Experimental and Simulation Investigation of Octadecyltriethoxysilane-Decorated Diatomaceous Earth Coatings with Enhanced Superhydrophobic and Self-Cleaning Properties

In this study, an effective diatomaceous earth (Dia)/octadecyltriethoxysilane (OTS)/epoxy resin (EP) with enhanced superhydrophobic and self-cleaning coating was prepared by spraying method, and the effect of OTS modification on the hydrophobicity of Dia materials was investigated through molecular dynamics computational simulation. The results showed that the number of hydrogen bonds and electrostatic interaction energy between diatomite and water molecules were significantly reduced after OTS modification, which significantly enhanced the hydrophobicity of diatomite. The coating exhibits excellent superhydrophobic properties, with a contact angle of up to 152.3°, and has a wide range of applicability, being able to uniformly cover a wide range of substrate surfaces such as glass, wood, and aluminium panels. In addition, it demonstrates excellent self-cleaning capabilities, effectively removing surface contaminants. The mechanical and chemical stability of the coating has also been thoroughly investigated, and it remains superhydrophobic even after abrasion tests and shows excellent stability in acidic or alkaline corrosive environments. Molecular dynamics calculations further elucidated the reason for the change in hydrophobicity of the coatings in acidic and alkaline environments, revealing that the diffusion of water molecules slows down in alkaline environments and solid–liquid interactions are enhanced, resulting in a slight decrease in hydrophobicity. The results of this study not only provide new ideas for the low-cost and environmentally friendly preparation of superhydrophobic materials but also provide a solid theoretical basis and practical guidance for further optimising the material properties.