Novel Lignin Hydrogel Sensors with Antiswelling, Antifreezing, and Anticreep Properties

Abstract

Hydrogel shows great potential as a flexible wearable electronic device. However, the practical application of hydrogel is still significantly limited due to the poor functional stability caused by swelling behavior, non-frost resistance caused by high water content, and obvious creep behavior under repeated external force. In this work, macromolecular lignin with a threedimensional network structure, and active functional groups are introduced into the hydrogel through the esterification grafting reaction of methacryloyl chloride. The introduction of lignin effectively improves the antiswelling, antifreezing, and creep resistance of the hydrogel sensor, while maintaining the mechanical properties (elongation at break > 350%, tensile strength > 1.5 MPa) and electrical conductivity (10 S/m). Under extreme environments, the toughness, tensile strength, and elongation at break of the hydrogel remain at more than 96%. Furthermore, the antifreezing, creep resistance, and conductivity of hydrogel sensors are not significantly affected after immersion in water for a long time (72 h). This work proposes a simple strategy to improve the antiswelling, antifreezing, and anticreep properties of hydrogels, which has guiding significance for the preparation of high-performance flexible wearable electronic materials.

Tuning of Chitosan with Lignin derived Bioactive Properties to develop a Lignin Reinforced and Sustainable Food Packaging Biomaterial

“…On the other hand, elongation at the breaking point is indicative of the material’s flexibility and extensibility prior to failure [40]. The incorporation of lignin into hydrogels has been shown to enhance their mechanical properties, with improved stress transfer observed at the interface between the polymer matrix and lignin particles [41]. This phenomenon contributes to the reinforcement of the hydrogel structure, leading to enhanced tensile strength and Young’s modulus.…”

Self-Adhesive, Anti-Freezing Multifunctional Zwitterionic Hydrogels with Lignin-Promoted Rapid Gelation for Flexible Strain Sensors

“…Conventional hydrogels, containing large amounts of water, are prone to freezing in low-temperature environments and drying out at room temperature. This leads to the deterioration of their mechanical properties, , significantly limiting their practical applications. Therefore, this study aims to endow L-Fe@HE-AA/DMAPS hydrogels with antifreezing and antidehydration properties, enabling their long-term use in low-temperature or open environments without compromising mechanical flexibility and self-adhesion.…”

Recent Progress of Anti-Freezing, Anti-Drying, and Anti-Swelling Conductive Hydrogels and Their Applications

“…Additionally, the hydrogel retained 45% of its initial toughness after having been immersed in seawater for one week. Li et al [74] proposed an innovative method to design an ETCH with anti-swelling and anti-freezing properties that involves adding macromolecular lignin to the hydrogel network. Alkali lignin (AL) was modified with methacryloyl chloride through an esterification reaction; the resulting compound was made to interact with vinyl acetate and 1-vinyl-3-butylimidazolium (ionic liquid monomers (ILs)) to form a hydrogel network.…”