Pad printing 1-10 mm thick elastomer membranes for DEAs

We present a technique for stamping patterned silicone elastomer membranes with thicknesses ranging from 1 to 10 um. Silicone elastomers are becoming the material of choice for dielectric elastomer transducers. The variety of readily available materials, their versatility in terms of film thicknesses and their excellent mechanical properties have made them a very appealing alternative to the widely used acrylic elastomer VHB from 3M. Silicone films are typically blade casted or spin coated, two complementary techniques allowing for large-area (> 10 cm x 10 cm) and ultra-thin (< 1 µm) membranes respectively. By comparison, membranes up to 5 cm x 5 cm in area and with thicknesses ranging from 1 to 10 µm can be fabricated with a stamping technique. Unlike blade casting and spin coating this technique can be used to directly pattern (in-plane) the membrane to any desired shape, thus providing great design flexibility. We demonstrated in prior work that stretchable electrodes can also be patterned by stamping. Combined with the ability to pattern silicone membranes, it enables the stamping of functional structures such as dielectric elastomer actuators (DEAs) with high level of integration (vertical integration). In this contribution we detail our fabrication process and highlight the important parameters. As a proof of concept we characterized a stamped DEA, as well as a stamped vertical electrical connection for layers interconnection.