Abstract: In this work, a versatile strategy of manipulating defective metal organic frameworks (MOFs) with the assistance of the steric hindrance effect was proposed and applied in coatings. The steric hindrance effect was utilized to construct the defective MOFs with phosphate, gluconate and phytate as examples. The defective MOFs were synthesized in an aqueous solution at room temperature, having a promising future for industrial application. Tailoring specific defects in MOFs can make molecular chains of polymer penetrate into the internal skeleton and form an interlocking structure. The interlocking effect can enhance the mechanical performance of the coating, and the corrosion inhibition performance of anions can synergistically improve the corrosion resistance of the coating. The waterborne acrylic resin (WAR) embedded with phytate-modified MOF has the highest tensile strength of 23.9 MPa, four times higher than pure WAR. Anti-corrosion test results indicated that the corrosion inhibition efficiencies of composite coatings maintained around 97 % after 2 months of immersion in seawater. The structure-property relations of defect-engineered MOFs and the anti-corrosion mechanisms were elaborated in detail by both experiments and molecular dynamics simulation. This strategy has excellent environmental friendliness, reduces the cost of MOF materials, and has broad application prospects.

Key words: Coating, Anti-corrosion, Defect-engineer, Metal organic framework