The mechanism for large-volume fluid pumping via reversible snap-through of dielectric elastomer

Abstract

Giant deformation of dielectric elastomers (DEs) via electromechanical instability (or the “snap-through” phenomenon) is a promising mechanism for large-volume fluid pumping. Snap-through of a DE membrane coupled with compressible air has been previously investigated. However, the physics behind reversible snap-through of a DE diaphragm coupled with incompressible fluid for the purpose of fluid pumping has not been well investigated, and the conditions required for reversible snap-through in a hydraulic system are unknown. In this study, we have proposed a concept for large-volume fluid pumping by harnessing reversible snap-through of the dielectric elastomer. The occurrence of snap-through was theoretically modeled and experimentally verified. Both the theoretical and experimental pressure-volume curves of the DE membrane under different actuation voltages were used to design the work loop of the pump, and the theoretical work loop agreed with the experimental work loop. Furthermore, the feasibility of reversible snap-through was experimentally verified, and specific conditions were found necessary for this to occur, such as a minimum actuation voltage, an optimal range of hydraulic pressure exerted on the DE membrane and a suitable actuation frequency. Under optimal working conditions, we demonstrated a pumping volume of up to 110 ml per cycle, which was significantly larger than that without snap-through. Furthermore, we have achieved fluid pumping from a region of low pressure to another region of high pressure. Findings of this study would be useful for real world applications such as the blood pump.