Robust underwater adhesion is challenging because a hydration layer impedes the interaction between substrates and adhesives. Phenolic adhesives inspired by marine creatures such as mussels were extensively studied, but these adhesives have not reached the adhesion strength and substrate diversity of Man-made dry adhesives. Here, we report a class of ultrastrong underwater adhesives with molecular phenolic designs extending beyond what nature has produced. These non-canonical phenolic polymers show versatile adhesion on various materials, with adhesion strengths exceeding 10 MPa on metal. Incorporating even just a small amount (<10%) of non-canonical phenolic groups into a polymer is sufficient for dramatically enhancing underwater adhesion, suggesting that this new class of phenolic materials will be incorporated into various industrial polymer systems in the future.

Low-fouling phospholipid polymer was conjugated with bio-inspired tethering groups. Immobilization efficiencies of these polymers onto various surfaces were investigated.

No abstract

A gallol-functionalized polymer showed strong adhesion ability underwater. The effect of molecular weight and gallol content have been optimized resulting in the underwater adhesion strength as high as 4 MPa.