Eco-friendly intrinsic self-healing superhydrophobic polyurea/TiO2 composite coatings for underwater drag reduction and antifouling

With more and more exploration of the marine environment, a series of underwater monitoring equipment such as underwater vehicles are used more widely. Reducing the operation cost of underwater equipment and improving work efficiency have become the focus of attention. Superhydrophobic coatings have excellent applications in drag reduction, antifouling and other fields due to their unique surface wettability. This paper reports a superhydrophobic polyurea/TiO2 composite coating with rapid self-healing ability by simple sprinkling or spraying of modified TiO2 nanoparticles on the brushed polyurea coating. The modified TiO2 nanoparticles were driven to migrate to the surface of the coating by the synergistic self-healing effect of the disulfide and hydrogen bonds inside the polyurea, contributing to restoring the superhydrophobicity. This superhydrophobic polyurea/TiO2 composite coating possesses ~11.28 % drag reduction efficiency after being applied to underwater navigation, and it shows ~11.04 times higher water loading capacity than its weight. Moreover, this coating possesses excellent antifouling properties and chemical durability. This work provides new clues for future applications of drag reduction and pollution prevention of underwater exploration equipment.