Song Lei, Wang Zhenwu, Chen Shengjia, Shen Yi, Yin Jingbo, Wang Rong
Laboratory of Advanced Theranostic Materials and Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Ningbo Cixi Institute of Biomedical Engineering, Ningbo, 315300, P. R. China.
Adv Mater. 2025 Mar;37(9):e2417978. doi: 10.1002/adma.202417978. Epub 2025 Jan 16.
Ionic conductive hydrogels have emerged as an excellent option for constructing dielectric layers of interfacial iontronic sensors. Among these, gradient ionic hydrogels, due to the intrinsic gradient elastic modulus, can achieve a wide range of pressure responses. However, the fabrication of gradient hydrogels with optimal mechanical and sensing properties remains a challenge. In this study, it is discovered first that phytic acid (PA) interacts in remarkably distinct manners (i.e., plasticizing effects and phase separation) with different polymers (i.e., polyacrylamide and polyacrylic acid). This distinctive PA-polymer interacting mechanism is innovatively utilized to construct a modulus gradient ionic hydrogel through a simple precursor solution infiltration approach. The gradient hydrogel-based flexible pressure sensor not only achieves a high sensitivity (9.00 kPa, <15 kPa) and a broad sensing range (from ≈3.7 Pa to 1.2 MPa) simultaneously, but also exhibits superior low pressure sensing performance. It successfully recognizes the subtle pressure due to acoustic waves and airflow, as well as the moderate pressure due to speaking and finger pressing and the high magnitude of plantar pressure. In addition, the gradient hydrogel demonstrates remarkable antibacterial properties and biocompatibility. This functional hydrogel with excellent sensing performance and bioactivity exhibits exceptional potential for wearable sensing applications.
离子导电水凝胶已成为构建界面离子电子传感器介电层的极佳选择。其中，梯度离子水凝胶由于其固有的梯度弹性模量，能够实现广泛的压力响应。然而，制备具有最佳机械性能和传感性能的梯度水凝胶仍然是一项挑战。在本研究中，首先发现植酸（PA）与不同聚合物（即聚丙烯酰胺和聚丙烯酸）以显著不同的方式相互作用（即增塑作用和相分离）。这种独特的PA-聚合物相互作用机制被创新性地用于通过简单的前驱体溶液渗透方法构建模量梯度离子水凝胶。基于梯度水凝胶的柔性压力传感器不仅同时实现了高灵敏度（9.00 kPa，<15 kPa）和宽传感范围（约3.7 Pa至1.2 MPa），还展现出优异的低压传感性能。它成功识别出由声波和气流引起的微小压力，以及由说话、手指按压引起的中等压力和足底压力的高强度。此外，梯度水凝胶还表现出显著的抗菌性能和生物相容性。这种具有优异传感性能和生物活性的功能性水凝胶在可穿戴传感应用中具有巨大潜力。
