Abstract：
Flexible capacitive pressure sensors based on ionic hydrogels (IHs) have garnered significant attention in the field of wearable technology. However, the vulnerability of traditional single-network hydrogels to mechanical damage and the complexity associated with preparing double-network hydrogels present challenges in developing a highly sensitive, easily prepared, and durable IH-based flexible capacitive pressure sensor. This study introduces a novel multicross-linked dual-network IH achieved through the physical and chemical cross-linking of polymers polyvinyl alcohol (PVA) and chitosan (CS), ionic solution H3PO4, and cross-linking agent gum arabic. Flexible capacitive pressure sensors, characterized by high sensitivity and a broad pressure range, are fabricated by employing mesh as templates to design cut-corner cube microstructures with high uniformity and controllability on the IHs. The sensor exhibits high sensitivity across a wide pressure range (0-290 kPa) and with excellent features such as high resolution (∼1.3 Pa), fast response-recovery time (∼11 ms), and repeatable compression stability at 25 kPa (>2000 cycles). The IHs as a dielectric layer demonstrate long-term water retention properties, enabling exposure to air for up to 100 days. Additionally, the developed sensor shows the ability to accurately measure the pulse wave within the small pressure range. By combining the pulse wave acquired by the sensor with a trained neural network model, we achieve successful blood pressure (BP) prediction, meeting the standards set by the Association for the Advancement of Medical Instrumentation and the British Hypertension Society. Ultimately, the sensor proposed in this study holds promising prospects for broad applications in high-precision wearable medical electronic devices.
摘要：
基于离子水凝胶(IHs)的柔性电容式压力传感器在可穿戴技术领域已经引起了极大的关注。然而,传统的单网络水凝胶对机械损伤的脆弱性以及与制备双网络水凝胶相关的复杂性给开发高度敏感的水凝胶带来了挑战，容易准备,耐用的基于IH的柔性电容式压力传感器。本研究介绍了通过聚合物聚乙烯醇（PVA）和壳聚糖（CS）的物理和化学交联实现的新型多交联双网络IH，离子溶液H3PO4和交联剂阿拉伯树胶。柔性电容式压力传感器，具有高灵敏度和宽压力范围，通过使用网格作为模板来设计在IH上具有高均匀性和可控性的切角立方体微结构来制造。该传感器在宽压力范围（0-290kPa）内表现出高灵敏度，并具有出色的功能，如高分辨率（~1.3Pa），快速响应-恢复时间(~11ms)，和可重复的压缩稳定性在25kPa（>2000次循环）。IHs作为介电层表现出长期的保水性能，使暴露在空气中长达100天。此外,所开发的传感器显示了在小压力范围内精确测量脉搏波的能力。通过将传感器采集的脉搏波与训练好的神经网络模型相结合,我们实现了成功的血压（BP）预测，符合医疗器械促进协会和英国高血压协会设定的标准。最终,本研究中提出的传感器在高精度可穿戴医疗电子设备中具有广阔的应用前景。
