High pressure electroosmotic pump packed with uniform silica nanospheres

We report a novel electroosmotic pump fabricated on a plastic chip. Electroosmosis is one of electrokinetic phenomena and used as a precise liquid handling technique in some microfluidic devices. Electric double layer (EDL) between a channel wall and an electrolyte plays an important role in producing electroosmotic flow. When the net charge of EDL migrates, it carries the rest of the electrolyte due to the shear viscosity. The use of parallel narrow channels is a pathway to the more effective electroosmotic pumps since we can increase the net charge of EDL. We fabricated a plastic chip that confined uniform silica nanospheres within the channel, and tested its performance. We obtained the maximum flow rate 0.47 /spl mu/L/min and the maximum pressure 72 kPa when applied 3 kV to the electroosmotic pump.