High-Fidelity Fabrication of 3D Multiscale-Structured Pressure Sensors for High-Performance Wearable Sensing.

Abstract

Constructing multiscale structures has been regarded as a promising strategy to improve the overall performance of flexible pressure sensors. However, their manufacturing approach remains a challenge due to the lack of mild, compatible, and scalable processing methods. In this work, a high-precision and controllable fabrication strategy based on a novel secondary replica molding approach is proposed. A paraffin intermediate mold is introduced to reduce potential damage to functional sensing materials, which enables the precise construction of arbitrary structures. The resulting multiscale-structured octet-truss piezoresistive pressure sensor (MSPS-O) exhibits exceptional batch-to-batch reproducibility with a deviation of volume-normalized initial resistance <2.5%. Notably, the sensor delivers a favorable balance between sensitivity and detection range, demonstrating a high sensitivity of 0.219 kPa-1 and a wide detection range of up to 809 kPa. It also exhibits remarkable long-term cyclic stability over 15 000 loading cycles with less than 4% deviation. Furthermore, MSPS-O can be utilized for real-time monitoring of human motion, and can accurately distinguish different gait patterns through machine learning algorithms. This work offers a new approach for the reliable manufacturing technology of multiscale-structured flexible sensors with high stability and consistency.