Three-Dimensional Coprinting of Liquid Metals for Directly Fabricating Stretchable Electronics

It is a significant challenge to fabricate functional stretchable electronics by directly printing Ga-based liquid metals (GLMs) due to their high surface tension. In this study, a coprinting method is developed, in which GLMs are printed together with elastic materials to overcome their poor printability. The continuous contact and extrusion of the external highly viscous elastic materials with its internal liquid metal inhibits the balling of liquid metal, achieving the liquid metal three-dimensional (3D) printing successfully. A multifunctional stretchable inductance sensor was 3D printed at the first time. This sensor can be used to test axial stretch, deflection, and radial stretch, allowing tracking of the status of soft snake structures such as the end executor of endoscope and fingers.