Fabrication of water-resistant and high-temperature-tolerant adhesives through synergistic bionic strategy to achieve balanced adhesion and cohesion.

Despite significant advancements in adhesive technologies, developing materials that simultaneously achieve high bonding strength, superior water resistance, and excellent thermal stability remains a critical challenge. Inspired by the catechol structures in mussel proteins for wet adhesion and the dense hydrogen bond arrays in spider silk for superior toughness, this study develops a novel water- and heat-resistant adhesive by incorporating tannic acid‑copper nanoparticles (TA-Cu NPs) into a supramolecular polyurethane featuring multiple hydrogen bonds. By optimizing the soft segment molecular weight and hard segment pliability, a supramolecular polymer with dense, high-strength hydrogen bond arrays is first synthesized, enabling exceptional mechanical properties. Subsequently, TA-Cu NPs are integrated at varying loadings, with the optimal 1 wt% formulation (TA-Cu@S2000-AD) forming dynamic hydrogen-bonded and covalent crosslinks that enhance both cohesion and interfacial adhesion. The resulting adhesive exhibits a tensile strength of 70.8 MPa and elongation at break of 1460 %. It demonstrates a lap shear strength of 8.65 MPa on steel, retaining 6.38 MPa at 130 °C and showing negligible degradation after 24-h immersion in water, acid, or alkali. Leveraging reversible hydrogen bonds, the adhesive achieves excellent recyclability, preserving 87.4 % of its initial shear strength after five cycles. This bionic design provides a versatile strategy for high-performance, sustainable adhesives in demanding applications.