films, polarization-modulated phases of bent-core molecules, and the organization of liquid crystals on micro- and nano-patterned surfaces. The project will probe the LC phase structures, the molecular adhesion mechanism leading to anisotropic LC forming aggregates, and the effects of DNA base pair choices. Liquid crystal phases proposed to study included 2D nematic to 2D smectic A phase transitions; smectic of bent-core molecules with triclinic symmetry; collective dynamics of layer to layer interfaces in smectic films; and X-ray and optical methods to study structural aspects of these LC phases. LCs are phases stabilized by weak interactions and characterized by various degrees of fluid ordering, a combination enabling self-organization and annealing out to mesoscopic and macroscopic length scales into structures that are easily manipulated by agents such as fields and surfaces. These studies not only makes liquid crystals technologically useful, but also leads directly to the central role played by liquid crystals and liquid crystal organizational themes in the development of self-assembled supermolecular systems. Thus liquid crystals continue to present problems and opportunities of extraordinary interest in condensed mater science. The proposed work focuses on the study of their structure and dynamical behavior using optical microscopy, light scattering, synchrotron-based x-ray diffraction, and electron microscopy, addressing issues in the physics of a variety of soft matter systems.%%%With this project, collaborations with industry will be pursued in the area of LC alignment and bent-core molecular nonlinear optics. The training of graduate students will be a priority of this project and the PI plans to develop the University of Colorado Liquid Crystal Science and Technology Program with a focus on the development of a soft-matter graduate laboratory course. In addition, the PI will continue to add new activities with the Materials Science from CU program, a science education enrichment program presenting hands-on classes to Colorado students, and designed to teach physical science concepts using the current understanding of materials. For K-6 students and their parents, the PI plans to serve as a "Wizard" in the Liquid Crystal Wizards Show, which has been performed in Boulder and rural areas of Colorado over the past several years.