A comparison between silicone and acrylic elastomers as dielectric materials in electroactive polymer actuators

Soft elastomers, mostly silicones and acrylics, are interesting candidates as dielectric materials in electroactive polymer actuator technology. Generally, characteristics like large strain, high stress, high energy density, good efficiency and high response speed are required for actuator applications. However, some of these material properties may be contradictory. For this reason a comparison between Dow Corning silicone and 3M acrylic elastomers was made based on a set of six electromechanical tests for actuator applications. The silicone elastomer shows a fast electromechanical response (3 s) with good reproducibility and the dissipated work is negligible and not frequency dependent. It also shows a stable mechanical behaviour over a wide temperature range. In contrast, the acrylic elastomer shows a slow electromechanical response with poor reproducibility. The dissipated work of the acrylic elastomer is significant: a strong frequency and temperature dependency of the dissipated work is observed for this material. The Dow Corning silicone (DC 3481) is a better material for many applications, where activation strains of less than 10% are sufficient. However, in applications where higher strains are required, it might be obligatory to use acrylic elastomers, because only these have the potential for use with activation strains beyond 10%. The electrical activation of a circular specimen is most useful in order to evaluate a material as a dielectric in electroactive polymer actuators. (C) 2009 Society of Chemical Industry