Intertube interaction

It has been referred to that SWCNT forms a bundle or rope by aggregating several hundreds of SWCNTs in parallel [22]. Intertube interaction in such... 

M. Milnera, J. Kurd, M. Hulman, and H. Kuzmany, Periodic resonance excitation and intertube interaction from quasicontinuous distributed helicities in single-wall carbon nanotubes. Phys. Rev. Lett. 84, 1324-1327 (2000). 

There are two types of surface modifications for CNTs noncovalent interactions (Figure 6.54) and covalent sidewall (Figure 6.55) or defect-sitet (Figure 6.56) functionalization.Both methods, as well as physical techniques such as sonica-tion, are successful in separating individual SWNTs from bundles - a process known as exfoliation. In general, it is most desirable to incorporate isolated SWNTs in a composite rather than bundles, since the latter features poor intertube interactions resulting in a lower overall strength - especially at low CNT concentrations. 

In tins study, we report an evaluation of structural, mechanical, and vibrational prqierties of SWCNTs [C(n,n), and C(n,0), n=4,6,8,10], applying a FP-LCAO method (26,27), as it has previously been pointed out tiuit all-electron full-potential local density approximation (LDA)-based calculations are appropriate for treating van der Waals interactions in systems such as fiillerenes, gr hene and graphite (28,29). Although the full-potential all-electron scheme is conqiutationally intensive, our work contributes to the further validation of previous tiieoretical studies. Large-scale pseudopotential DFT calculations were also recently performed by Yoon et al. (30), in order to study the effects of intertube interactions on the transport properties of SWCNT junctions. 

We further investigated the effect of strain (e) on the tubes calculating Poisson s ratio (o), as listed in Table III. Intertube interactions appear to have overall a small effect on Poisson s ratio, although a higher response to an external force for small radii tubes was calculated. Our results were found to be lower than the tight-binding values (32,33). 

Since structural changes in carbon nanotubes can be in rtant for an accurate prediction of RBMs, it was interesting to note diat Henratd et al. (45) obtained a 10% increase in the RBM due to intertube interactions, which are higher than the observed experimental values, as reported by Kuzmany et al. 

Optical and Foss Spectra of Carbon Nanotubes Depolarization Effects and Intertube Interactions. 

It has been shown that at fixed laser energy, intertube interactions in bundles involve broadening and red-shifting of the interband transition [e.g., RBM bands]. The amplitude of this peak is strongly related to the inter-tube contact area, as well as to the orientation and compositional disorder in the sample. - - This is why Raman... 

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