Inkjet Printing of Complex Soft Machines with Densely Integrated Electrostatic Actuators

A multimaterial inkjet printing method for integrated soft multifunctional machines is reported, combining dense arrays of electrostatic actuators, multilayer electrical routing, and complex networks of microfluidic channels in one printing process. Most additive manufacturing methods for soft robots are developed for devices driven by external fluidic pressure sources and are not suited to fabricate soft electrically driven actuators. To integrate electrostatic zipping actuators and microfluidics in stretchable soft machines without any rigid components, inks for sacrificial layers, dielectric elastomers, and compliant electrodes are developed herein, along with a unified printing process to print multilayer structures. Printed 2.5D stacks are transformed into fully functional 3D soft machines by inflating thin elastomer channels. Two demonstrators are reported, each consisting of seven printed layers: a flexible peristaltic pump and a compliant slug drive, inspired by the locomotion of slugs. The peristaltic pump has six integrated actuators, whereas the slug drive has 28 integrated actuators, generating a travelling wave used to transport objects. These soft devices demonstrate how inkjet printing produces densely packed high‐voltage actuators, including vias for electrical routing. Sensors and logic may be printed in the future to produce more complex autonomous soft machines.