Electrode filling using capillary action of 3D printed elastomer microchannels

Soft polymer actuators are in increasing demand due to their more fluid like motion and flexibility when actuated than compared with rigid actuators, which makes them valuable in diverse engineering applications. One of the main types of soft polymer actuators is the dielectric elastomer actuator, whose working principle is to apply a voltage potential difference between electrodes to reduce the thickness of the elastomeric material while expanding its area. This paper looks at manufacturing a micro soft polymer dielectric elastomer actuator utilizing two-photon polymerization 3D printing. The actuator contains micro channels that are filled with an electrode by using capillary action. A complex helical geometry is designed, printed, and tested for electrode filling capabilities. Quite a few obstacles are described in this paper including the use of a newly released two-photon polymerization resin which has limited supporting resources, as well as the complex helical geometry having a large compliance that vastly complicates its fabrication, post-processing, handling, electrode filling, electrode integration, and actuation testing. However, these challenges are overcome by using the standard printing recipes currently available for the resins, adding electrode isolation layers, and printing thicker elastomer zones for more structural support. The results found solidify the approach of filling microchannels with electrodes through capillary action and lead to further the focus and creation of multi-functional micro soft actuators.