In‐Situ Zinc‐Organic Coordination Domains Inside Polyurethane Coatings for Superior Corrosion Protection of Mild Steel

ABSTRACT Corrosion causes over US $2.5 trillion in annual economic losses, driving the need for protective polymer coatings that combine barrier effectiveness with active inhibition. Conventional ex‐situ mixing MOFs into polymer matrices often suffer from particle aggregation and poor interfacial adhesion, resulting in localized failure. To address this limitation, a one‐pot in‐situ route is reported, in which zinc‐carboxylate coordination domain derived from bi‐linker system (Zn‐BMOF) form inside a polyurethane matrix by separating the zinc source (isocyanate side) from the linkers (polyol side). FTIR, XRD, UV‐Vis, SEM‐EDX, TEM/SAED and AFM confirmed the formation in‐situ of well‐dispersed submicron Zn‐BMOF domains (0.5–0.9 µm) inside the PU matrix. The nanocomposite showed higher charge‐transfer resistance (5880 vs. 990 KΩ.cm 2 ), 13 times lower corrosion rate (0.0105 vs. 0.1362 mm.year −1 ), better thermal stability, adhesion, hardness and tensile strength and a reduction of 72% and 66% in oxygen permeability and moisture absorption, respectively. These developments highlight the potential of in‐situ MOF‐polymer integration a promising route toward durable anticorrosive coatings.