Graphical AbstractVerifiedA Hetero-Cross-Linking Strategy for Versatile Artificial Muscles with Superior Electromechanical Sensitivity
Dielectric elastomer actuators (DEAs) are promising artificial muscle technologies due to their large actuation strains, high energy density, and fast response. However, their practical application is hindered by a trade-off between increasing the relative dielectric constant (εr) and decreasing the Young's modulus (Y), which limits electromechanical sensitivity (εr/Y) to below 110 MPa⁻¹. Here, we report a hetero-cross-linking strategy to fabricate a semiseparated biphasic bicontinuous dielectric elastomer (SBE) using two commercial silicone elastomers: Elastosil P7676 (mechanical phase, M-phase) and Sylgard 170 (dielectric phase, D-phase). The M-phase provides an ultralow Young's modulus (~10 kPa), while the D-phase offers a high dielectric constant (3.6). With only 10% D-phase content (SBE-1), the material achieves a record-high electromechanical sensitivity of 360 MPa⁻¹. Under an electric field of 35 V μm⁻¹ without prestretching, SBE-1 exhibits a 90% area strain, significantly outperforming pure phases and previously reported DEAs. The interpenetrating phase structure also enhances breakdown strength. SBE-based artificial muscles demonstrate large displacement at high frequencies, achieving a power density of 2250 W kg⁻¹ at resonance (>200 Hz), surpassing natural muscle and prior DEA artificial muscles. A human-like robotic arm with one rotational joint and four pure-shear SBE-based artificial muscles was developed, capable of extending and bending actions. This work provides a versatile strategy for high-performance DEAs, advancing soft robotics applications.
