The effect of sorbed hydrogen on low temperature radial thermal expansion of single walled carbon nanotube bundles

TL;DR

This study investigates how sorbed hydrogen affects the low-temperature radial thermal expansion of single-walled carbon nanotube bundles, revealing shifts in expansion behavior and increased magnitude due to hydrogen saturation.

Contribution

It provides new insights into the impact of hydrogen impurities on the thermal expansion properties of SWNT bundles at cryogenic temperatures.

Findings

Hydrogen saturation shifts negative thermal expansion to lower temperatures.

H2 saturation increases the magnitude of radial thermal expansion.

Desorption behavior of H2 from SWNT bundles was characterized.

Abstract

The effect of a normal H2 impurity upon the radial thermal expansion (Ar) of SWNT bundles has been investigated in the interval T = 2.2-27 K using the dilatometric method. It is found that H2 saturation of SWNT bundles causes a shift of the temperature interval of the negative thermal expansion towards lower (as compared to pure CNTs) temperatures and a sharp increase in the magnitude of (Ar) in the whole range of temperatures investigated. The low temperature desorption of H2 from a powder consisting of bundles of SWNTs, open and closed at the ends, has been investigated.