A wearable and sensitive carbon black-porous polydimethylsiloxane based pressure sensor for human physiological signals monitoring

Development of flexible, low cost, highly sensitive, and large-area compliance pressure sensors that can detect human physiological signals have become one of the vital component units for wearable electronics. Herein, a highly flexible and stretchable carbon black-porous polydimethylsiloxane-based pressure sensor has been successfully fabricated using a simple and effective fabrication technique with a sacrificial power template method. The pore size on the performance of pressure sensor is systematically investigated using KCl, NaCl, and sugar as powder templates to produce the porous PDMS. Notably, the KCl-templated PDMS pressure sensor exhibits a maximum pressure sensitivity (1.07 kPa(-1) in 0-2 kPa), which is significantly higher than that of the NaCl-templated PDMS pressure sensor (0.86 kPa(-1) in 0-2.5 kPa) and the sugar-templated PDMS pressure sensor (0.40 kPa(-1) in 0-2.8 kPa). The KCl-templated PDMS pressure sensor has other advantages as well, including a fast response time of - 16 ms, a wide sensing range of 0-11,700 Pa, a low detection limit of - 2 mN, and a good reproducibility for over 3000 cycles. With these advantages, it is demonstrated that the pressure sensor can monitor minute mechanical events and human physiological signals, such as weak airflow blown, swallowing motion, finger touch, and pronunciation. Therefore, this new pressure sensor, which exhibit excellent comprehensive performance, will have wide application prospects in health monitoring and wearable devices.