High-permittivity silicone dielectric elastomers compatible with ionic liquid-grafted chloropropyl-silicone oil

Dielectric elastomers (DEs) can undergo very large spatial deformations in response to an externally applied electrical field, giving them significant potential as soft actuators. High-performance DEs are usually modified by high-permittivity additives, which are used to lower driving voltages. In this study, a novel high-permittivity soft additive (LMS-EIL) was developed via the combination of high-permittivity ionic liquid (IL) and chloropropyl-silicone, enabling good compatibility with the silicone matrix.

The relative dielectric permittivity of the novel silicone oil additive was 9×104 times higher at 0.1Hz compared to pristine chloropropyl-silicone oil. High-permittivity silicone elastomers were then achieved via incorporation of this novel IL-grafted chloropropyl-silicone oil. The relative dielectric permittivity of elastomers modified with 10 parts per hundred rubber (phr) LMS-EIL increased from 3.0 (pure film) to 22 at 0.1Hz, while the Young’s modulus decreased steadily with increasing LMS-EIL concentration.

A simplified figure of merit (Fom') was used to evaluate actuation performance, and was shown to be 8.1 for the elastomer incorporated with 10 phr LMS-EIL, indicating excellent potential for use as an actuator.