Surface-patterned gallol pressure-sensitive adhesives for strong underwater adhesion

In this study, we synthesized a gallol-functionalized PSA and generated micropatterns on its surface to improve its underwater adhesion. Compared to the adhesive-substrate interactions of benzyl and phenol-functionalized PSAs in water, Gallol PSA exhibited greater interactions with the substrate. Furthermore, the micropattern on the PSA surface provided a drainage channel for water during the bonding process so that water is not trapped at the substrate-adhesive interface. Moreover, the drainage channel allows the formation of small and uniform adhesion defects, which minimize the deterioration in adhesion caused by water. And the adhesive manufacturing process is also simple, without any gallol protection and deprotection steps, and can be achieved using the current adhesive industry infrastructure. This facile fabrication strategy and its adhesive properties could promote the commercialization of gallol-functionalized PSAs with underwater adhesion.