Streaming Electric Field, Electroviscous Effect, and Electrokinetic Liquid Flows in the Induced Pressure-Driven Transport of Active Liquids in Narrow Capillaries

In this paper, we develop a theory for studying the electrokinetic effects in a charged nanocapillary filled with active liquid. The active particles present within the active liquid are self-driven and enforce a circumferentially arranged polarization field. Under such circumstances, there is the development of an induced pressure-gradient-driven transport dictated (similar to diffusioosmotic transport) by the presence of an axial gradient in the concentration of the active particles. This pressure-driven transport has a profile different from the standard Hagen-Poiseuille flow in a nanocapillary. This induced pressure-driven flow drives electrokinetic effects, which are characterized by the generation of a streaming electric field, associated electroosmotic (EOS) transport opposing pressure-driven flow, and electroviscous effect. We quantify these effects as functions of dimensionless parameters that vary inversely as the strength of the activity-induced pressure-driven flow and salt concentrations. Overall, we anticipate that this paper will draw immense attention towards a new type of activity-induced pressure-driven flow and associated electrokinetic phenomena in charged nanoconfinements.