Sustainable nanocomposite coatings for the protection of historic building surfaces: molecular simulation

The advancement of novel anti-corrosion coatings is essential for the preservation and maintenance of stone materials in heritage structures. This research investigates the synergistic effects of graphene and polytetrafluoroethylene (PTFE) in enhancing the corrosion resistance of epoxy coatings. Molecular dynamics simulations were utilized to construct models of pure epoxy resin (PR), graphene-reinforced epoxy resin (G/PR), and epoxy resin co-modified with graphene and PTFE (G/PTFE/PR), with the aim of assessing their corrosion resistance and mechanical performance. Findings indicate that the incorporation of graphene and PTFE markedly reduced the porosity within the epoxy resin matrix. Furthermore, the diffusion coefficients of water molecules and epoxy resin molecules in the G/PTFE/PR system decreased by 47% and 52%, respectively. The formation of hydrogen bonds between oxygen atoms in water molecules and hydrogen atoms in epoxy resin molecules was found to impede water molecule diffusion. Mechanical analysis via stress-strain curves revealed that the modified epoxy resin exhibited superior tensile strength. These results offer valuable insights for the development of advanced anti-corrosion coatings applicable to the conservation of historic buildings.

The molecular dynamics simulation software LAMMPS was employed to investigate the penetration process of a corrosive solution. To ensure the accuracy of the results, the appropriate empirical force field for polymers, known as PCFF, was utilized.