Fully Erasable Amphibious Adhesives Derived from Soybean Oil with Record-High Underwater Adhesion Strength

Developing amphibious adhesives that combine high adhesion strength with on-demand erasability in both dry and wet environments remains a significant challenge. In this study, biomass-derived, amphibious, and erasable adhesives are fabricated by grafting 3-aminobenzoic acid and 3-aminobenzeneboronic acid onto epoxidized soybean oil (ESO), yielding ESO-Am adhesives. These adhesives are dynamically cross-linked with boroxines, hydrogen bonds, and hydrogen-bonded hydrophobic nanodomains. ESO-Am adhesives exhibit strong and durable adhesion to a wide range of substrates under dry conditions, with adhesion strengths comparable to those of commercial counterparts. Remarkably, they also demonstrate exceptional underwater adhesion without the need for post-curing, achieving an adhesion strength of 5.2 MPa on iron, surpassing previously reported underwater adhesives. This outstanding performance is attributed to the synergistic effect of dynamic boroxine linkages and hydrogen-bonded hydrophobic nanodomains, which enhance both cohesive strength and interfacial interactions. Importantly, the dynamic cross-links allow for complete and on-demand removal of the adhesive by simple ethanol rinsing. In addition, ESO-Am adhesives are biocompatible, degradable in soil, and reusable, retaining 96% of their original adhesion strength after ten cycles of reuse. The combination of strong amphibious adhesion, full erasability, biodegradability, and reusability makes ESO-Am adhesives highly promising for a wide range of sustainable and advanced applications.