Lignin nanoparticle/MXene-based conductive hydrogel with mechanical robustness and strain-sensitivity property via rapid self-gelation process towards flexible sensor

• Published in: International journal of biological macromolecules 2025-02, Vol.291, p.139086, Article 139086
• Main Authors: Yang, Yu-Qin, Pang, Xiao-Wen, Zeng, Zi-Fan, Xu, Zhi-Chao, Qin, Yu-Qing, Gong, Li-Xiu, Ding, Haichang, Dai, Jinfeng, Li, Shi-Neng
• Format: Article
• Language: English
• Subjects: Conductive hydrogel; Rapid self-gelation; Strain sensor
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.139086

Conductive hydrogels have been showcased with substantial potential for soft wearable devices. However, the tedious preparation process and poor trade-off among overall properties, i.e., mechanical and sensing performance, severely limits flexibility of electronics' applications. Herein, we have developed a rapid self-gelation system for achieving high-performance conductive hydrogel within several minutes at ambient condition. The rapid gelation mechanism is attributed to the hydroxyl radical species generated with the help of lignin nanoparticle-Mn+1 (Ag+, Ca2+, Mg2+, Al3+ and Fe3+) based on reversible redox reaction and MXene activization effect. By adjusting the material components, the cross-linked polymer network can be highly strengthened by multiple physical interactions and nano-reinforcement, strongly supporting the mechanical performance. Comparatively, Fe3+-based conductive hydrogel displays integrated merits of mechanical robustness, high stretchability and good electrical conductivity. Meanwhile, due to excellent mechanical and electrical performance, such hydrogel-based sensor possesses good sensing performance, i.e., high sensitivity (maximum GF: 1.08), cyclic reliability and wide work window (0–860 %), displaying promising application in strain-induced detection. Our sensors also produce stable and reliable signal output for signature/vocal recognition. Apparently, the strategy developed herein sets up an innovative concept for highly-efficient green fabricating advanced hydrogel materials for emerging wearable electronics. •The multifunctional hydrogel can be achieved within a scale of hundred seconds at ambient condition with no energy supply.•The hydrogel exhibits a well trade-off among the integrated properties, i.e., mechanical robustness and high conductivity.•The synergy of multiple physical interactions and nano-reinforcement contributes to intriguing overall properties.•A hydrogel-based sensor displays a good sensing applicability response to variational deformation conditions.