Surface functionalisation of multi-walled carbon nanotubes with tris(2-aminoethyl)amine and their characterisation

Abstract

Carbon nanotubes are widely employed in various applications because of its excellent properties. However, they generally suffer from the low dispersion into aqueous solutions. Many applications of carbon nanotubes require previous surface functionalisation. In present study, we report the surface functionalisation of multi-walled carbon nanotubes (MWCNTs) by grafting a tris(2-aminoethyl)amine (TAA) via a facile method. The pristine MWCNTs and TAA-functionalised MWCNTs (MWCNTs-TAA) are characterised by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Raman spectroscopy, thermal gravimetric analysis (TGA). The TEM image of MWCNTs-TAA exhibits significantly improved dispersion of the MWCNTs. The high-resolution FE-SEM images clearly show the opening ends of nanotubes after TAA functionalisation. The increase in nanotube diameters of MWCNTs-TAA is observed compared to the pristine MWCNTs. The strong absorption peak at 1530 cm−1 from FTIR spectra for MWCNTs-TAA indicates that the amine groups are successfully grafted onto the surface of MWCNTs. The TGA curves of MWCNTs-TAA reveal a weight loss in the temperature range of 200 to 450 °C attributed to the decomposition of the amine groups, and the highest weight loss is obtained to be 22.14 wt% after 12 h reaction time. This work demonstrates the facile and efficient method to functionalise MWCNTs with TAA.