Dolphins-inspired antifouling self-healing hydrophilic coatings with hierarchical hydrogen bonds for enhanced durability in antifouling performance based on dynamic poly(urethane-urea)

Hydrophilic coatings are widely used in marine antifouling. Nevertheless, there are additional requirements for the robustness of marine antifouling coatings, including the ability to withstand scratches and damage. Therefore, the demand for self-healing properties and robust mechanical strength is high, presenting significant challenges. Herein, inspired by the elastic surface and exceptional water absorption capabilities of dolphins, a reversible interlocking polymer network with multiple hydrogen bonds was successfully developed. This innovation harnesses the properties of poly(urethane-urea) and ureido pyrimidinone, thereby enhancing both mechanical properties and antifouling performance. Furthermore, the modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was incorporated into the system as a functional filler and to serve as crosslinking points, creating a multifunctional coating. Owing to the hierarchical hydrogen bonds (the hydrogen-bonded carbonyl groups in SPPU-01 reach as high as 56.80 %), SPPU-01 exhibits exceptional strength of 17.35 MPa (1132.17 %), remarkable toughness of 89.33 MJ/m 3 , and superior tear strength of 74.97 KN/m. Upon incorporating additional components, the composite crosslinking network enhances hydrophilicity (∼29.15°), thereby forming a hydration layer that effectively prevents fouling. The SPPU-02 reveals outstanding resistance to marine bacteria, effective anti-diatom adhesion, robust anti-mussel attachment, and strong anti-pseudo-barnacle properties, achieving 96.5 %, 94.5 %, 96.04 %, and 1.31 MPa, respectively. Furthermore, this strategy, which mimics dolphin functions, is well-suited for various marine materials with different requirements. It exhibits deicing (21.22 kPa), drag reduction, and high-temperature resistance properties (69.1 %), opening new avenues for the development of antifouling coatings with both strong and superior comprehensive performance.