PVA-based hydrogen-bonded supramolecular adhesive with core–shell nanoarchitectures for multifunctional and sustainable applications

INTRODUCTION: Sustainable, high-performance adhesives are in high demand, yet their development is hindered by the trade-off between environmental friendliness and multifunctionality. Poly(vinyl alcohol) (PVA) offers a renewable and non-toxic base, but its intrinsic properties limit performance in demanding applications. OBJECTIVES: This study aims to develop a PVA-based green adhesive with enhanced adhesion strength, durability, and multifunctionality, including flame retardancy, antibacterial, and anti-mildew properties, while maintaining environmental compatibility. METHODS: A nano core-shell structure was constructed by integrating tannic acid (TA) and hexa(1,2,4-triazol-3-ylamine) cyclotriphosphazene (HATA) into the PVA matrix. Hierarchical supramolecular hydrogen-bonded networks were formed via multivalent hydrogen bonding interactions and nanoscale confinement effects. Adhesive performance, durability, and multifunctionality were evaluated through mechanical tests, flame-retardant assessments, antibacterial assays, and molecular dynamics simulations combined with spectroscopic characterization. RESULTS: The incorporation of HATA significantly enhanced interfacial adhesion to diverse substrates and enabled excellent reusability, with performance maintained after multiple cycles and prolonged exposure to acidic or basic environments. HATA's phosphazene and triazole groups imparted superior flame retardancy, antibacterial, and anti-mildew properties. Mechanistic studies revealed that HATA reinforced and crosslinked the supramolecular hydrogen-bonding network through its rigid cyclotriphosphazene core and multivalent motifs, promoting nanoscale confinement and cohesive strength. CONCLUSION: This work demonstrates a scalable strategy for constructing sustainable PVA-based adhesives with exceptional multifunctionality and durability. The approach addresses the performance-sustainability trade-off and offers broad potential for advanced industrial applications.