Solubility of functionalized single-wall carbon nanotubes in water: a theoretical study

In this work, we perform an in silico functionalization of single-wall carbon nanotubes to model the apparent solubility, binding energies and to understand the dependence of such properties on the functionalization and the electronic properties. The present study is performed using two finite models of single-wall carbon nanotubes (SWCNTs), the first one is a SWCNT with metallic character and the second one is a SWCNT with semiconductor character. In addition, we use several functionalizing molecules reported in the literature: formic acid, triethylene glycol diamine, glucosamine, polyaminobenzene sulfonic acid, and polystyrene. We found that the molecule that confers a better apparent solubility to both models of SWCNTs, metallic and semiconductor, is glucosamine, due to the several hydroxyl groups in its structure, promoting a higher polarization of the system. At the same time, we found that metallic molecules promote higher polarization compared with the nonmetallic as it is observed in the electrostatic potential surfaces. Therefore, a single-wall carbon nanotube functionalized with glucosamine is suitable to show good solubility properties that can be related to a decrease in the toxicity and an increment in the biocompatibility properties. © 2017, Springer-Verlag GmbH Germany.

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