Pump it up

Abstract

We report on the use of zipping actuation applied to dielectric elastomer actuators to microfabricate mm-sized pumps. The zipping actuators presented here use electrostatic attraction to deform an elastomeric membrane by pulling it into contact with a rigid counter electrode. We present several actuation schemes using either conventional DEA actuation, zipping, or a combination of both in order to realize microfluidic devices. A zipping design in which the electric field is applied across the elastomer membrane was explored theoretically and experimentally. Single zipping chambers and a micropump body made of a three chambers connected by an embedded channel were wet-etched into a silicon wafer and subsequently covered by a gold-implanted silicone membrane. We measured static deflections of up to on chambers with square openings of 1.8 and 2.6 mm side, in very good agreement with our model.

Mm-size bistable zipping dielectric elastomer actuators for integrated microfluidics

“…We previously investigated anisotropic crystalline etching of silicon by potassium hydroxide (KOH), which yields pyramidal-shape chambers with a large fixed sidewalls angle of 54.7°. We could obtain a maximal out-of plane deflection of 300 μm on 2.6 mm side chambers covered by a membrane patterned with an Au ion-implanted electrode on top, not reaching the fully deflected shape (525 μm deflection) [10] . In this work, we present a new generation of devices which have conical-shape machined chambers in aluminium.…”

“…As presented in our previous work [10,11] , DEA zipping actuators are a variant of the traditional DEA operation mode inspired by silicon MEMS zipping devices [12] . Instead of having two compliant electrodes that squeeze the elastomer and produce a thickness compression and lateral expansion [1] , zipping DEAs attract one single compliant electrode toward a rigid one.…”

“…We already proposed a model which is able to predict the static displacement of membranes zipping in pyramidal-shape chambers with 54.7° sidewalls angle (corresponding to α) [10] . We kept the same approach, changing only the chamber geometry from a pyramidal shape into a conical one.…”

“…Apart from the large strains, this application imposes specific requirements on the actuator's characteristics: out-of-plane motion, sealing of embedded channels, and guaranteed complete deflection by a bistable operation mode. We proposed previously a variant of DEAs inspired by silicon MEMS zipping devices that precisely meets these requirements [10] . As a demonstration of the feasibility of DEA-powered MLSI chip, we want to develop a peristaltic micropump composed of three in-line zipping DEAs.…”

“…A promising application of DEAs is to replace the pneumatic actuators of microfluidic large-scale integrated chips (MLSI) [9] in order to enable electrically-powered portable lab-on-chips [10] as the current MLSI systems requires large external pumps and compressed air sources. Apart from the large strains, this application imposes specific requirements on the actuator's characteristics: out-of-plane motion, sealing of embedded channels, and guaranteed complete deflection by a bistable operation mode.…”