阵列微柱离子薄膜离子电子柔性压力传感器及其可穿戴传感应用

文献信息

中文摘要

柔性压力传感器是可穿戴健康监测系统、软体机器人电子皮肤以及柔性人机交互设备的核心传感元件。得益于界面双电层极化效应，离子电子传感具有远高于传统平行板电容式传感器的压力响应灵敏度，在微弱生理信号检测方面具有独特优势。然而，当前致密离子薄膜介电层在压缩下变形空间有限，低压传感能力较差。主流高精度微柱阵列通过光刻、3D打印和金属蚀刻模具制造，需要昂贵设备和复杂制造工艺，难以实现大面积批量生产。随机磨砂凹凸微结构尺寸无序，导致器件迟滞严重、线性范围窄，无法同时实现超高灵敏度和宽压力检测范围。为解决上述多重瓶颈，本文提出一种低成本树脂模板复制工艺，用于制造具有有序微柱阵列微结构的TPU基离子薄膜介电层。结合喷墨打印银导电PI柔性电极，构建了具有三明治层状结构的离子电子柔性压力传感器。系统开展了微观形貌表征、机电传感性能校准和人体可穿戴应用测试等多维度研究，深入阐明了阵列微柱的协同增强机制。测试结果表明，该传感器的有效压力检测范围为0-1038 kPa，既可容纳脉搏信号等超低压，也可承受关节弯曲等中高压载荷。在0-200 kPa低压范围内灵敏度达到23.27 kPa-1，在200-1038 kPa高压范围内稳定保持在3.52 kPa-1，分段线性拟合相关系数分别为0.93和0.96。器件的响应时间和恢复时间均为40 ms，整个加载-卸载循环的迟滞误差仅为2.62%。经过20,000次连续循环加载-卸载测试后，峰值电容输出仅衰减5.1%，验证了优异的机械抗疲劳性和电学稳定性。多场景应用验证表明，该传感器能够准确捕捉人体生理和运动信号，包括桡动脉脉搏、多音节发声引起的喉部变形以及手指和肘关节的多角度弯曲，适用于家庭健康监测、定量康复训练、柔性触觉交互等场景。整个制造过程无需光刻系统、等离子体蚀刻机和3D打印机等高精度微纳加工设备；仅采用通用化学原料和常规实验室仪器。可重复使用的模板实现了低制造成本和大面积涂覆成型，为高性能离子电子柔性压力传感器的工程实施和产业化提供了一种新型低成本技术方案。

英文摘要

Flexible pressure sensors serve as core sensing components for wearable health monitoring systems, electronic skins for soft robots, and flexible human-machine interaction devices. Benefiting from the interfacial electric double-layer polarization effect, iontronic sensing delivers far higher pressure response sensitivity than conventional parallel-plate capacitive sensors, endowing it with distinctive advantages in the detection of weak physiological signals. Nevertheless, current dense ionic thin-film dielectric layers suffer from limited deformation space under compression and poor low-pressure sensing capability. Mainstream high-precision micropillar arrays are fabricated via photolithography, 3D printing, and metal etching molds, which require costly equipment and complicated fabrication procedures, making large-area mass production unfeasible. Random frosted concave-convex microstructures feature disordered dimensions, leading to severe device hysteresis and narrow linear ranges, which fail to achieve ultrahigh sensitivity alongside a wide pressure detection range simultaneously. To address the aforementioned multiple bottlenecks, this paper proposes a low-cost resin template replication process to fabricate TPU-based ionic thin-film dielectric layers with ordered micropillar array microstructures. Combined with inkjet-printed silver conductive PI flexible electrodes, an iontronic flexible pressure sensor with a sandwich layered structure is constructed. Multi-dimensional investigations including microscopic morphology characterization, electromechanical sensing performance calibration, and human wearable application tests are systematically implemented to thoroughly elucidate the synergistic enhancement mechanism of the arrayed micropillars. Test results demonstrate that the effective pressure detection range of the sensor spans 0-1038 kPa, accommodating ultra-low pressures such as pulse signals as well as medium-to-high-pressure loads including joint bending. The sensitivity reaches 23.27 kPa-1 within the low-pressure range of 0-200 kPa and remains stable at 3.52 kPa-1 in the high-pressure range of 200-1038 kPa, with piecewise linear fitting correlation coefficients of 0.93 and 0.96 respectively. Both the response time and recovery time of the device are 40 ms, and the hysteresis error throughout the loading-unloading cycle is merely 2.62%. After 20,000 consecutive cyclic loading-unloading tests, the peak capacitance output only decays by 5.1%, verifying outstanding mechanical fatigue resistance and electrical stability. Validations in multi-scenario applications prove that the sensor can accurately capture human physiological and motion signals including radial artery pulses, laryngeal deformation induced by multi-syllable vocalization, and multi-angle bending of fingers and elbow joints, suitable for home-based health monitoring, quantitative rehabilitation training, flexible tactile interaction and other scenarios. The entire fabrication process eliminates high-precision micro-nano processing equipment such as photolithography systems, plasma etchers and 3D printers; only general chemical raw materials and conventional laboratory instruments are adopted. The reusable templates enable low manufacturing costs and large-area coating forming, offering a novel low-cost technical solution for the engineering implementation and industrialization of high-performance iontronic flexible pressure sensors.