Influence of Array-Type Surface-Induced Charges on Micromixing in Pressure-Driven Micromixers

Electrohydrodynamic vortex architectures originating from polarization-surface-induced charge localization demonstrate significant interfacial augmentation capabilities in low Reynolds number (Re) laminar flow regimes. This study uses conductive plate arrays to systematically investigate the multiphysical coupling mechanisms that integrate spatially heterogeneous charge polarization patterns, vortex-induced electroconvective phenomena, and pressure-driven flow (PDF) transport across micronanofluidic interfaces. Results establish that optimal mixing performance arises from the dynamic equilibrium between PDF-induced inertial forces and electroosmotic slip velocities governed by induced zeta potentials. At low-PDF conditions, that is Re = 0.1, interplate array spacing and staggered configurations critically regulate vortex dynamics: reduced spacing amplifies localized electric field intensities and slip velocities, while horizontal offsets (D = 50 μm) generate asymmetric vortex coalescence, achieving nearly perfect mixing with a mixing index of 0.97. Vertical array spacing parameters (Lp = 60 μm) enhance chaotic advection through extended vortex perturbation domains, whereas rotational configurations (α = 30–40°) optimize interfacial deformation via bidirectional electrokinetic actuation. However, when Re increases to 5, high PDF suppresses electrokinetic-vortex coupling, reducing mixing performance to diffusion-limited levels. Parametric analysis identifies critical geometric thresholds for field asymmetry development, revealing that staggered arrays simultaneously minimize pressure intensification and maximize charge redistribution efficiency. This work establishes a mechanism framework for manipulating vortices through array-configured surface charges, advancing the understanding of microscale mass transfer under the combined action of electrohydrodynamic forces.