A multiscale computational study was conducted to investigate graphene-supported thin films composed of a
natural deep eutectic solvent (NADES) formed by menthol and decanoic acid (MENTH:DA), with a focus on
applications in sustainable CO₂ capture. Density functional theory (DFT) and molecular dynamics (MD) simulations were employed to elucidate interfacial structuring, molecular interactions, and gas adsorption behavior.
DFT results indicated a strong interaction between decanoic acid and the graphene surface (− 35.88 kJ/mol),
characterized by a parallel orientation that maximizes van der Waals interactions. In contrast, menthol displayed
weaker adsorption energies (− 5.15 kJ/mol) and a predominantly perpendicular orientation. MD simulations
revealed the formation of distinct adsorption layers, with decanoic acid enriched in the first layer and menthol in
the second, while the NADES hydrogen-bonding network remained largely intact. CO₂ exhibited preferential
adsorption over flue gas components (N₂, H₂O, O₂), with substantial accumulation in both the first and second
interfacial layers. Approximately 50% of the CO₂ content from flue gas mixtures was retained within the
structured region. Adsorption performance was found to be largely independent of temperature (303− 323K) and
NADES film thickness (20–50 Å). These results provide fundamental insight into NADES–graphene interactions
and highlight the potential of type V, naturally derived deep eutectic solvents as selective and environmentally
benign materials for CO₂ separation technologie
