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Center for Nonlinear Studies |
Disclinations are pervasive in both passive and active nematic liquid crystals. In the former, they can be used to align and propel colloidal particles, actuate surfaces, and transport biomaterials; while in the latter they spontaneously nucleate and recombine, facilitate density gradients, and promote extrusion of nematogens and layered growth of the material. In this talk, I will describe our recent efforts to understand disclination structure in both 2D and 3D environments. First, motivated by experiments showing unusually large and anisotropic defect cores, I will describe a self-consistent field theory which is necessary to model both elastic anisotropy and biaxiality in nematic systems. Computational application of this theory and direct comparison with experiments show that elastic anisotropy leads to an anisotropic defect morphology. I will also introduce a disclination density tensor as a means of identifying and characterizing line disclinations in 3D. This tensor is connected to the defect topology and geometry and can be used to define a kinematic defect velocity via the topological charge current. I will show several numerical and analytical applications of this velocity.
Host: Nick Hengartner