High-performance flexible piezoresistive pressure sensor based on multi-layer interlocking microstructures

Abstract

At present, the challenge of high-performance flexible piezoresistive pressure sensors remains the combination of high sensitivity and a wide monitoring range. The micro-morphological engineering of sensing materials will greatly contribute to the design and development of flexible piezoresistive sensors. Therefore, a flexible piezoresistive sensor based on a multi-layer interlocking “sandwich” structure was developed. The structure is assembled from polydimethylsiloxane (PDMS)/carbon nanotube (CNT) films with microdome arrays and thermoplastic polyurethane (TPU)/Ti₃C₂T_x MXene nanofiber films. The multi-layer interlocking structure not only significantly increases the contact area and sensitivity between layers, but also greatly improves mechanical and electrical stability. The results show that the PDMS/CNT–TPU/MXene pressure sensor has a high sensitivity of 82.17 kPa⁻¹, a wide pressure detection range of 0–25 kPa, an extremely short response and recovery time of 100 ms, and an excellent dynamic cycling stability of more than 2000 cycles. In addition, the sensor has been used to perform comprehensive human motion monitoring, such as joint flexion, gait monitoring, and gesture recognition, demonstrating its potential for applications in health monitoring, wearable devices, and human–computer interaction.