Microfluidic Engineering

The ability to generate high pressures using electrokinetic pumping of liquid through porous media is reported. Pressures in excess of 8000 psi have been achieved using capillaries (< 100 {micro}m i.d.) packed with micron-size silica beads. A model is presented which accurately predicts absolute pressures, flowrates and power conversion efficiencies as well as the experimentally observed dependencies on pore size, applied electric field and electrical properties of the fluid. This phenomenon offers the possibility of creating a new class of microscale fluid devices, electrokinetic pumps and valves, where the performance improves with scale-down by taking advantage of microscale processes