Two-phase interdigitated microelectrode arrays for electrokinetic transport of microparticles

In this paper, we demonstrate long-range particle transport using linear two-phase interdigitated arrays with electrodes of equal size but with asymmetric spacing between them. We report net motion of 6 mu m polystyrene spheres in an aqueous electrolyte and characterize the dependence of particle velocity on frequency, potential and phase, and show consistency with previous experiments that involved four-phase arrays producing AC electroosmotic and dielectrophoretic forces. We explore the effect of increasing the asymmetry of the electrode spacing and show that this decreases the performance of the array. We also examine the effect of increasing the overall scale of the array while maintaining geometric proportions and particle size and report that this also decreases the performance. We compare our results to previous analytical theoretical predictions and find general agreement.