Ni-GaIn Amalgams Enabled Rapid and Customizable Fabrication of Wearable and Wireless Healthcare Electronics

Recent advances in functional low-melting liquid metals (LMs) provide routes to quickly fabricate wearable devices, which can offer excellent mechanical compliance on human skin compared to conventional rigid wafer-based electronics. Particularly, the Gallium-based LM mixtures are promising materials for use as stretchable and flexible circuits in wearable healthcare electronics due to their fantastic electrical conductivity, favorable fluidity, super compliance, and benign biocompatibility. Here, the authors develop a kind of directly-printed Ni-GaIn functional amalgams, which can efficiently construct wearable healthcare monitors. Unlike EGaIn, Ni-GaIn amalgam owns a tunable and enhanced adhesion, which makes it easy to directly paint on various substrate for customized circuits. A wireless power transfer coil printed with these amalgams is presented to demonstrate the electrical stability under different tensile states. Finally, the authors design a wearable healthcare monitor for pulse wave measurement via collecting pulse wave signals from the wrist steadily. With the advantages of stretchability and rapid manufacture, the functional Ni-GaIn amalgams as currently presented shows a promising approach for individualized wearable electronics.