The soft liquid metal-based pressure sensor based on resistance-capacitance coupling

With the rapid development of the intelligent technology, flexible sensors have widely applied in wearable electronic products, human-computer interaction, soft robots, health care and other emerging fields. At present, mechanical sensors are based on resistance or capacitance changes alone to achieve a perceived response to force. Meanwhile the methods of flexible mechanical sensors to improve the sensitivity are mainly micro-structuring of the electrode or dielectric layer, which is a complicated process and less probing of the electrode shape. Therefore, this paper proposes a flexible sensor based liquid metal to measure mechanics through resistive-capacitive coupling. Through testing, we obtained the optimal preparation scheme. We also explored the mechanical properties of the sensor design with different combinations of liquid metal electrode shapes using simulation, and then tested the mechanical properties of the double helix liquid metal sensor prepared according to the model structure. With resistive-capacitive coupling, the sensor can achieve a sensitivity of 0.4653 ​kPa −1 with a response range of 10∼343 ​Pa, and it has good tensile and compressive response, and cyclic stability. This study provides a new structural design direction for the subsequent application of liquid metal in flexible sensing with high sensitivity. • Preparation of flexible electronic sensors using non-toxic liquid metal. • The sensitivity of the pressure sensors was improved through capacitive-resistive coupling. • Simple patterning of liquid gallium metal and optimized electrode preparation were proposed. • Mechanical properties of different liquid metal electrode shapes ​were ​simulated with simulation software.