Amine-functionalization of carbon nanotubes assisted by electrochemical generation of chlorine

Electrochemical functionalization methods suffer from long processing time and lower efficiency. In this work, a simple single-step functionalization process with relatively higher efficiency and lower processing time is introduced. Different analyses were used to study it including Ultraviolet-visible absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy, energy dissipative spectroscopy (EDS) and transmission electron microscopy (TEM). The presence of chlorine produced by the electrochemical reactions on the surface of the CNTs was confirmed by EDS. In addition, UV-vis absorption of the chlorine decreases in the presence of CNTs probably because of chemisorption with CNTs, followed by the substitution of chlorine by ethylenediamine on the CNTs surface. Furthermore, the existence and amount of amine groups on the CNTs' surface were confirmed and measured by FTIR and TGA, respectively. UV-vis and TGA analysis of the prepared samples showed that the amination efficiency and the dispersibility of CNTs were higher in this method. Moreover, TEM images revealed higher surface roughness comparing with pristine CNT. Such higher roughness could imply the partial damage of graphite structure due to functionalization.