Liu Jingying, Zhang Xinyi, Cui Ying, Liu Yunlong, Wang Wenjun, Guo Yuxin, Wang Qian, Dong Xiaochen
Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211816, China.
School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China.
ACS Appl Mater Interfaces. 2024 Jan 31;16(4):5208-5216. doi: 10.1021/acsami.3c19136. Epub 2024 Jan 18.
Hydrogels are widely applied in the flexible wearable electronic devices field owing to their skin-like stretchability, superb biocompatibility, and high conductivity retention under mechanical deformations. Nevertheless, hydrogels are prone to freezing at low temperatures and losing water at high temperatures, which seriously limits their practical applications. Herein, a binary solvent system of ionic liquid (1-ethyl-3-methylimidazolium chloride) and water was prepared to endow the ionic hydrogel high ionic conductivity (0.28 S m at 25 °C), high transparency (94.26%), and superior freezing tolerance (-50 °C). The multiple hydrogen bonds formed among polymer chains, water, and ionic liquids significantly improved the mechanical properties of the ionic hydrogel, enabling excellent tensile properties (strain >1800%) and durability (1000 times at 100% strain). Moreover, the ionic hydrogel was further assembled into a dual-response sensor, which exhibited satisfactory sensitivity to both tension (gauge factor = 2.15 at 200% strain) and temperature (temperature coefficient of resistance = -1.845%/°C) and can be applied for human motion and body temperature monitoring. This study provides a versatile method for preparing multifunctional hydrogels with a wide range of applications and lays the groundwork for human movement detection and smart health care.
水凝胶因其类似皮肤的拉伸性、出色的生物相容性以及在机械变形下的高导电性保持率而被广泛应用于柔性可穿戴电子设备领域。然而，水凝胶在低温下容易冻结，在高温下容易失水，这严重限制了它们的实际应用。在此，制备了离子液体（1-乙基-3-甲基咪唑氯盐）和水的二元溶剂体系，以赋予离子水凝胶高离子电导率（25℃时为0.28 S m）、高透明度（94.26%）和优异的抗冻性（-50℃）。聚合物链、水和离子液体之间形成的多重氢键显著改善了离子水凝胶的力学性能，使其具有优异的拉伸性能（应变>1800%）和耐久性（100%应变下1000次）。此外，离子水凝胶进一步组装成双响应传感器，对张力（200%应变下的应变片系数=2.15）和温度（电阻温度系数=-1.845%/℃）均表现出令人满意的灵敏度，可用于人体运动和体温监测。本研究提供了一种制备具有广泛应用的多功能水凝胶的通用方法，为人体运动检测和智能医疗保健奠定了基础。
