Integration of dielectric elastomer stack actuators into micro systems

Abstract

Using dielectric elastomer stack actuators the electrical contact to each conducting layer is a major concern. In order to integrate these actuators inside micro systems e.g. microfluidic systems compatibility to micro fabrication processes is required. The contact resistance and number of connected layers influence the overall actuator performance directly. Lower number of active electrodes decreases the generated deformation of the actuator. High contact resistance has a negative impact on the dynamic actuator behavior. For conventional interconnection processes with copper wires, the contact ratio is in the range of 60% to 80%, depending on the film thickness of the dielectric layer. Furthermore, this process is not compatible to standard micro fabrication technologies. In this paper we evaluate a process based on electroplating for connecting dielectric elastomer stack actuators and present a measurement system to characterize the number of connected layers. The performance of an electroplated contact is defined by the number of connected layers and the contact resistance between electroplated copper studs and graphite electrodes. It depends on different parameters like the cross sectional area of the electrode layers for connection and therefore on the layer thickness. Using multiple contacts instead of a single one the performance of the contact can also be positively influenced.