Multi-Level Pyramidal Microstructure-Based Pressure Sensors with High Sensitivity and Wide Linear Range for Healthcare Monitoring

Abstract

Flexible pressure sensors have garnered significant attention in the field of wearable healthcare due to their scalability and shape variability. However, a crucial challenge in their practical application for various healthcare scenarios is striking a balance between the sensitivity and sensing range. This limitation arises from the reduced compressibility of the microstructures on the surface of pressure-sensitive materials under high pressure, resulting in progressive saturation of the sensor's response and leading to a restricted and nonlinear pressure sensing range. In this study, we present a novel approach utilizing multi-level pyramidal microstructures in flexible pressure sensors to achieve both high sensitivity (8775 kPa −1 ) and linear response (R 2 = 0.997) over a wide pressure range (up to 1000 kPa). The effectiveness of the proposed design stems from the compensatory behavior of the lower pyramidal microstructures, which counteracts the declining sensitivity associated with the gradual hardening of the higher pyramidal microstructures. Furthermore, the sensor demonstrates a fast response time of 11.6 ms and a fast relaxation time of 3.8 ms and can reliably detect pressures as low as 30.2 Pa. Our findings highlight the applicability of this flexible pressure sensor in diverse human body health detection tasks, ranging from weak pulses to finger flexion and plantar pressure distribution. Notably, the proposed sensor design eliminates the need for replacing flexible pressure sensors with varying ranges, thereby enhancing their practical utility.

Unlocking the Potential of Wearable Sensors in Healthcare and Beyond

“…While the sensors themselves do not necessarily need to be novel, innovation in sensor design, utility, or implementation needs to be clearly articulated. Some examples of recent innovation in physical sensors include the rapid self-healing hydrogel that maintains ultralow electrical hysteresis, microstructured pressure sensors that show high sensitivity to foot posture, and thermoelectric hydrogel-based electronic skin for sensing temperature, pulse rate, and sweat content . We anticipate that innovation in the device form factor coupled with meaningful applications of physical sensors will contribute to opportunities of physical sensors to advance healthcare, enhance training of athletes, improve physical therapy, and ease rehabilitation.…”