Bamboo-Derived Maleated Lignin-Containing Cellulose Nanofibers for Tough and Conductive Hydrogels

Abstract Lignin-containing cellulose nanofibers (LCNFs) offer a sustainable alternative to fully delignified nanocellulose by preserving native lignin while reducing chemical and energy consumption. Herein, bamboo-derived LCNFs were prepared through a one-step maleic anhydride esterification without toxic solvents or catalysts. The resulting LCNFs exhibit high lignin content (27.14%), abundant surface carboxyl groups (1.85 mmol g−1), ultrafine diameters (∼2.67 nm), and high aspect ratios (>1 μm), enabling excellent dispersion and strong interfacial interactions with polymer networks. When incorporated into poly(acrylamide-co-lauryl methacrylate) hydrogels, the LCNFs function as dual-functional crosslinkers by simultaneously providing covalent anchoring sites and physical entanglement points. The synergistic interactions significantly enhance the mechanical robustness and electrical performance of the hydrogels, yielding a tensile strength of 1.12 MPa, elongation at break of 1545%, toughness of 7.33 MJ·m−3, and electrical conductivity of 1.15 S/m. Multiscale analyses reveal that the reinforcement originates from cooperative hydrogen bonding, covalent coupling, and nanoscale network interpenetration induced by LCNFs. This work demonstrates a green and efficient strategy for converting bamboo biomass into functional LCNFs and highlights their potential as sustainable reinforcing and crosslinking components in high-performance conductive hydrogels for flexible sensing and wearable applications.