Article: X-ray microdiffraction study of single-walled carbon nanotube alignment across a fiber, V. Pichot, M. Burghammer, S. Badaire, C. Zakri, C. Riekel, P. Poulin and P. Launois, EuroPhysics Lett. 79, 46002 (2007)
Carbon nanotubes, which are emblematic figures of nanosciences, are nano-components of macroscopic materials which could be used in the forthcoming years in miscellaneous areas such as: high mechanical performance materials, electro mechanical actuators, biological captors, chemical filters or flat screen devices. Because of the high ratio of the length over the diameter of the nanotubes (around 1000), it is of great importance to control their orientation inside the material.
X-Ray scattering allows quantitatively studying this orientation. It is usually performed with a beam which covers 1mm2 of the sample surface. However, we have shown that the use of synchrotron radiation could allow studying the nanotube alignment on a 1µm2 surface, which is one million times smaller. The experiment was performed at the ESRF in Grenoble on aligned single walled nanotube fibers synthesized at the CRPP in Pessac (France) (La Recherche Prize for CRPP and LPS teams). Such fibers are for instance very interesting because of their excellent capacity to absorb mechanical energy. We have shown that the alignment of the nanotubes is homogeneous from the core to the skin of the studied fiber, what is important to better understand its mechanical properties.
The possibility to analyse the structure and the texture of nanotube-based materials, from the millimetre to the micrometer, demonstrated on the single-walled nanotube fibers, opens the way for the study of the homogeneity of several other nanotube-based materials.
(a) Representation of a carbon nanotube
(b) Scheme of a nanotube fiber, green areas indicate the areas analyzed by microdiffraction from the core to the skin of the fiber.
(c) X-ray microdiffraction pattern in which the anisotropic angular signal (pointed with green arrows) allows one to measure the nanotube orientation.
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