Density functional theory based treatment of amino acids adsorption on single-walled carbon nanotubes

In this paper, the adsorption of a few amino acids on (10, 0) carbon nanotubes (CNTs) were investigated through calculations within density functional theory based methods. Results show that the zwitterionic-glycine adsorption is bound stronger to the nanotube surface in comparison to nonionic-glycine counterparts, as well as on phenylalanine, histidine and cysteine side chain groups. Our calculations indicate that, when zwitterionic-glycine was adsorbed on the CNTs wall the C–C bond of glycine was broken and a CO2 molecule was released. Furthermore, the mechanism of the C–C bond breaking is studied by density functional based tight binding molecular dynamics calculations which have been carried out at room temperature.