Intrinsic electronic property and adsorption of organic molecules on specific iron surface: an ab initio DFT and DFTB study

An ab initio density functional theory (DFT) calculation revealed the electronic properties of azomethine functionalised epoxy, namely, 4-((oxiran-2-yl)methoxy)-N-(4-(4-(4-((oxiran-2-yl)methoxy)benzylideneamino)phenoxy)benzylidene)benzenamine (DSBE) and amine based curing agent namely diethylenetriamine (DETA), triethylenetetraamine (TETA) and para-phenylenediamine (PPD) responsible for its adsorption on the mild steel surface. The frontiers molecular orbitals (FMOs) and the corresponding energies as well as global softness values revealed the reactive nature of the studied organic molecules. The probable trends of the chemical properties of different amine cured epoxy have been predicted. The insights of the adsorption of these organic molecules have been visualized through density functional tight binding calculation. It revealed that these organic molecules are able to adsorb onto targeted metal surface viz. Fe(110), FeO(110) and Fe2O3(110) plane through charge density sharing occurring at the molecule-iron layer interface. Thus, a complete theoretical insight analysis and modelled simulated adsorption study provided a clear picture regarding the adsorptions of the organic molecules onto metallic surfaces.