Structural and electronic properties of folic acid adsorption on the carbon nanotubes: A Density Functional Theory study

Abstract

In this study, we studied the adsorption behavior of folic acid on the (5,0) zigzag and (5,5) armchair single-walled carbon nanotube (SWCNT) by Density Functional Theory (DFT). Geometry optimizations were carried out at the B3LYP/6-31G ∗ level of theory using the Gaussian 09 suite of programs. The adsorption energies, the quantum molecular descriptors analysis and the structural changes at the adsorption site are indicative of chemisorption (adsorption energy -31.673 kcal/mol) on the zigzag SWCNT surface, while the adsorption is physical (adsorption energy -9.70 kcal/mol) in nature on the armchair SWCNT surface. The density of the states (DOS) Plots, Natural bond orbital (NBO) analysis, and HOMO and LUMO are witness to the substantial changes in the electronic properties of the SWCNT systems after the attachment adsorbed species with the tube surface. These results are extremely relevant in order to diagnosis the potential applications of carbon nanotubes as drug delivery systems.