Forward Design of Single Ultra-Wide Range and Highly Sensitive Flexible Pressure Sensor for Multi- Physiological-Motion Monitoring.

Abstract

Most human physiological and motion information can be converted into surface vibration signals, which can be monitored through flexible wearable pressure sensors. However, the pressure levels generated by different physiological signals vary widely, ranging from a few Pa to several MPa. The current existing flexible pressure sensors struggle to simultaneously achieve such a wide detection range with high sensitivity. To address this challenge, a forward design method is proposed to realize the ultra-wide range and highly sensitive flexible pressure sensor simultaneous via the synergistic effects of the gradient porous structure, a multi-level pyramid array, and a composite piezoresistive material. The sensitivity is calculated to be 345.8 (0-1 MPa) and 3320.2kPa^-1 (1-2 MPa) after linear fitting. Impressively, the sensitivity increases with the increase of pressure, which is unusual as before. Additionally, the sensor exhibits a high resolution better than 1‰ across the full range, a fast response/recovery time (30/50 ms), and long-term operational stability. Significantly, the sensor demonstrates the non-saturating sensitivity characteristics, overcoming the bottleneck of saturation in flexible pressure sensors under high-pressure conditions, thereby enabling high-precision monitoring of physiological and motion signals across different pressure levels.