Self-healing dielectric elastomers for damage tolerant actuation and energy harvesting.

The actuation and energy harvesting performance of dielectric elastomers are strongly related to their intrinsic electrical and mechanical properties. For future resilient smart transducers, a fast actuation response, efficient energy harvesting performance and mechanical robustness are key requirements. In this work, we demonstrate that poly (styrene-butadiene-styrene) (SBS) can be converted into a self-healing dielectric elastomer with high permittivity and low dielectric loss which can be deformed to large mechanical strains; these are key requirements for actuation and energy harvesting applications. Using a one-step click reaction at room temperature for 20 mins, methyl-3-mercaptoproionate (M3M) was grafted to SBS and reached 95.2% of grafting ratios. The resultant M3M-SBS can be deformed to a high mechanical strain of 1000%, with a relative permittivity of r = 7.5 and a low tan  = 0.03. When used in a dielectric actuator it can provide 9.2% strain at an electric field of 39.5 MV m-1, and can also generate energy density of 11 mJ g-1 from energy harvesting. After being subjected to mechanical damage, the self-healed elastomer can recover 44% of its breakdown strength during energy harvesting. This work demonstrates a facile route to produce self-healing, high permittivity and low dielectric loss elastomers for both actuation and energy harvesting, which is applicable to a wide range of diene elastomer systems.