Jun Hu, Xiao-Ping Zhou
Liquid metal-based flexible sensors have wide applications in wearable devices, motion monitoring, and other fields. These sensors consist of liquid metals for sensing and flexible substrates for stretching. Due to the poor interfacial adhesion between liquid metal and flexible substrates, complex manufacturing processes are typically required to encapsulate the liquid metal within the substrates. In this paper, we demonstrate a manufacturing process for flexible sensors, which aims to print MXene-bacterial cellulose gels (MXene-BC) and liquid metals (LM) onto flexible substrates, thereby forming a conductive layer with sensing capabilities. The liquid metal forms stable conductive sensing regions on the thermoplastic polyurethane substrate via a silicone brush printing method. The developed MXene/liquid metal sensor exhibits a large measurement range (>250% strain), a high gauge factor of 1.95, cyclic stability (5000 cycles), rapid response/recovery time (24 ms/26 ms), and temperature stability (10 °C–40 °C). The sensor can be directly attached to the skin to accurately monitor joint bending and body movements, demonstrating significant potential for human motion detection applications.