Structural support of the external tubes in double-wall carbon nanotubes

High-pressure Raman studies of double-wall carbon nanotubes (DWCNTs) and their parent single-wall carbon nanotubes provide experimental evidence of the structural support of carbon nanotubes due to the encapsulation of smaller diameter tubes in their interior. The structural support is manifested by the reduced slope of the radial breathing mode frequency of the external tubes in DWCNTs, which further decreases at higher pressures as the inner–outer tube (intratube) interaction increases.