Large stroke electrostatic actuated PDMS-on-silicon micro-pump

We introduce a large stroke electrostatic micro-pump made with a thin PDMS diaphragm embedded with thin-film metal electrodes and bonded over a smoothly shaped Si substrate that acts as the counter electrode. The thin PDMS layer creates a highly compliant diaphragm. The spline-shaped substrate height significantly reduces electrostatic actuation voltage, and is refined in its smoothness by a modification to conventional grayscale lithography for Si MEMS. Combining the effects of the compliant diaphragm and the “zipper” electrode gap, a diaphragm displacement of 100 μm is achieved, giving a displacement volume of 1 μL/stroke and a pumping rate of 60 μL/min at 1 Hz.