Fast ac electro-osmotic micropumps with nonplanar electrodes

This letter demonstrates dramatic improvements in flow rate and frequency range over conventional planar ac electro-osmotic (ACEO) pumps by exploiting three-dimensional (3D) stepped electrodes. A 3D ACEO pump was fabricated by electroplating steps on a symmetric electrode array and tested against a state-of-the-art asymmetric planar ACEO pump in a microfluidic loop. For all frequencies (0.1–100kHz), the 3D pump had a faster flow rate, in some cases by an order of magnitude. Their experimental results suggest that, after some optimization, mm/s velocities will be attainable with alternating battery voltages, which presents an exciting opportunity for microfluidics.