Red Sea Star-Inspired, Rapid Underwater Self-Healing Polyurethane Based on Dual Hydrophobic Units and Tandem Dynamic Bonds

Red sea stars exhibit an extraordinary underwater self-healing capability driven by fibrinolytic enzyme secretion, enabling survival in challenging marine environments. Inspired by this biological mechanism, we developed a polyurethane (DSFPU-3) capable of rapid underwater self-healing. By integrating dual hydrophobic units (alkyl side chains and fluorine groups) with tandem dynamic bonds (disulfide and imine bonds), DSFPU-3 achieved a water contact angle of 99.3° and maintained stable microphase structures and micromorphology even after 4-day water soaking. The synergistic effect of hydrophobic units and dynamic bonds enabled self-healing at a speed exceeding 33.33 μm/h, achieving 98% efficiency and allowing the material to endure significant mechanical stress post-healing. Small-molecule modeling experiments and rheological analyses validated the bond exchange mechanisms of the tandem dynamic bonds, underscoring their critical role in accelerating the self-healing process. This study presents a novel strategy for fabricating rapid underwater self-healing polyurethanes, representing a significant advancement in their application under aquatic conditions.