Dielectric elastomer actuators with enhanced permittivity and strain

The impact of the modification of silicone rubber with barium titanate particles on the permittivity and hence on the performance of dielectric elastomer actuators has been investigated. Barium titanate powders with different particle sizes in the micrometer and nanometer range were used in this study. The mechanical properties of the composite materials in terms of the Young's modulus in tension and compression load as well as the viscoelastic behavior in shear load were experimentally determined. Additionally, the electric properties like permittivity, specific conductivity and electric breakdown field strength were evaluated. Model film actuators with the modified silicone material were prepared and their actuation strain was measured. With a concentration of 20 vol.% barium titanate particles, an enhancement of the permittivity of 140 % and an increase of the actuation strain of about 100 % with respect to the unmodified material could be achieved. Furthermore, first multilayer actuators were manufactured with an automatic spin coating process and their permittivity and strain were measured. The results of these investigations are in good agreement with the data of the experiments with single layer dielectric elastomer films.