Abstract
Liquid metal (LM) is considered one of the most promising conducting materials for soft electronics due to its unique combination of metal-level high conductivity with exceptional deformability and stretchability. However, their practical applicability has thus far been limited due to the challenges of generating chemically and mechanically stable film over a large-area and the need for non-standard fabrication approaches. Here, we report materials and manufacturing methods that enable multiscale patterning (from microns to centimeters) and multilayer integration of ‘solid-state liquid metal (SSLM)’ with the conventional cleanroom process. In this work, solution shearing of a polyelectrolyte-attached LM particle ink is used to generate SSLM films. The stabilized LM particles were observed to form a close-packed thin-film without particle rupture when coated under evaporative regime. This is essential in enabling a subsequent photolithographic lift-off process at wafer-scale to produce high-resolution features (~ 10 µm) of varying thicknesses irrespective of the substrate. Demonstrations of wearable multilayer tactile sensing systems and stretchable skin-interfaced electronics validate the simplicity, versatility, and reliability of this manufacturing strategy, suggesting broad utility in the development of advanced soft electronics.
Photo-patternable, large-area solid-state liquid metal film coated via solution shearing for soft electronics