Studying the Internal Structure of Carbon Nanotubes with SAXS
A polymer/multi-walled carbon nanotubes composite was measured with the SAXSpace system. The internal structure of the nanotubes was determined by calculating the electron density profile of the nanotube’s cross-section.
Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Composite materials containing CNTs exhibit interesting and novel properties which make them potentially useful in many fields, such as materials science, electronics, optics and others.
Small-angle X-ray scattering is sensitive to electron density variations in a material. Therefore, the internal structure of CNTs can be determined by calculating the electron-density profile of the cross-section.
Experimental and Results
A composite material consisting of multi-walled carbon nanotubes dispersed in a thermoplastic elastomer (urethane based) was measured with the SAXSpace system.
After subtracting the polymer scattering from the total signal, the scattering of the CNTs was obtained (Figure 1).
Fig. 1 Background-subtracted scattering curve
Their pair-distance distribution function (PDDF) was calculated by Indirect Fourier Transformation (IFT)1. This function was then converted ("deconvoluted")1 into the radial electron- density profile (Figure 2) using program DECON1.
Fig. 2 Radial electron density profile
The radial electron-density profile can be used to visualize the internal structure of the CNTs as shown in the scheme below:
1 O. Glatter, J. Phys.: Condens. Matter 18 (2006) 2403