Dispersity and stability measurements of functionalized multiwalled carbon nanotubes in organic solvents

Multiwalled carbon nanotubes (MWCNTs) have attracted a great deal of attention due to their unique properties. However, due to interstrand van der Waals forces, their poor dispersity in aqueous or organic solvents has limited their practical applications. Chemical modification of their surfaces has been investigated in order to achieve good dispersity of MWCNTs in general and specifically regarding organic solvents. Because organic solvents are more suitable than water for processing various polymers, it is necessary for MWCNTs to be dispersed in organic solvents to allow the synthesis of polymer nanocomposites. To uniformly disperse MWCNTs in common organic solvents without the use of surfactants, acid treatment was carried out to introduce carboxyl groups, followed by alkylation with an alkyl halide to form alkylated MWCNTs. In this study, the effective dispersity of alkylated MWCNTs in acetone, toluene, and chloroform was observed by transmission electron microscopy. The dispersive stability of the MWCNTs over a period of 10 days was also investigated by using a Turbiscan optical analyzer. (C) 2009 Elsevier B. V. All rights reserved.