posted on 2024-01-24, 23:15authored byTongge An, Yongjun Zhang, Jiahong Wen, Zhichao Dong, Qifeng Du, Long Liu, Yaxin Wang, Guozhong Xing, Xiaoyu Zhao
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 (R2 = 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.