Multi-Modal Cyclic Service Dielectric Actuators Enabled by Dynamic Poly(Lipoic Acid)

Conventional dielectric elastomers (DEs) require high operating voltages and pre-stretch to achieve sufficient deformation and hence meet the increasingly demanding actuation requirements, while their irreversible covalent network precludes repair or reprocessing of the system once damage. Herein, a self-healing and reprocessable poly(lipoic acid) (PTA)-based elastomer was developed via inverse vulcanization. Meanwhile, highly insulating deep eutectic solvents (DES) composed of natural carboxylic acids were further incorporated, in which the long aliphatic segments can effectively increase the free volume of the network through plasticizing effect. Therefore, the resulting DEs system exhibits significant decreases in viscous hysteresis and Young's modulus, thereby achieving a ∼92% actuation strain without pre-stretching. Meanwhile, the abundant disulfide moieties of PTA backbone further enable the system with remarkable self-healing capability and thermal-triggered recyclability. Accordingly, both mechanically punctured and electrically broken actuators can restore ∼80% of original electromechanical performance either through bulk reprocessing or localized “resection-patching” suturing of the DEs component. We envision that the present design concept provides new insights for optimizing the intrinsic actuation performance and cyclic serviceability of DEs, which is of significant scientific and practical values.