Raman Studies of Carbon Nanotubes and Polymer Nanotube Composites

Abstract

In this paper, we present Raman studies of different carbon nanotubes systems like single-walled nanotubes(SWNTs), multi-walled nanotubes(MWNTs)or composites prepared with different conjugated or non-conjugated polymers. We have focused our studies on the interactions that can take place in these systems and in general modify the characteristics of individual tubes. By introducing Van der Waals interactions between tubes, we are able to interpret experimental Raman spectra. In the case of SWNTs, we have put in evidence the so-called“bundle”effect that consists of an upshift of the frequency of the RBM of 10 to 16 cm−1, depending on the size of the bundles. In MWNTs, one can calculate the low frequency Raman modes observed experimentally. We found that they originate from the radial breathing modes of isolated tubes with an upshift that depends on the number of shells constituting the tube and we were then able to calculate the intensity of such modes.Finally, in polymer/nanotubes composites, we demonstrate that interactions take place between the two constituents in two different cases: PPV/SWNTs and PANI/SWNTs. The role of the method of preparation of composites is particularly put in evidence.