Adhesives Inspired by Marine Organisms: Multifunctional Design and Application for Complex Wet/Underwater Environments

Achieving strong adhesion in humid or underwater environments is a long-term challenge in materials science. Water molecules form a hydration layer on the substrate surface, blocking effective contact between the adhesive and the interface, leading to the failure of traditional adhesives. The wet adhesion strength of viscoelastic materials is due to the synergistic effect of interfacial chemical bonds and multiscale energy dissipation, but water environment can seriously interfere with this mechanism. In nature, mussels, barnacles, and sandcastle worms have evolved unique wet adhesion strategies: mussels achieve interfacial bonding through metal coordination and oxidative cross-linking of catechol groups; barnacle adopts a completely different “phase separation solidification” pathway, in which its gelatinous protein complex undergoes liquid–liquid phase separation to form a dilution-resistant coacervate that spreads with extremely low surface tension and displaces the interfacial hydration layer. Sandcastle worms use polyelectrolyte composite coagulation to bond mineral particles. Inspired by this, the synthetic pathways of biomimetic wet adhesives include the synthesis of peptides, modified polymers, and polydopamine systems, which have shown promising applications in wearable electronic devices, marine engineering restoration, and biomedical fields. This article systematically reviews the progress of biomimetic materials, providing reference for the rational design of high-performance adhesive materials.