Modulating Backing Compliance for Low-Voltage, High-Strength Electroadhesive Gripping

Coplanar electroadhesive (EA) devices present significant advantages for soft robotics and adaptive manipulation; however, achieving high adhesion forces at low operating voltages remains a critical challenge, primarily due to microscale interfacial air gaps that severely attenuate electrostatic attraction. While prior research has predominantly focused on dielectric material selection and electrode geometries, the crucial role of structural compliance, particularly that governed by the backing encapsulation layer, has been largely underestimated. Here, we introduce a flexible tri-layer EA pad incorporating a low-modulus polydimethylsiloxane (PDMS) backing layer. Upon application of an electric field, the induced Maxwell stress triggers localized elastic deformation within the soft backing layer, thereby enabling the ultrathin polyimide (PI) dielectric layer to seamlessly conform to the surface topographies of adherents. This "electro-induced conformal contact" mechanism dramatically reduces interfacial air gaps and shortens the effective electrostatic interaction distance. Under optimized conditions, the EA device achieves a robust 0.2 kPa normal adhesion at an ultralow driving voltage of merely 25 V and 112.7 kPa at 750 V. This work establishes a fundamental paradigm for safe, low-power robotic manipulation.