An Underwater\nSelf-Healing Polysulfide Elastomer with\nIn-Situ Curing and Adhesion

As oceanic activities expand, the strategic importance\nof designing\nmultifunctional materials suitable for underwater applications becomes\nincreasingly apparent. Underwater self-healing materials offer significant\nadvantages by autonomously repairing damage in-situ during operations,\nthereby minimizing resource waste and enhancing environmental sustainability.\nHowever, most self-healing materials do not have sufficient stability\nin aquatic environments due to the presence of water-sensitive weak\ncross-linking bonds. Herein, polysulfide elastomers capable of underwater\nself-healing have been developed through a straightforward, one-step\nthiol–ene click reaction strategy. This reaction can occur\nin-situ underwater due to its water insensitivity. The abundance of\ndisulfide bonds in the elastomer enables the formation of coordination\nbonds with metals, endowing the material with outstanding underwater\nmetal adhesion properties. The optimal elastomer LPTM-55 shows extraordinary\ntoughness of 1.49 MJ/m<sup>3</sup>, underwater self-healing efficiency\nof 90% within 7 h and adhesion strength up to 1.2 MPa. This innovative\nmaterial, characterized by its underwater curing, adhesion and self-healing\ncapabilities, demonstrates significant potential for applications\nin underwater sealing and repair.