Computational probe of current responses derived from mass-transport through interconnected pore structures in 3D-printed milli fluidic devices with channel band electrodes

Abstract

This computational study investigates steady-state current responses in Fused Deposition Modeling (FDM) 3D-printed milli fluidic devices with channel band electrodes under laminar flow conditions. While conventional microfluidic devices are well-characterized using Levich and Thin Layer analytical models, 3D-printed platforms exhibit inherent porosity creating complex current behavior inadequately described by Levich and Thin Layer equations alone. After a mesh convergence study determined appropriate mesh conditions, four device designs considering porous network structure and pore proximity to the electrode were computationally probed. Analysis of these simulations incorporated design and hydrodynamic dimensionless parameters to characterize mass-transport regimes. Previously reported General and Transition analytical models as well as Levich and Thin Layer models were applied for current prediction and mass-transport analysis. As a result, the highest and lowest currents were obtained for a pore continuous to the electrode and a complex pore network structure, respectively. Velocity and concentration profiles reveal that interconnected pore structures and pore – electrode proximity create regions where diffusion, convection, or both transport regimes predominate simultaneously in the same device configuration. While general and transition mass-transport models accurately characterize designs with simpler porous network structures, they diverge under the structural mass-transport constraints of a design with a more complex porous network structure; this identifies critical limitations for existing theory and underscores the need for future framework refinements. Progress in this direction is essential to optimize device design and improve analytical performance in electrochemical sensing applications that employ FDM 3D-printed milli fluidic devices.