Predicting paint resistance to pull-off by first principles calculations: The case of acrylic acid on (oxidised) metals

Paints are essential in everyday applications since they provide protective functions beyond aesthetics, such as corrosion resistance, UV shielding, and thermal performance enhancement. Adhesion is a critical factor governing the durability and performance of paints, yet the mechanisms controlling it at the atomic scale remain poorly understood. Here, we show that density functional theory (DFT) calculations can complement empirical adhesion tests and support the rational design of paint–substrate systems. We considered acrylic acid (a key component of acrylic paint) on pure and oxidised metallic substrates, including aluminium, iron, steel, alumina, hematite and goethite. The calculated adsorption energies and pull-off forces were compared with experimental paint breaking stress. The results show that acrylic acid binds more strongly to pristine metals than to oxides, and more in general the trends obtained across the considered substrates were in excellent agreement with the experiments, thereby establishing a quantitative correlation between molecular adsorption and macroscopic paint scratch. This approach offers a transferable route to design tailored coating–substrate systems, supporting applications in substrate protection and durability.