Lignin/Glycerol-Induced Self-Assembly for Fabricating Tough Poly(vinyl Alcohol)/Liquid Metal Hydrogels in Sensing

Abstract

Hydrogels have been widely used in tissue engineering, soft robotics, and wearable electronics. However, developing hydrogels that simultaneously possess high strength, high stretchability, and good conductivity to meet diverse application requirements remains a significant challenge. In this study, a strategy involving glycerol substitution, liquid metal (LM) coordination, and sodium lignosulfonate (LS) immersion was proposed to enhance the polymer network by adjusting the molecular arrangement and coordination of poly(vinyl alcohol) (PVA), thereby enabling the preparation of high-performance PVA/LM5.0@LS24 hydrogels. The PVA/LM5.0@LS24 hydrogels exhibited a tensile strength of up to 10.7 MPa and a high fracture strain of 833.1%. Additionally, the Young’s modulus and toughness reached 186.4 MPa and 69.9 MJ/m3, respectively. The outstanding mechanical properties demonstrated clear advantages compared to those of other tough hydrogels. Moreover, the incorporation of LM combined with LS immersion endowed the PVA/LM5.0@LS24 hydrogels with excellent electrical conductivity (6.20 S/m). Interestingly, the hydrogel also demonstrated good biocompatibility and excellent coagulation properties, making it suitable for human-sensing applications. The effective method for fabricating highly tough, fatigue-resistant, and stretchable hydrogels shows promising potential for use in artificial ligaments and sensing technologies.