Dielectric Elastomer Reconciling Electromechanical Responsiveness and Viscoelastic Dissipation for Crawling Robots

Dielectric elastomer actuators (DEAs) are well-suited for soft robotics due to their deformation. However, the low dielectric constant and high elastic modulus of conventional DEs constrain actuation strain. In this work, a polar monomer was incorporated into acrylic elastomer to enhance dielectric properties, while the addition of flexible long-chain cross-linkers forms a flexible network, facilitating dipole orientation and regulating the cross-linking degree to reduce molecular chain interactions. As a result, the acrylic elastomer has three times the dielectric constant (17.4 at 1 kHz) and half the elastic modulus (0.06 MPa) of conventional acrylates. The synthesized DE achieves 311% area strain at 50 MV/m, 6-fold that of VHB elastomers, at a significantly lower actuation electric field. Additionally, it demonstrated a specific energy of 31 J/kg and a specific power of 205 W/kg at a rate of 30 MV/m. The incorporation of a cross-linked network effectively mitigated the viscoelastic effects of acrylate elastomers, ensuring strain stability over at least 4,800 actuation cycles. Furthermore, when employed as an artificial muscle, the DE successfully lifted a 65 g weight while maintaining displacement stability for over 1200 actuation cycles. This work introduced a novel approach along with new design principles for the molecular engineering of fine DEA fine structures.