A robust dual-membrane dielectric elastomer actuator for large volume fluid pumping via snap-through

Abstract

A pressurized dielectric elastomer (DE) diaphragm under electrical actuation can experience snap-through large deformation due to electromechanical instability, which was shown to be a promising mechanism for large volume fluid pumping. However, snap-through actuation in a DE fluid pump will not occur when the inlet pressure to the pump is small and cannot be robustly utilized for different applications. To solve this problem, in this study, we proposed a dual-membrane DE pump design featuring an active DE membrane interacting with a passive elastic membrane. This design enabled snap-through of the DE membrane over a wide range of inlet pressures, making it feasible for large volume fluid pumping even at low pressures. Merits of this dual-membrane DE actuator design were experimentally verified; for example, the pumping volume of the dual-membrane DE pump could be as large as 3944% of the pumping volume of the conventional single-membrane DE pump. We further proposed an analytical framework to describe the mechanism of the dual-membrane DE fluid pump, involving the superimposition of the pressure-volume curves of the active and passive membranes. The theoretically predicted equilibrium states agreed well with experimental observations. Findings in this study will broaden the applications of the DE actuator in scenarios where a large pumping volume is needed over a wide range of pressures.