Tunable and hierarchically porous self-powered sensor with high sensitivity

The remarkable potential applications of flexible and wearable devices in the fields of motion monitoring and preventative healthcare have garnered considerable attention in recent years. However, it is still an everlasting challenge to construct flexible sensors with high sensitivity over the detection range for smart wearable devices. Herein, a hierarchically porous sensor using self-foaming silicone rubber is designed and fabricated for motion monitoring and disease diagnosis. By adjusting the foaming formulations, the pore size and pore density could be controlled within a single sensor. This hierarchically porous sensor possesses a gradient compression characteristic, resulting in a remarkable sensitivity of 0.2988 kPa−1 in the low-pressure range and a maximum detection pressure of 63.75 kPa. Consequently, it can effectively identify signals from different pressing modes and compression distances. Furthermore, a smart insole is fabricated with a sensor array to provide precise information for motion monitoring and foot disease diagnosis. This work might provide a promising strategy to control foam morphology of pressure sensor, enabling precise pressure perception in the fields of sporting posture assessment, medical diagnosis, and healthcare monitoring.