Antifouling and anticorrosion function of repeatable self-healing polyurethane composite inspired by the self-healing principle of cartilage tissue

Micro-cracking caused by the impact of gravel in the ocean is an important factor affecting the longevity of the integrated antifouling and anticorrosion coating. Inspired by the animal cartilage tissue, a series of polyurethane composite coatings (MPU-FrGO) with repeatable self-healing functions were successfully prepared. MPU-FrGO are endowed with excellent antifouling and anticorrosion ability because they contain functional reduced graphene oxide (FrGO) and 2-methyl 4-isothiazoline 3-ketone (MIT). As animal cartilage tissues, two-dimensional structure of FrGO forms hydrogen bond crosslinking and chemical crosslinking with polyurethane in MPUFrGO. The super strong spatial network endows MPU-FrGO3 (the amount of FrGO added is 1 wt%) with excellent mechanical properties and strong self-healing ability. Its stress (35.6 MPa) and strain (861%) is far more than that of PU-FrGO0 (27.2 MPa and 762%). MPU-FrGO3 showed exceptional self-healing performance, and the self-healing efficiency could reach 91% (91% of initial stress) after 15 min of NIR irradiation; the selfhealing efficiency of five cycles can reach more than 83% (83% of initial stress). The |Z|0.01Hz of MPU-FrGO3 can still maintain 3.34 x 108 omega.cm2 after immersed in 3.5 wt% NaCl for 15 days because of the excellent barrier performance of FrGO. Owing to the excellent antibacterial and anti-algal functions of FrGO and MIT, the antibacterial ability and algae inhibition coverage ability of MPU-FrGO3 were 99.5% and 97.1%, respectively. The work provides a heuristic perspective for the design of polymer materials with anticorrosion, antifouling, and self-healing.