High-Strength, Freeze-Resistant, Recyclable, and Biodegradable Polyvinyl Alcohol/Glycol/Wheat Protein Complex Organohydrogel for Wearable Sensing Devices
Zhenchun Li, Peng Liu, Shaowei Chen, Shiyuan Liu, Yunwu Yu, Wenhao Pan, Tianwei Li, Ning Tang, Yanfeng Fang
Abstract
The application of flexible wearable sensing devices based on conductive hydrogels in human motion signal monitoring has been widely studied. However, conventional conductive hydrogels contain a large amount of water, resulting in poor mechanical properties and limiting their application in harsh environments. Here, a simple one-pot method for preparing conductive hydrogels is proposed, that is, polyvinyl alcohol (PVA), wheat protein (WP), and lithium chloride (LiCl) are dissolved in an ethylene glycol (EG)/water binary solvent. The obtained PVA/EG/WP (PEW) conductive organohydrogel has good mechanical properties, and its tensile strength and elongation at break reach 1.19 MPa and 531%, respectively, which can withstand a load of more than 6000 times its own weight without breaking. The binary solvent system composed of EG/water endows the hydrogel with good frost resistance and water retention. PEW organohydrogel as a wearable strain sensor also has good strain sensitivity (GF = 2.36), which can be used to detect the movement and physiological activity signals in different parts of the human body. In addition, PEW organohydrogels exhibit good degradability, reducing the environmental footprint of the flexible sensors after disposal. This research provides a new and viable way to prepare a new generation of environmentally friendly sensors.