Scattering of Monatomic Gas Molecules on Vertically Aligned Single-Walled Carbon Nanotubes

Abstract

The scattering process of He molecules on vertically aligned single‐walled carbon nanotubes (VA‐SWNTs) was investigated using the molecular beam technique. The accommodation coefficients for VA‐SWNT films on quartz substrates at room temperature are remarkably high compared to those for bare surfaces, demonstrating the effectiveness of the surface modification technique with VA‐SWNT films for enhancing the energy transfer between gas molecules and surfaces. The enhanced energy transfer suggests that gas molecules can easily penetrate deep into the films because of their high porosity and suffer multiple collisions with bundles of SWNTs. The less effective energy accommodation at elevated temperatures, however, implies that the average number of collisions which gas molecules undergo before leaving the films is not large enough to maintain the perfect accommodation even at high temperature.