Chemiosomotic flow in a narrow fluidic channel

Abstract

A liquid volume containing dissolved solutes moves through a charged nanofluidic channel under the influence of the concentration gradient of the solutes, non-trivially modulated by the electrostatic interaction between ionic liquid and charged surface. The available studies in this paradigm primarily focus on either of diffusioosmosis or electrodiffusioosmosis modulated physicochemical hydrodynamical phenomenon, essentially to obtain a net throughput at the overlapping scales. Here, we develop a theoretical model that accounts for the induced pressure gradient stemming from the concentration gradient of the solutes alongside the axially varying electrical double layer effect in tandem and characterizes the chemiosmotic flow in a reservoir-connected nanofluidic system. Starting from the potential distribution developed due to the solute gradient modulated electrical double layer effect, we look at the effect of pertinent physicochemical parameters and their eventual manifestations onto the purely chemiosmotic transport, aptly described in this endeavor. We analytically establish a chemiosmotic velocity scale from a macroscopic viewpoint, relating flow velocity with the relevant parameters, and uniquely measuring the magnitude of chemiosmotic velocity. A closer as well as consistent agreement on theoretical predictions with the corresponding full-scale simulated results, both in the limit and beyond the Debye-Huckel approximation, substantiates the efficacy of our theory.