A method to fabricate monolithic dielectric elastomer actuators

Dielectric elastomer actuators (DEAs) are usually composed of elastomeric membranes and electrodes, which are separately fabricated and patterned. In this contribution, we describe a method to monolithically fabricate DEAs that combines molding and microfluidic technologies. In our process, microfluidic channels having desired electrode geometry are formed in a single, monolithic elastomeric matrix, and then liquid conductive material is injected into it. This fabrication method is expected to be effective for making DEAs with multiple sets of electrodes as they can be formed at once. In addition, it potentially enables easy fabrication of DEAs with complicated shapes. We prove the concept through the fabrication and characterization of a DEA that contains a single set of electrodes. A PDMS (Dow Corning, Sylgard 184) and a liquid metal (EGaIn) are chosen as the materials for the elastomeric matrix and the electrodes, respectively. Polylactic acid (PLA) is used as the molding parts made by a commercial FDM 3D printer. After curing the PDMS matrix with microfluidic channel, EGaIn is injected using a vacuum filling method, forming a monolithic DEA ready to be tested. The fabricated DEA has an active electrode area of 10 mm x 10 mm with a gap between the electrodes of 0.5 mm. During the characterization, the device exhibited actuated deformation of 13.2 um at applied electric field of 9 V/um.