The low temperature thermal expansion of single-walled carbon nanotube bundles saturated with nitrogen

TL;DR

This study investigates how nitrogen impurities affect the low-temperature thermal expansion of single-walled carbon nanotube bundles, revealing significant increases and a peak around 28 K due to N2 saturation.

Contribution

It provides new insights into the impact of nitrogen saturation on the thermal expansion behavior of single-walled carbon nanotubes at cryogenic temperatures.

Findings

N2 saturation causes a sharp increase in thermal expansion coefficient.

A broad maximum in expansion occurs around 28 K.

Desorption of N2 occurs at low temperatures from the nanotube bundles.

Abstract

The effect of a N2 impurity on the radial thermal expansion coefficient (ar) of single-walled carbon nanotube bundles has been investigated in the temperature interval 2.2 - 43 K by the dilatometric method. Saturation of nanotube bundles with N2 caused a sharp increase in the positive magnitudes of ar in the whole range of temperatures used and a very high and wide maximum in the thermal expansion coefficient (ar)(T) at T about 28 K. The low temperature desorption of the impurity from the N2-saturated powder of bundles of single-walled carbon nanotubes with open and closed ends has been investigated.