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 CO(2) 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. (C) 2008 Elsevier B.V. All rights reserved.