Bai Ningning, Xu Dandan, Su Zhuang, Li Gangqiang, He Lilong, Chen Yanli, Guo Chengxi, Zhou Linxuan, Qin Xianming, Zhang Ji, Wu Daowei, Wang Weidong
School of Mechano-Electronic Engineering, Xidian University, Xi'an, 710071, P. R. China.
State Key Laboratory of Electromechanical Integrated Manufacturing of High-Performance Electronic Equipment, Xi'an, 710071, P. R. China.
Adv Sci (Weinh). 2025 Jul 14:e07135. doi: 10.1002/advs.202507135.
Flexible piezoresistive sensors that offer both high sensitivity and a broad linear detection range are highly desirable for wearable health monitoring, as they facilitate simplified circuit design and enable accurate detection of subtle physiological signals. However, existing sensors typically encounter an intrinsic trade-off between sensitivity and linearity, primarily due to structural stiffening under increasing pressure. Here, a flexible piezoresistive pressure sensor featuring dual-graded microstructures (DGM) is reported, formed by embedding multi-walled carbon nanotubes (MWCNTs) into a thermoplastic polyurethane matrix. Leveraging the synergistic effects of progressive structural deformation and MWCNTs-induced tunneling conduction, the sensor achieves a high sensitivity of 69.8 kPa⁻¹ and a broad linear sensing range up to 300 kPa (R ≈ 0.998). The sensor also exhibits rapid response-relaxation time (totaling 5 ms), stable high-frequency detection up to 200 Hz, and good stability over 5 000 repeated loading cycles. Demonstrations in physiological monitoring confirm the sensor's capability to precisely capture detailed radial pulse waveforms, respiratory rhythms, and subtle heartbeat-induced vibrations. Both a scalable, cost-effective structural fabrication and good overall sensing performance establish the DGM-based sensor as a promising candidate for advanced wearable healthcare monitoring devices.
对于可穿戴健康监测而言，兼具高灵敏度和宽线性检测范围的柔性压阻式传感器非常理想，因为它们有助于简化电路设计，并能精确检测细微的生理信号。然而，现有传感器通常在灵敏度和线性度之间存在内在权衡，这主要是由于压力增加时结构变硬所致。在此，报道了一种具有双梯度微结构（DGM）的柔性压阻式压力传感器，它是通过将多壁碳纳米管（MWCNT）嵌入热塑性聚氨酯基体中形成的。利用渐进结构变形和MWCNT诱导的隧穿传导的协同效应，该传感器实现了69.8 kPa⁻¹的高灵敏度和高达300 kPa的宽线性传感范围（R≈0.998）。该传感器还具有快速响应-弛豫时间（总计5毫秒）、高达200 Hz的稳定高频检测能力以及在5000次重复加载循环中的良好稳定性。生理监测演示证实了该传感器能够精确捕捉详细的桡动脉脉搏波形、呼吸节律以及由心跳引起的细微振动。可扩展、具有成本效益的结构制造以及良好的整体传感性能，使基于DGM的传感器成为先进可穿戴医疗监测设备的有前途的候选者。
