SGER: Microfluidics as a Platform to Study Confinement of Complex Fluid Microstructures at Intermediate Length Scales

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PROPOSAL NO.: CTS-0527909PRINCIPAL INVESTIGATORS: SHELLEY ANNAINSTITUTION: CARNEGIE MELLON UNIVERSITY SGER: MICROFLUIDICS AS A PLATFORM TO STUDY CONFINEMENT OF COMPLEX FLUIDMICROSTRUCTURES AT INTERMEDIATE LENGTH SCALESThis is an exploratory research program to investigate the structure of liquid crystalline materials when confined at intermediate length scales, well above the molecular length scale, but small enough to significantly impact the defect microstructure. Recent experimental studies suggest that medium range confinement in microfluidic channels with well-defined surface anchoring conditions can lead to the formation of ordered arrays of defects. This new method for generating controlled defect structures offers a unique opportunity for studying the hydrodynamics of smectic materials, and for exploiting the competition between confinement, surface anchoring, and flow to synthesize new materials. This work has the potential to profoundly impact the study of the dynamics of complex liquids, as it will enable quantitative observations of defect dynamics in systems with precisely defined initial conditions. The results of these studies have the potential to impact a very wide range of new and mature applications from displays to pharmaceuticals, as well as to advance a fundamental understanding of the fluid dynamics of self-organizing materials. Preliminary studies will focus on small molecule thermotropic liquid crystals, which exhibit phase changes with temperature and derive their structures solely from packing and anisotropic dispersion forces. The intellectual merit of this work is the coupling between the physics of liquid crystalline self-organization and the mechanics of flow in geometries with dimensions much larger than molecular dimensions, but small enough to strongly influence the defect microstructure. A detailed understanding of this coupling will lead to a greater understanding of the impact of dynamics on self-organizing materials. The broader impact of this work lies in the enhancement of science and engineering infrastructure through development of microfluidics tools for research and education. Modifying these tools for outreach activities will help bring fluid mechanics education to K-12 students and teachers, and the public.