Impact of surfactant groups on the corrosion inhibition properties of superhydrophobic membranes on X80 steel

Fe2O3/Fe3O4 composite films were successfully prepared on the surface of X80 steel through hydrothermal synthesis and annealing treatments. Subsequently, the oxidised films were modified using surfactants such as decanoic acid (DA), decyl silane triol (DS) and perfluorodecyl silane triol (FDS), resulting in the creation of three distinct films exhibiting superhydrophobic properties. The effects of the hydrophilic and hydrophobic groups of surfactants on the superhydrophobic films of X80 steel were analysed using electrochemical methods, surface analysis techniques and theoretical calculations. The results showed that all three superhydrophobic films exhibited excellent corrosion resistance, with the order being DA > FDS > DS after 72 h of immersion in acidic conditions (pH = 6, 60 °C). Theoretical calculations showed that the adsorption performance of carboxyl groups was superior to that of silyl alcohol bonds, whereas fluorination of hydrophobic groups helped to enhance the adsorption capacity of hydrophilic groups. This not only reveals the key role of surfactants in the preparation of superhydrophobic membranes but also provides a theoretical basis for the preparation of superhydrophobic membranes on carbon steel surfaces.