High-Strength, Freeze-Resistant, Recyclable, and Biodegradable Polyvinyl Alcohol/Glycol/Wheat Protein Complex Organohydrogel for Wearable Sensing Devices

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.

Proteins for Applied and Functional Materials

“…show that stable porous foams based on gluten protein derived from starch production can be manufactured using pilot-scale extrusion . Highly porous protein-based materials and hydrogels are also reported here by the work of Li et al, where PVA, glycol and wheat protein were combined, forming functional structures with advanced properties relevant to the area of biosensors, resisting loads even 6000 times higher than its own weight . The potential of upcycling natural waste into functional materials is further demonstrated here by the work led by Yazawa et al.…”

“…16 Highly porous protein-based materials and hydrogels are also reported here by the work of Li et al, where PVA, glycol and wheat protein were combined, forming functional structures with advanced properties relevant to the area of biosensors, resisting loads even 6000 times higher than its own weight. 17 The potential of upcycling natural waste into functional materials is further demonstrated here by the work led by Yazawa et al This group in Japan has demonstrated that cocoon waste as a protein source can be upcycled into silk fibers solely by using aqueous solutions and dry-spinning processes. 18 Exploiting Proteins as the Next Generation of Functional Materials.…”

Degradable and Recyclable Hydrogels for Sustainable Bioelectronics

“…In addition to the above-reported natural polymers, there are plenty of other natural polymers with unique properties that are currently less developed but have the potential to be utilized in the future for the fabrication of the next generation of degradable bioelectronics. − Collagen, the most abundant extracellular matrix protein, is derived from animal tissues . In terms of spatial structure, collagen shows a special three-stranded helical winding structure with high mechanical strength.…”