In this work we report a theoretical study on the interaction of aniline with the side walls of end-capped(6,6) single wall carbon nanotube (SWCNT). To study this reaction, two-level ONIOM technique was employed where the higher level was treated with B3LYP/6-31G(d) DFT method and the lower level was described with UFF molecular mechanics. The results show thataniline prefers to be chemically adsorbed on the CNTssurface. Various thermodynamic parameters, including the Gibbs free energy (ΔGᵒ), enthalpy (ΔHᵒ),and entropy changes(ΔSᵒ) were calculated. The results indicated that the spontaneity of the adsorption, exothermic nature of the adsorption and the decrease in the randomness reported as ΔGᵒ , ΔHᵒ and ΔSᵒ,respectively, were all negative. It was found that the activation energy for adsorption of aniline is 39.66 kcal/mol. Furthermore, we find that when a aniline molecule was adsorbed on the carbon nanotubes, a [2+1] cycloadition chemical reaction take places. The study of the electronic structures and natural bond orbital analysis indicate that the aniline and CNT are interacting strongly, consistent with similar experimental observations [1]. All calculations were performed with the help of GAUSSIAN 09 [2] computational program.

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