High-Fidelity Conformal Printing of 3D Liquid Alloy Circuits for Soft Electronics.

Owing to the great deformability from fluid, liquid alloy-based soft electronics has inherent advantages over rigid-based ones for applications such as stretchable intelligence or soft robotics, where high fidelity of three-dimensional (3D) conformability or dynamic morphology is required. However, current fabrications heavily rely on planar techniques, which severely limit their great potential in such attracting applications. By tuning the wettability of liquid alloy on a soft substrate through a selective surface morphology modification, we present a flexography printing technique of liquid alloy circuits on both planar (from diverse materials) and 3D complex surfaces and investigate the tuning mechanism and the relation between liquid alloy wettability and surface morphology modification. In a demonstration, high-fidelity printing of liquid alloy circuits can be deployed not only on the outline but also on small pits of strawberry surface, and the circuits work well in a dynamic deformation. Furthermore, being compatible with current industry process, our technique can be highly potential for future mass manufacturing of liquid alloy-based soft electronics.