Research on the microparticles collection caused by AC electroosmosis

The low concentration of microparticles collected in micro-electromechanical systems (MEMS) was studied. It was found in experiments that when applying low voltages and low frequencies on symmetrical electrodes, microparticles could be collected in a fixed area. Based on AC electric field, the authors established a 2D model of the symmetrical electrodes and a homotactic circuit, deduced the microfluidic velocity expression, and analyzed microparticle velocities based on their dielectrophoresis, buoyancy and gravity. By means of a numerical simulation, the collection position of the microparticles and the influence of dielectrophoresis were analyzed and the simulation was compared with the experiment. The study showed that AC electroosmosis is the dominant force when low voltages and frequencies are applied.