Comprehensive study of threonine adsorption on carbon nanotube: A dispersion complemented density functional theory-based treatment

Abstract

The interaction mechanism of threonine (Thr) on the sidewall of (8, 8) single-walled carbon nanotubes (CNTs) was investigated by density functional tight-binding method. All the functional groups of Thr were used to interact with the surface of CNT. The structural parameters were analyzed to identify the noncovalent interactions, and the binding energy and strain energy were used to indicate the binding properties. We found that the CH/π interactions play more important roles than NH/π and OH/π interactions in stabilizing the complex structures. Furtherly, the charge transfer properties, density of states (DOS) and partial density of states, and highest occupied molecular orbitals and lowest unoccupied molecular orbitals were also studied to illustrate the adsorbed interactions. The results show that the DOS structure of CNT could be modified by the adsorption of Thr, and, therefore, the conductivity of CNT will be improved by introducing proper amino acids. Our data should be helpful for the design of biocompatible molecules for CNT modification. © 2015 Wiley Periodicals, Inc.