Suspension printing of liquid metal in yield-stress fluid for resilient 3D constructs with electromagnetic functions

Abstract

Liquid metal is an ideal conductive material for soft electronics because of its high conductivity and fluidity at room temperature. However, the large surface tension and high mass density of liquid metal make forming three-dimensional (3D) dangling structures a challenging task. Reported here is a suspension printing strategy for direct deposition of galinstan-based liquid metal into 3D dangling structures with high shape fidelity and spatial resolution (~150 μm). Acrylamide/nanoclay suspension served as a yield-stress fluid support bath, with selected hydrogen peroxide to immediately oxidize the gallium skin and strengthen the extruded liquid metal, thus continuous liquid metal filaments were deposited successfully. The subsequent photo-curing of acrylamide/nanoclay works as a resilient outer packaging, giving rise to a ~500% tensile deformation for liquid metal-hydrogel composite. This suspension printing strategy should broaden the opportunity of using 3D and functional liquid metal constructs for soft yet resilient electromagnetic devices.