Dynamic Motion Control of Topological Defects in Nematic Liquid Crystals by Chemically Patterned Surfaces

The existence of topological defects (TDs) is ubiquitous in nature due to their occurrence at broad spatiotemporal scale, for instance, in subatomic particles or cosmology. The analogous nature of these defects makes it possible to apply the mathematics describing TDs formation and evolution to different disciplines and length scales. Liquid crystals have been considered as an ideal system for the defects investigation, due to the birefringence phenomena of LCs enabling direct visualization of such topological defects and a straightforward analyzation process. In addition to characterizing and analyzing the equilibrium morphology of LC topological defects, it is also of great interest to track and control the formation and annihilation of defects during thermodynamic processes. However, controlling the dynamic behavior of formed defects remains a challenge. Here, we confine the nematic LCs in a cell exhibiting surfaces with periodic anchoring conditions and surface topography at the interface of homeotropic and degenerate planar anchoring stripes. We explore the effects of patterned surface characteristics on defects dynamic motion, stabilization and annihilation by controlling the width of homeotropic/planar stripes along with the periodicity.