Contractile dielectric elastomer actuator with folded shape

Linear dielectric elastomer actuators with contractile ability are demanded for several types of applications. In order to achieve such a goal, two basic actuating configurations are today available: the multilayer stack and the helical structure. The first consists of several layers of elementary planar actuators stacked in mechanical series and electrical parallel. The second relies on a couple of helical compliant electrodes alternated to a couple of helical dielectrics. The fabrication of both these configurations presents today some specific difficulties, arising from the peculiarity of each structure. Even though successful implementations have been reported and further improvements are currently in progress, the availability of simpler solutions would boost the short-term use of contractile actuators in practical applications. In order to propose a viable alternative to the present configurations, a new structure is here described. It is designed to obtain a contractile monolithic actuator, starting from a planar electroded sheet, which is then folded up. The resulting compact structure is equivalent to a multilayer stack with interdigited electrodes. With respect to the conventional multilayer stack, the new configuration is advantageously not discontinuous and can be manufactured in one single phase, avoiding layer-by-layer multistep procedures. The current developmental stage of this new actuator with a silicone elastomer is here presented.