Stretchable and Soft Electroadhesion Enhanced By Liquid-Metal Subsurface Microstructures

Electroadhesion is an attractive mechanism for robotic components to electrically modulate adhesion to surfaces for gripping, climbing, and locomotion. Previously, electroadhesion has been implemented on flexible substrates, but not on soft or stretchable substrates that are compatible with, for example, soft robotics or stretchable electronics. Here, electroadhesion was generated and enhanced in a soft and stretchable elastomeric substrate by embedded subsurface liquid metal-filled electrodes. Applying potential between these interdigitated electrodes modulates the adhesion of these devices to surfaces in a reversible manner. In addition to creating sot and stretchable constructs, the use of liquids intrinsically enhances the adhesion by the surface stresses caused by the capillary pressure inside the fluid-filled microchannels. This approach to electroadhesion can be implemented in ultra-stretchable and soft substrates, including those used in robotics, due to the inherently soft and deformable electrical conductivity of the liquid metal electrodes.