Bio-inspired self-healing and anti-corrosion waterborne polyurethane coatings based on highly oriented graphene oxide

In the face of ubiquitous corrosion threats, the development of high-performance elastomer protective materials with active self-healing functions is extremely challenging and significant. We propose an approach by combining WPU elastomer with GO to create the multifunctional pearl layer structured polymers with interface hydrogen bonds. By crosslinking the polycaprolactone diol (PCL) chain with a hydrogen bond array, the elastomer with high mechanical strength, extensibility, elasticity, excellent damage resistance, and healing properties was successfully synthesized. The elastomer exhibits remarkable mechanical properties, including a tensile strength of 39.89 MPa, toughness value of 300.3 MJ m3, and fracture energy of 146.57 kJ m2. The enhanced damage resistance of the elastomer can be attributed to the decomposable hydrogen bond array as well as the strain-induced crystallization of PCL fragments, which effectively dissipate energy. Importantly, due to the reversibility of the hydrogen bonding array, the fractured WPU can easily heal and restore its original mechanical properties when subjected to heating at 50 °C. Moreover, the photothermal properties of GO enable the biomimetic polymer coating to achieve damage recovery after being irradiated with NIR for 30 s. The obtained biomimetic coating exhibits a highly oriented lamellar structure, thereby greatly enhancing physical barrier performance and anti-corrosion performance. Electrochemical impedance spectroscopy (EIS) shows that the impedance modulus is one order of magnitude higher than that of the blank coating. Additionally, scanning vibrating electrode (SVET) confirmed that the self-healing performance and protection effect of the biomimetic coating in 3.5 wt% NaCl solution were also reliable. This highly reliable biomimetic coating presents a revolutionary solution for creating multi-functional, high-performance smart material in harsh environments.