Folded dielectric elastomer actuators

Abstract

Polymer-based linear actuators with contractile ability are currently demanded for severaltypes of applications. Within the class of dielectric elastomer actuators, two basicconfigurations are available today for such a purpose: the multi-layer stack and the helicalstructure. The first consists of several layers of elementary planar actuators stacked inseries mechanically and parallel electrically. The second configuration relies on a couple ofhelical compliant electrodes alternated with a couple of helical dielectrics. The fabricationof both these configurations presents some specific drawbacks today, arising from thepeculiarity of each structure. Accordingly, the availability of simpler solutions may boostthe short-term use of contractile actuators in practical applications. For this purpose, anew configuration is here described. It consists of a monolithic structure madeof an electroded sheet, which is folded up and compacted. The resulting deviceis functionally equivalent to a multi-layer stack with interdigitated electrodes.However, with respect to a stack the new configuration is advantageously notdiscontinuous and can be manufactured in one single phase, avoiding layer-by-layermulti-step procedures. The development and preliminary testing of prototypesamples of this new actuator made of a silicone elastomer are presented here.