Experimental study and modeling of the wettability of fluorine graphene. Corrosion behavior of the fluorine graphene layer on a copper substrate

Fluorographene (FG) is a high-quality 2D insulator, which is effectively used as the atomically thin tunnel barrier. To date, the most common idea is that the complete fluorination of graphene (G) leads to an increase in hydrophobicity. We have shown that in reality fluorination leads to superhydrophilicity and to a significant increase in the defectiveness of the graphene layer. Without hydrocarbons, as well as due to the high defectiveness and superhydrophilicity, the corrosion current of FG is an order of magnitude higher than for pure copper and two orders of magnitude higher than for G synthesized on copper. The simulation results confirm experimental data on FG superhydrophilicity after prolonged fluorination. Thus, in order to achieve high hydrophilicity, it is not necessary to create hydroxyl groups on the surface of FG. A higher concentration of fluorine (the C/F composition ratio) is realized on a thicker copper plate with a graphene layer, compared to thin copper foil. Different fluorine concentrations are associated with different sizes of crystal grains, their orientation, as well as defectiveness and the number of graphene layers. The corrosive effect leads to a decrease in roughness and a multiple decrease in the amount of F on the FG.