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Perry Ellis

Cholesteric Liquid Crystals in Spherical and non-Spherical Curved Spaces

Recent work in our group has explored nematic liquid crystals in spherical (and most recently), non-spherical curved spaces. We are now extending our work to cholesteric, or chiral nematic, liquid crystals. This work will allow us to futher explore and probe the effect of topology and ordering in physical systems. For example, our work with nematics exhibited and confirmed the Poincare-Hopf theorem; we hope our current projects with cholesteric materials will be able to achieve similar results. Our work is also motivated by the potential to create optically and electro-optically responsive materials for photonics applications. For example, there is interest in utilizing preferential binding to topological defects to create self-assembled supramolecules of goemetrically constrained nematics and cholesteric liquid crystals.

The addition of chirality to the nematic phase in constrained geometries enriches the system and introduces many interesting questions not found in achiral materials. We must now consider not only nematic packing, but also the interplay between a constained geometry and the twisting power of our material. For example, given a set nematic packing in a monodisperse cholesteric emulsion, we are able to explore defect structures from the twisted bipolar all the way to the Frank-Pryce structure simply by manipulating the pitch of our material.

While currently our investigation has only covered spherical emulsions of cholesteric liquid crystal, we intend to explore spherical shells and toroidal/higher genus geometries as well.