Sparse Representation in Redundant Systems

CSIC Building (#406), Seminar Room 4122.
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Nematic Nano-composites: Flowing Toward Performance Properties

Professor M. Gregory Forest

Institute for Advanced Materials, NanoScience and Technology, University of North Carolina at Chapel Hill

Abstract:   Nematic polymers are high aspect ratio macromolecules, either rods or platelets. They are utilized in high performance materials for a diversity of properties including mechanical, thermal, barrier, and electrical. Such macromolecule ensembles in solutions, and similar geometric colloidal suspensions, exhibit remarkable response to shear-dominated flow. Bulk phases undergo an isotropic-nematic first order phase transition. Weak flows such as shear drive this transition to create a myriad of responses, including steady and unsteady bulk modes. The result for these nano-composite films is a combination of anisotropy and heterogeneity---in the performance features of materials, which is somehow dictated by the morphology of the high aspect ratio macromolecular ensemble. This "map" between composition, flow conditions, and ultimate material properties is the basis of the lecture. Progress to date, and the challenges ahead to theory and computation, will be highlighted.