Charge-, salt- and flexoelectricity-driven anchoring control in nematics

We show that the design of electric double layers and flexoelectricity can be used to tune the surface anchoring in general nematic fluids. Specifically, we demonstrate for a nematic electrolyte that the surface anchoring strength can be efficiently controlled by the surface charge, bulk ion concentration and/or flexoelectricity, effectively changing not only the magnitude of the anchoring but also the anchoring type, such as from planar to tilted. This tuning is driven by the competing energetic-torque couplings between nematic director and the emergent electrostatic potential, due to surface charge, ions and flexoelectricity. Our findings propose a novel way of influencing surface anchoring by using electrostatic effects, which could be used in various aspects, including in the self-assembly of colloidal particles in nematic fluids, optical and display patterns, and sensing.