Chirality manifestation in elastic coupling between the layers of double-walled carbon nanotubes
Résumé
A search for new relatively easy physicochemical methods for structural identification of carbon nanotubes represents a key challenge. Here, analyzing the experimental data on double-walled carbon nanotubes (DWCNTs) obtained by us and taken from literature, we have expressed the magnitude of elastic coupling between two tubular walls forming a DWCNT as a simple function dependent not only on DWCNT diameters but also on the difference between the chirality angles of the constituent nanotubes. To get this quite unexpected result, which allows us to relate more precisely the structural parameters of a DWCNT with frequencies of its radial breathing-like modes (RBLM), we have developed a new model for the RBLM dynamics that takes into account a possible deposition of water molecules from ambient air onto the DWCNT surface. The comparison between theoretical and experimental RBLM frequencies allows the evaluation of the handedness-dependent contribution in elastic coupling between the layers suggesting that, in the formation of DWCNTs, the layers with the same handedness are privilegeted. Application of the results for identification of DWCNTs is also considered.