Beetle wing-inspired bio-adhesives with multifunctional nanoarmor: Enhanced performance, biodegradability and environmental safety

The development of sustainable adhesives that reconcile mechanical robustness, environmental resilience, and multifunctionality remains a formidable challenge. Inspired by the passive unfolding-retraction mechanism and hierarchical micro-nano textures of beetle wings, where rigid elytra provide structural support and flexible hindwings enable energy dissipation, we report a fully bio-based adhesive system that integrates rigid-flexible synergy with multifunctional nanoarmor for sustainable adhesion. Lignin was covalently grafted onto natural rubber latex (NRL) via ammonium persulfate-initiated radical polymerization (NRL- g -Lignin), constructing a three-dimensional “rigid skeleton-flexible matrix” network. The resulting NRL- g -Lignin adhesive exhibits a 40.7 % increase in shear strength (0.878 MPa vs. 0.624 MPa) and a significant thermal stability enhancement (T max  = 392.2 °C). Furthermore, the incorporation of cinnamaldehyde-tannic acid nanoemulsions (CA/TA NEs) introduces a homogeneous nanoarmor that improves interfacial adhesion, crack deflection, and offers up to 98.8 % antioxidant (ABTS) and > 99 % antimicrobial efficacy. The adhesive maintains outstanding performance across −18 °C to 100 °C, exhibits excellent substrate compatibility, can be reprocessed via hot-pressing, and demonstrates a 31.4–50.6 % mass loss after 60 days of soil burial, evidencing its biodegradability and reduced persistence. This multiscale, sustainable design paradigm opens new avenues for high-performance adhesives in recyclable composites, biomedical interfaces, and eco-friendly packaging.