Asymmetric Induced-Charge Electroosmotic Flows around Partially Conducting Cylinders in Shear-Thinning Fluids

Abstract

Abstract In this two-dimensional computational study, induced-charge electroosmosis (ICEO) around a half-conducting Janus cylinder immersed in a power-law shear-thinning electrolyte is considered within a fully coupled Poisson–Nernst–Planck–Stokes (PNP-Stokes) formulation, with the selected range of the flow-behavior index providing a systematic framework to investigate the influence of shear-dependent viscosity on ICEO-induced transport. The asymmetric surface conductivity of the Janus cylinder breaks the classical dipolar symmetry of ICEO, producing localized polarization zones, unequal counter-rotating vortices, and strongly modified azimuthal velocity distributions. Incorporation of a power-law rheological model demonstrates that shear-thinning behavior significantly amplifies the induced near-surface flow, enlarges recirculation regions, and enhances convective ion transport. The simulations show that the coupling between nonlinear double-layer polarization and shear-dependent viscosity leads to a nonlinear voltage-velocity response that deviates from the classical quadratic ICEO scaling and enhances local ionic mixing. The influence of applied potential (ϕ* = 0.1–3), Debye parameter (κ = 6–10), and flow-behavior index (n = 0.6–1) on the induced flow, charge distribution, current density, and mixing performance is systematically examined. These results demonstrate that both surface-conductivity asymmetry and fluid rheology influence nonlinear ICEO transport, providing insight into the design and control of electrokinetic flows in microfluidic systems involving non-Newtonian electrolytes.

The authors' abstract, as published at the source. Industrial & Engineering Chemistry Research, 2026 · DOI ↗