Semi-Solid Liquid Metal/Ni Ink Printing-Based Flexible Thin-Film Sensors

Liquid metal is a room-temperature liquid conductor, which has nontoxic and highly conductive properties. Flexible sensors made of liquid metal and flexible substrates have been widely used in wearable electronics, biomedicine, and soft robotics. Existing fabrication methods require the liquid metal to be encapsulated in the flexible substrate, which makes the manufacturing process complicated. Printing technology is an efficient manufacturing method that enables quick and efficient production. This article presents a new process for printing liquid metal, which allows the liquid metal to adhere firmly to the flexible substrate, enabling its use for measurement even without encapsulation. The whole printing process is simple and efficient, and the printed product has excellent electrical stability. Moreover, based on liquid metal printing, highly deformable thin-film sensors are produced for strain and pressure measurements. The thin-film sensors developed in this article have the ability to resist bending and torsional interference. The thin film sensor can be used as a strain sensor to measure 100% of the strain, or as a pressure sensor to measure 0.8 MPa of pressure. This study suggests a new and simple way for future widespread manufacturing of liquid metal-based flexible sensors.