Designing protein-tannin nanohesives for rapid, universal, and robust wet-adhesion with on-demand debonding

Establishing the adhesion between soft yet wet materials remains challenging due to the interfacial water, the dilution of polymer strands, and the lubrication of the interface. Herein, nanohesives based on the grape seed protein and tannic acid (GSP-TANHs) were reported to adhere various hydrogels (including polyvinyl alcohol, polyacrylamide, poly 2-acrylamido-2-methyl-1-propane-sulfonic acid, and chitosan) with each other. Due to the rapid formation of widely available short-range forces between nanoparticles and hydrogel surfaces, GSP-TANHs could establish the initial adhesion around 10 s. Additionally, they served as universal hesives to a wide range of substrates without chemical modifications or pretreatments for adherents, such as plastics, cardboard, glass, iron, and rubber. The adhesion force for cardboard reached 11.37 N. Meanwhile, the adhesion force could be easily regulated by varying nanoparticle sizes and specific surface area. Thanks to the sensitivity of hydrogen bonding to heating, on-demand debonding was realized after increasing the temperature to 45 °C. Because of the reversible interactions, the adhesion was also repeatable. Due to the merits of grape seed protein and plant polyphenol, it could be completely biodegraded within 7 days. Bearing several merits, this strategy has promising applications in new implantable devices, E-skin, and biofabrication processes.