Bioinspired micro/nanofibers interlocking for high-strength self-bonded bamboo material

The key challenge in developing sustainable lignocellulosic materials lies in the simultaneous enhancement of mechanical performance and environmental friendliness without synthetic adhesives. Herein, inspired by the microstructure of bee tarsal setae, we propose a novel strategy integrating in-situ nanofiber liberation with lignin retention as a biomacromolecule binder to fabricate self-bonded bamboo fiber material (S-BFM). Unlike conventional delignification approaches, our method preserves native lignin, which undergoes hydrothermal softening during hot pressing to reinforce inter-fiber bonding, while water-induced swelling promotes robust micro/nanofiber interlocking. Molecular dynamics simulations revealed that retained lignin strengthened intermolecular interactions. The S-BFM achieved excellent mechanical strength of 59.4 MPa, exhibiting a 748.6% increase compared to untreated controls. Furthermore, after silane coupling modification, the material exhibited exceptional dimensional stability with a thickness swelling of only 7.3% (24 h), far superior to unmodified S-BFM (55.4%). The material also demonstrated high thermal stability (decomposition temperature up to 376.9 °C) and a favorable life-cycle environmental profile. This bioinspired design resolves the long-standing trade-off between mechanical robustness and ecological sustainability, offering a promising alternative to conventional plastics for high-performance applications such as smart card substrates.