Versatile underwater adhesive with microarchitecture triggered by solvent exchange

Abstract

Polyelectrolyte complexation is critical to the formation and properties of many biological and polymeric materials, and is typically initiated by aqueous solution mixing that results in fluid-fluid phase separation, e.g., coacervation. Here we report a versatile and strong wet-contact adhesive inspired by sandcastle worm cement that enables both a triggered complexation of polyelectrolytes, and formation of a porous architecture. A catecholfunctionalized weak poly-anion was premixed with a poly-cation in dimethyl sulfoxide (DMSO). The polymer solution was applied underwater to substrates where electrostatic complexation, phase inversion, and rapid setting were actuated by water-DMSO solvent exchange. This process offers enhanced spatial and temporal control of complexation, thereby fostering rapid (≥ 25 s) and robust underwater adhesion (Wad ≥ 2 J/m2) of complexed catecholic polyelectrolytes to all tested surfaces including plastics, glasses, metals, and biological surfaces. The solvent exchange process is adaptable to diverse materials chemistry, supporting functionalities well beyond aqueous complex coacervates.