Liu Cuiwen, Zhang Ru, Wang Yao, Wei Chengmeng, Li Feng, Qing Ning, Tang Liuyan
School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, China.
Mater Horiz. 2023 Aug 29;10(9):3488-3498. doi: 10.1039/d3mh00739a.
In recent years, flexible strain sensors have attracted increasing interest, and accurate sensing and comfortable wearables are highly demanded. However, current flexible strain sensors fail to have wide linearity and high sensitivity simultaneously, and their adhesion is insufficient for convenient wear and precise motion monitoring. Herein, chitosan/poly(vinyl alcohol) hydrogels with phytic acid (PA) and boric acid (BA) as crosslinkers (CS/PVA-PA-BA hydrogels) were fabricated. The synergy of phytic acid and boric acid not only improved the mechanical properties of the obtained hydrogels (1070% of fracture strain and 0.83 MPa of fracture stress), but also provided them with outstandingly strong adhesion. Their adhesive strength was up to 527 kPa for a variety of materials, including glass, silica rubber, steel, polytetrafluoroethylene (PTFE), and skin. In addition, the hydrogel-based strain sensor demonstrated high sensitivity (gauge factor = 4.61), a wide linear strain range (up to 1000%, = 0.996), fast response time (90 ms), and good stability. A flexible strain sensor with such high sensitivity and wide linear range simultaneously, to the best of our knowledge, has never been reported before. The development of CS/PVA-PA-BA hydrogels is expected to inspire a novel method for high-adhesive and high-sensing-performance wearable electronics.
近年来，柔性应变传感器引起了越来越多的关注，人们对精确传感和舒适的可穿戴设备有很高的需求。然而，目前的柔性应变传感器无法同时具备宽线性度和高灵敏度，并且它们的附着力不足以实现便捷佩戴和精确的运动监测。在此，制备了以植酸（PA）和硼酸（BA）作为交联剂的壳聚糖/聚乙烯醇水凝胶（CS/PVA-PA-BA水凝胶）。植酸和硼酸的协同作用不仅改善了所得水凝胶的机械性能（断裂应变达1070%，断裂应力为0.83 MPa），还赋予它们极强的附着力。对于包括玻璃、硅橡胶、钢、聚四氟乙烯（PTFE）和皮肤在内的多种材料，其粘合强度高达527 kPa。此外，基于水凝胶的应变传感器表现出高灵敏度（应变片系数=4.61）、宽线性应变范围（高达1000%，R² = 0.996）、快速响应时间（90 ms）和良好的稳定性。据我们所知，此前从未报道过同时具有如此高灵敏度和宽线性范围的柔性应变传感器。CS/PVA-PA-BA水凝胶的开发有望为高附着力和高传感性能的可穿戴电子产品带来一种新方法。
