Oxidating liquid metal interface integrated capacitive pressure detection

The characteristics of real-time monitoring and flexible integration based on passive capacitive detection are becoming the preferred sensing strategy for wearable devices. However, the currently designed capacitive sensors mostly focused on the bionic microstructures to improve sensitivity and measurement accuracy, while ignoring the inherent mechanical wear and resistance of multilayer structures. In this paper, an integrated monolithic capacitive pressure detection based on room temperature liquid metal is designed and fabricated, avoiding the tightness problem of the multi-layer structure. The oxidized paste-like liquid metal owning superior interfacial wetting properties can stably adhere to the surface of the porous framework. The gas-filled porous framework endows the capacitive sensor with a mechanical response of 0.0557 g with a response and recovery time of 1.26 and 0.63 s under a load condition of 150 Pa, and steadily maintained in 1600 cycle tests. Finally, the capacitive sensor is employed to detect human physiological signals and force shock responses, which could clearly distinguish different action signals, providing a new platform for the subsequent development and design of integrated capacitive sensors.