A Stretch-Insensitive Pressure Sensor Based on Liquid Metal Composite with a Hierarchical Conductive Network

Abstract

With the rapid advancement of soft conductor technology, stretchable pressure sensors have gained increasing attention for their potential applications in sensing physical interactions on curved and deformable surfaces such as the human body and soft robotics. However, their practical implementation remains challenged by the interference of in-plane stretching, which affects the pressure-sensing performance due to changes in the electrical properties of stretchable electrode materials and/or the deformation of sensing structures. Here, we present a liquid metal composite (LMC)-based stretch-insensitive pressure sensor (SIPS), including the LMC electrodes with a hierarchical conductive network assembled by applying an acoustic field to the LMC, and a pyramid dielectric layer with a strain-distribution design. This hybrid design enables the electrode layer to maintain a highly stable resistance, with variations of less than 5% under a stretching strain ranging from 0% to 150%. Additionally, the pyramid LMC dielectric layer experiences only 10% strain when the SIPS is stretched to 100%, ensuring a highly consistent capacitance-pressure response across different stretching states. Furthermore, our SIPS has been attached on deformable human skin and demonstrated capable of accurately monitoring the physiological signals and human-environment interactions.