Electric‐Thermal Dual‐Responsive HASEL Actuator for Solid–Liquid Bi‐Stabilized Smart Switching

Abstract Hydraulically amplified self‐healing electrostatic (HASEL) actuators generally consisting of dielectric elastomer (DE) and transformer oil have garnered interest in the realm of soft actuators. However, existing DE can hardly reconcile contradictions between high dielectric constants and low modulus, while traditional transformer oil demands a continuous power supply to sustain strain. Herein, by incorporating liquid metal (LM) featuring high dielectric constant and low modulus, with poly(ε‐caprolactone) (PCL) bearing low phase change temperature, a new concept of electric‐thermal dual‐responsive HASEL actuator is first proposed for solid–liquid bi‐stabilized smart switching. It is not only able to simultaneously deliver a tripled dielectric constant of DE from 3.1 to 9.7 (at 1 kHz) and a low modulus (0.12–0.15 MPa), thus achieving a strain of 9% and a specific power of 64.8 W kg −1 ; but also, PCL replaces the transformer oil, acting as a “temperature switch” for the HASEL actuator, i.e., when PCL solidifies, the HASEL actuator stabilizes the deformation, allowing it to continue working even without power supply. Exemplified by valve, the as‐prepared dual‐responsive HASEL actuator can independently control the flow rate of each valve unit. This electric‐thermal dual‐responsive HASEL actuator introduces an innovative strategy for developing the next generation of multifunctional smart switching.