Silicone elastomers with high-permittivity ionic liquids loading

Dielectric elastomers transducers (DETs) represent a promising transducer technology, due to their excellent ability to undergo large and reversible deformations under an applied electric field.[1] The most obvious challenge facing current DEs is the high driving voltages necessary to drive them,[2] and so an effective way to overcome this shortcoming is to increase the dielectric permittivity of the applied elastomers.[3] Ionic liquids (ILs), which have gained significant attention in recent years, have high permittivity but also high conductivity. It is therefore interesting to blend ILs into elastomers to increase their dielectric permittivity while focusing on maintaining the non-conductive nature of the elastomers.[4] Herein, high-permittivity silicone elastomers were prepared from blending in ILs. The influence of the structure and the content of ILs on the material properties was discussed, and important properties for material applications as DETs, 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 elastomer system. The dielectric permittivity of the elastomers increased with the increasing content of BmimSbF6. The Young’s modulus decreased in line with the increasing content of BmimSbF₆, as expected. A simple figure of merit (F*_om) for actuators was used and the resulting F*_om of elastomer with 90 phr IL loading is 10.40 thereby indicating that the material has a great advantage when used in actuators.