Self-Healing Dielectric Elastomers for Damage-Tolerant Actuation and Energy Harvesting

Abstract

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 min, methyl-3-mercaptopropionate (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 εr = 7.5 and a low tan δ = 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 an 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.

Siloxane Matrix Molecular Weight Influences the Properties of Nanocomposites Based on Metal Complexes and Dielectric Elastomer

“…Over the last three decades, there has been an increased focus on the development of materials that can work as actuators or energy harvesting devices [ 1 , 2 ]. In these applications, mechanical energy from kinetic processes such as human walking, wind, or sea waves is converted to direct electrical current.…”

Challenges and Opportunities of Self‐Healing Polymers and Devices for Extreme and Hostile Environments

“…The team also reported methyl‐3‐mercaptopropionate grafted SBS (M3M‐SBS) for dielectric actuation, which actuated with 9.2% radial strain under an electric field of 39.5 MV m –1 and exhibited an energy density of up to 11 mJ g −1 during energy harvesting. [ 121,122 ]…”

Dynamic Polymer Networks: A New Avenue towards Sustainable and Advanced Soft Machines

“… Graphs showing relationships between a) dielectric breakdown strength ( E b and relative permittivity ( ϵ r ); b) stiffness and strain at break; c) energy density and actuation strain; and d) figure of merit for energy harvesting and figure of merit for actuation for SBS‐based elastomers (circles), silicone‐based elastomers (squares), and acrylic‐based elastomers (triangles). The data for each of the materials were taken from: NH 2 /COOH‐silicone, [21] SBS, [20b] silicone, M3M‐SBS, [20c] MG‐SBS, [20b] MG/TG‐SBS, [20a] DA‐acrylic, [22] CN‐silicone, [20e] VHB‐4910, [23] ME‐silicone, [20d] MG‐silicone, [20d] TG‐silicone [20d] …”

“…Self‐healing was induced by a weak electrostatic interaction between the δ +CH and δ − aromatic centres of the grafted esters and styrene rings, respectively. In addition, a recovery in the breakdown strength and actuation performance of up to 86 % was observed for these materials [20b,c] . A hydrogen bonding network that enhanced self‐healing at elevated temperatures was introduced into MG‐SBS via the simultaneous grafting of thioglycolic acid (TG).…”