Modeling of fully hermetic electrostatic microfluidic valve actuator with increased displacement

Abstract

The combined static displacement of specifically arranged microscale electrostatic elements was analyzed to investigate a fully hermetic, perpendicular-to-plane type of electrostatic microactuator. The concept of asymmetric perimeter-supported electrostatic plates is introduced featuring softened partial clamping of plate perimeter. When engaged by an electrostatic field, asymmetrically clamped square plates tend to develop a rotating momentum, which is transferred to the background plate. Therefore, larger displacement range of the combined membrane actuator is possible by increasing of the number of elementary electrostatic cells, but not the electrostatic gap. It was shown by finite element modeling that a combination of 400 asymmetric electrostatic cells over a square background plate (the membrane actuator), roughly measured at 1 mm2, has a potential to produce a static deflection at the central point of the membrane, that is perpendicular to the plane, reaching 2 µm at 45 V or up to 8 µm at higher voltages. This result was supported by a physical model built at 1000:1 scale using stereolithographic three-dimensional printing. A potential application of the proposed perpendicular to plane membrane actuator is microfluidic systems.