All-Printable Liquid Metal Composite Particle Inks Encapsulated with Laponite and PVP

Recently, liquid metal (LM) has emerged as a promising conductive material for next-generation soft and wearable electronics, due to its stretchability, flexibility, and high electrical conductivity. To fully harness this potential, LM electrodes should be coated onto various target substrates using commercial printing techniques. However, printing LM onto flexible substrates for specific purposes is challenging due to the high surface tension, low viscosity, and poor wettability. To resolve these issues, we developed a liquid metal composite particle (LMCP) ink whose viscosity and wettability can be controlled. We believe the LMCP ink can be used in various commercial printing techniques. This LMCP ink features attributes such as coffee-ring-less, crack-less, bilayer-free, and post-processing-less, achieved solely through simple evaporation, while preserving inherent electrical performance. Key strategies include (i) natural sedimentation of LM particles by gravity, (ii) solvent-trapping effect by Laponite during the sedimentation process, and (iii) Marangoni-driven mixing and subsequent sedimentation of LM particles upon evaporation, and (iv) co-assembly of Laponite and PVP on LM particle surfaces, forming LMCP. The resulting LMCP electrodes showed ultra-stretchability (>1200% strain) on diverse substrates and the capability to fabricate complex-shaped patterns through large-area printing methods. Lastly, we will show some useful potential applications during this talk.