Spectroscopic Studies on Valine-Functionalized Single-Walled Carbon Nanotubes

The oxidized single-walled carbon nanotubes (SWCNTs) and valine-functionalized SWCNTs were prepared and characterized by using X-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), electron paramagnetic resonance (EPR), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) techniques. The XRD pattern of valine-functionalized SWCNTs was similar to the oxidized SWCNTs. UV-Vis study confirms that the formation of charge transfer complex, valine-functionalized SWCNTs. FT-IR study reveals that valine molecules have been bonded to SWCNTs. The line shape analysis shows that the EPR line shape is a Gaussian line shape. The EPR line width and g-factor values indicate the presence of impurities, defects or magnetic ion site in the samples. The surface morphology of the samples was observed by SEM images. EDX elemental micro analysis confirms that the nitrogen element exists in valine-functionalized SWCNTs.