Preparation and characterization of aqueous dispersions based on single-walled carbon nanotubes functionalized with carboxyl anthracenes

In this work, we modified the surface of single-walled carbon nanotubes (SWCNTs) using anthracene derivatives with one or more hydrophilic carboxylic acid groups, including 1-anthracenecarboxylic acid, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, 9,10-anthracenedicarboxylic acid, 3-(anthracen-9-yl)propanoic acid and 9,10-anthrancenediyl-bis(methylene)dimalonic acid. We employed a simple method to mix SWCNTs with those anthracene derivatives by sonication in deionized water, after which the supernatant dispersions were collected after centrifugation. The experimental results showed that, with the facilitation of the carboxylic groups, the modified CNTs could be stably dispersed in deionized water (DI water). The stable CNTs-based aqueous dispersions could be used to fabricate conductive thin films by spray-coating. The obtained modified SWCNTs were also characterized by UV-Vis-NIR spectroscopy, fluorescence spectroscopy and Raman spectroscopy. The spectroscopic studies showed that only some slight changes were observed in the spectral profiles, indicating that no significant structural damages had occurred when the mild functionalization method was applied to CNTs.