Geometrical frustration of chiral ordering in cholesteric droplets

Abstract

Frustration of chiral ordering is explored in cholesteric liquid crystal droplets with planar degenerate anchoring using numerical modeling. Droplets of variable pitches are studied, demonstrating the role of a gradually increasing cholesteric pitch and the corresponding equilibrium structures. All previously known structures are identified but with notable differences. The structures presented with director fields are complemented with a detailed description of the defect regions. The characteristic half-diameter +2 disclination from previous studies is found to be in fact a double-helix of two λ+1 disclination lines, whereas the full-diameter +1 disclination is composed of an alternating series of τ−1/2 and λ+1/2 disclination rings. Finally, two new meta-stable cholesteric structures -Lyre and Yeti- are found, which are characterised by complex compositions of cholesteric disclinations.