Silicone Elastomers with High-Permittivity Ionic Liquids Loading

The most obvious challenge facing current dielectric elastomers (DEs) is the high driving voltages necessary to activate them, and so an effective way to overcome this shortcoming is to increase their dielectric permittivity. Herein, high-permittivity dielectric elastomer materials were prepared by synthesising silicone elastomer loaded with ionic liquids (ILs). The influence of the structure and the amounts of ILs on the material properties was discussed, and important properties for material applications as DEs, such as dielectric permittivity, gel fraction and mechanical properties, were also investigated. It was found that 1-butyl-3-methylimidazolium hexafluoroantimonate (BmimSbF6) is the most suitable IL for the given system. The dielectric permittivity of the material with 90 phr BmimSbF6 was 3.2 times higher than that of the pristine silicone elastomer, while the dielectric permittivity of pure silicone elastomer and elastomer loaded with ILs decreased in line with increased temperature in all cases. The Young's modulus decreased in line with the increasing amount of BmimSbF6 in the elastomer, as expected. A simpler figure of merit (F*om) for actuators was used, and the F*om of the elastomer with a 90 phr IL loading was 10.40, thereby indicating that the material has a great advantage when used in actuators.