Resonant printing flexible piezoresistive pressure sensor with spherical microstructures

Flexible pressure sensors have attracted much attention in academia owing to their wide-ranging applications in wearable electronics, medical electronics and digital health. However, practical engineering applications have been restricted because of limitations in efficiency, manufacturing costs and sensitivity. In this work, we propose an innovative method for high-efficiency printing of microstructures that replaces traditional inverted mold methods. We developed a high-sensitivity flexible piezoresistive pressure (FPP) sensor with a high manufacturing efficiency and low manufacturing cost. The sensor was encapsulated by connecting a polydimethylsiloxane film with microstructures prepared using the sandpaper-molding method, and then integrated with an interdigital electrode and spherical micro-structures fabricated via resonant printing. In this way, the manufacturing process was simplified by breaking it down into two steps. The performance of the sensor was assessed by conducting experiments under different pressure regimes. The results demonstrated ultra-high sensitivity (0.0058-0.024 kPa(-1)) and a wide pressure detection range (1-100 kPa), spanning the entire range of pressure monitoring typically observed for vital and health signals. The response time of the sensor was less than 72 ms. Furthermore, the performance of the fabricated sensor was highly stable after 1000 bending cycle. The potential applications of the FPP sensor are discussed in area such as the human body and mouse.