Positioning of Cubic Shaped Particles with Different Edge Structures in Nematic Medium

Abstract

Liquid crystals (LC) are phases of matter that possess long range orientational order while maintaining fluidic properties. LCs have been shown to provide a medium that result in self-assembly of the colloidal particles through elastic interactions. One parameter that affects the positioning of the particles in LC medium is the edge sharpness of the particles. Simulation studies in the literature suggests that the edge sharpness of the particles directly affect the LC director profile at the vicinity of the particles, and playing a critical role in the formation and the shapes of the topological defects. This study provides a systematic study to show the effects of the edge sharpness on the orientation and the defect structure around the cubic shaped particles. The particles were shown to orient with their diagonal preferably parallel to the direction of the far field nematic director when the particles mediate planar anchoring. Whereas the particles with homeotropic anchoring did not exhibit strong preference in their orientation. We also showed defect structures to form around the particles with homeotropic surface anchoring. The defect structure around the particles with round edges were ring shaped, whereas the defects with S-shapes were formed around sharp-edged or truncated particles. The findings herein were found to be consistent with the simulations present in literature. The findings would find use in next generation materials for optics, photonics and responsive systems.