Investigating the Multifunctional Coating Design for Metal Surfaces: Insights from Molecular Dynamics Simulations

This study employs molecular dynamics (MD) simulations to evaluate 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFTS) as a multifunctional SAM coating for aluminum surface and compares it with N-octyltriethoxysilane (OTES) (same headgroup, no perfluorinated tail) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFTCS) (similar tail, different headgroup). DFT calculations suggest that PFTS exhibits a high E _HOMO energy level, a small band gap, and very low chemical hardness, positioning it as the most effective inhibitor of corrosion and staining. Complementary MD simulations revealed that the PFTS-SAM has the highest binding energy (-124.68 kJ mol^-1 per molecule) compared with the OTES-SAM (-90.33 kJ mol^-1) and the PFTCS-SAM (-64.54 kJ mol^-1), indicating superior surface anchoring and stability. This is due to the synergistic effect of the trialkoxysilane headgroup, which promotes strong adhesion to the aluminum surface, and its robust perfluorinated tail, which enhances intermolecular interactions and contributes hydrophobicity. This dual functionality yields a stable SAM with exceptional anticorrosion and antistain properties. Contact angle analysis confirms the hydrophobic nature of the PFTS-SAM, while thermal stability analyses validate its resilience at elevated temperatures. Additionally, the stress-strain profile illustrates its robustness as a stable coating material. These results position PFTS as a high-performance single-component coating offering multifunctional protection and reduced maintenance, and demonstrate a transferable MD framework for evaluating advanced innovative coatings.