Self-healing superhydrophobic anti-corrosion coating with dual photo-thermal and pH response for effective anti-icing and de-icing

In this study, a self-healing superhydrophobic bilayer coating with dual photothermal and pH response was developed by combining a smart self-healing bottom layer with a superhydrophobic top layer. The composite material (MZT) obtained by combining zeolitic imidazolate framework-8 (ZIF-8) loaded with corrosion inhibitor AMT (2-amino-5-mercapto-1,3,4-thiadiazole) and Ti 3 C 2 T X nanosheets (MXene) was embedded with a shape memory coating (SMP) as the bottom coating. The bottom coating is photo-thermal as well as pH dual-responsive, enabling smart self-healing. Under near-infrared (NIR) light irradiation, the MXene can effectively heal scratches in the coating by utilizing the photothermal effect. Even after the coating is subjected to severe corrosion, a change in pH will cause ZIF-8 to dissociate and release corrosion inhibitors to further protect the metal. In addition, the stearic acid-modified ZIF-8 combined with MXene to form a top layer coating (MZSA), and a superhydrophobic surface with a photothermal effect was prepared, with a contact angle of 159.3°. Under the irradiation of near-infrared light, it has good anti-icing/de-icing performance. The Electrochemical impedance spectroscopy (EIS) results showed that |Z| f=0.01 Hz of the composite coating was as high as 4.47 × 10 9 Ω⋅cm 2 after 40 days of immersion in 3.5 wt% NaCl solution, which was four orders of magnitude higher than that of the SMP coating.