Macroscopic assembly of supramolecular coacervates for underwater adhesion.

Achieving rapid, durable, and recyclable underwater adhesion has long presented significant challenges, complicated by hydration layers, slow curing processes, and environmental concerns linked to traditional adhesives. In this work, we introduce an underwater adhesive based on supramolecular ionic liquids, whose functional performance arises from solvent-exchange-mediated self-assembly. By utilizing the Marangoni effect alongside dynamic non-covalent interactions, such as hydrogen bonding, π-π stacking, and electrostatic interactions, we attain fast underwater adhesion with high strength and long-term stability, while ensuring excellent recyclability. Marangoni flow not only speeds up supramolecular aggregation but also effectively penetrates hydration layers, enabling close contact with submerged substrate surfaces. Spectroscopic and theoretical analyses reveal the development of reversible non-covalent networks and guided molecular rearrangements during solvent exchange. This research combines supramolecular chemistry and macroscopic interfacial science to advance adaptive materials with customizable adhesion capabilities.