Effect of curvature on the mono-methylation of carbon belt surfaces using density functional theory

Abstract

The surface functionalization of single-walled carbon nanotubes (SWCNTs) by direct radical addition has received considerable attention. The introduction of substituents is useful for tuning the π-character, enhancing the substrate anchoring, and improving the solubility. In this study, we investigated the binding energies of mono-methylated carbon belts (short SWCNTs) using density functional theory to elucidate the effect of curvature. The binding energy decreased as the curvature κ decreased and was approximately 25 kcal mol−1 less for κ = 0.166 Å−1 than for κ = 0.364 Å−1. This is because a change in curvature significantly impacts the interaction energy between the CH3 moiety and the carbon belt portion but not the deformation energy of the system. These results suggest that curvature can control the grafting onto the SWCNT surface.