Suspension 3D Printing of Liquid Metal into Self-Healing Hydrogel

A new conceptual method termed as suspension 3D printing is demonstrated using self-healing hydrogel support to create macroscopic structures of liquid metal that exhibits properties indicative of a nonprintable object. The relationships between the process parameters, supporting gel concentration, and the deposited microdroplet geometry are clarified. The smaller nozzle inner diameter, lower flow rate, and higher printing speed will lead to a smaller droplets size. The gel concentration plays a significant role on patterning the droplets space. The results presented can be applied to design the target feature and further optimize the input parameters. Besides, this paper also illustrates the capability and potential application of the method in constructing 3D macrostructures and stereo electronic systems using these liquid metal droplets. Based on this strategy, it is possible to print liquid metal into sophisticated multidimensional and shape transformable functional structures ignoring the effects of fluid instability, gravity, and surface tension. Furthermore, this work can help remove the limits of materials and technical barriers to enable a wide variety of materials to be printed into arbitrary shapes. It is expected that further practices of the methodology will facilitate the advancements in multiscale droplets generation, flexible electronics, encapsulation technologies, biology and medicine, etc.