Numerical investigation of electro-osmotic flow in porous media and the induced film deformation

A multiphysics numerical framework is established using COMSOL Multiphysics to systematically investigate electro-osmotic flow (EOF) in porous media and the induced film deformation. Our study reveals the intrinsic correlation between electro-osmotic driving pressure and film deformation. Specifically, the applied electric field induces a bottom-up EOF within the porous layer, driving fluid accumulation in the upper chamber and resulting in a parabolic deformation profile of the flexible film. While the electric field force and hydraulic pressure scale linearly with voltage, the film deformation exhibits a power-law growth. We demonstrate that the electrode channel configuration serves as a key tool to modulate hydraulic impedance and accelerate the temporal response without compromising the steady equilibrium. Porosity governs the trade-off between driving force and hydraulic resistance. Raising the porosity from 0.5 to 0.7 reduces the maximum deformation from 0.25 to 0.21 μm but curtails the response time from 2 to 0.33 s. This work is intended to provide a foundational reference for the design of high-performance, compact flexible sensing devices.