Dispersion of denatured carbon nanotubes by using a dimethylformamide solution

Thi Thuy Nguyen, Sy Uan Nguyen, Dinh Tam Phuong, Duc Chien Nguyen and Anh Tuan Mai

Abstract

The dispersion of carbon nanotubes (CNTs) in liquid plays an important role in fundamental research and applied science. The most common technique applied to disperse CNTs is ultrasonication. The surfactants used for CNT dispersion are ethanol, sodium dodecyl benzenesulfonate (SDBS), dodecyltrimethylammonium bromide (DATB), sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS). This paper presents the dispersion of denatured CNTs by using a dimethylformamide (DMF) solution. The DMF is adsorbed on the surface of the nanotubes by a hydrophobic or π–π interaction. Ultrasonication helps DMF debundle the nanotubes by Coulombic or hydrophilic interaction, allowing the Van der Waals forces among the individual nanotubes to be overcome. UV–Vis spectra of dispersed CNTs in solution showed a maximum at 260 nm and decreased from UV to near IR. The vibration properties of the carbon samples were characterized with Raman spectroscopy, which illustrated the D and G bands of denatured CNTs at 1354 and 1581 cm⁻¹, respectively, different from the values of 1352 cm⁻¹ and 1580 cm⁻¹, respectively, for undenatured CNTs. Finally, the interaction between surfactants and nanotubes was studied by Fourier transform infrared spectroscopy (FTIR)