Flow induced deformation of defects around nanoparticles and nanodroplets suspended in liquid crystals

Abstract

A three-dimensional molecular theory is used to describe the effect of flow on the defects that arise around nanoparticles and nanodroplets suspended in a nematic liquid crystal. It is observed that flow displaces the Saturn ring line defect that forms around a nanoparticle at equilibrium in the upstream direction; it is eventually closed by the flow and becomes a Hedgehog point defect. In contrast, the Saturn ring that forms around a nanodroplet is slightly displaced in the downstream direction. Experimental measurements of defects around nanoparticles have not been reported in the literature. In the absence of experiments, the validity of theoretical predictions is assessed through a direct comparison to results of many-body molecular dynamics simulations of a coarse grain liquid crystal model. Theoretical predictions and molecular simulations are in quantitative agreement, thereby lending credibility to the predictions presented in this work and suggesting that flow can be used to manipulate defect structure and aggregation of nanoparticles in nematic liquid crystals.