Multiphysics Modeling and Parametric Optimization of Janus Particle Wheel Microactuators Under Alternating-Current Induced-Charge Electrophoresis

Electrokinetic actuation enables non-contact fluid transport and particle manipulation in microfluidic devices. Induced-charge electrokinetics (ICEK) is particularly attractive for AC-field actuation because it can generate strong electrohydrodynamic motion without fixed surface charges. Here, we investigate the rotation of metallodielectric Janus-particle (JP) wheels using a transient, fully coupled reduced-order two-dimensional multiphysics model incorporating moving-mesh solid mechanics, viscous flow with induced-charge electroosmotic (ICEO) slip, and resistor–capacitor (RC) charging of induced electrical double layers. The model identifies the frequency range for stable counterclockwise rotation and clarifies the effects of applied voltage, connecting-rod geometry, JP radius, electrolyte conductivity, and JP number. Under the conditions examined, the rotation is dominated by ICEO slip on the JP metal surfaces, while AC electroosmosis (ACEO) and dielectrophoretic (DEP) torque provide secondary contributions. Stable continuous rotation requires at least three JPs, and the three-JP wheel gives the highest time-averaged angular velocity among the tested configurations, reaching 26.2 rad/s at a field strength of 20 V/mm. Increasing electrolyte conductivity shifts the characteristic rotation frequency upward and decreases the peak speed, whereas the effects of JP radius are non-monotonic. These results provide design guidance for ICEK-based microfluidic actuators and microrobots.