Interfacial interaction of gas molecules and single-walled carbon nanotubes

The interfacial interaction between single-walled carbon nanotubes (SWNTs) and various gas molecules (H-2, He, and N-2) at different pressures has been probed by in situ x-ray absorption near-edge structure (XANES) spectroscopy. Experimental results reveal the different strength of interfacial interaction (involving external and internal collisions) between SWNTs and various gas molecules under different pressures. At gas pressures higher than 5 Torr, the unoccupied states of SWNTs show some features corresponding to the structure deformation with a reversible behavior when cycling under vacuum and gas conditions. The XANES study for different gases (H-2, He, and N-2) shows a strong dependence of gas molecular weight, which provides experimental evidence to the gas scattering mechanism. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4718421]