Antisolvent precipitation of hydrophobic functionalized multiwall carbon nanotubes in an aqueous environment

Abstract

The possibility of antisolvent precipitation of hydrophobic, organic soluble functionalized carbon nanotubes (f-CNTs), where water acts as an antisolvent is presented. Octadecylamine functionalized multiwall carbon nanotubes (MWCNT-ODA) was used as the model compound and was found to form highly stable dispersions in different water/solvent systems, and the particle sizes ranged from 170 to 400. nm. Colloidal behavior was studied using dynamic light scattering and particle aggregation was found to increase with the addition of electrolytes, with tetrahydrofuran (THF) and ethanol showing the maximum effect. The aggregation behavior of the antisolvent precipitated system did not follow the conventional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which was different from what has been reported previously for hydrophilic, water soluble f-CNTs. Based on this study, it is evident that hydrophobic f-CNTs are potential water pollutants. © 2011 Elsevier Inc.