Universal anisotropic condensation transition of gases in nanotube bundles

TL;DR

This paper investigates the universal behavior of gas condensation transitions within nanotube bundles, highlighting how weak transverse interactions influence phase transition temperatures across different gases.

Contribution

It introduces a universal framework relating reduced critical temperature to transverse interactions in nanotube-confined gases, advancing understanding of phase transitions in quasi-one-dimensional systems.

Findings

Transition temperatures are lower due to weak transverse interactions.

Universal relation between reduced critical temperature and transverse interaction.

Condensation behavior can be expressed in a universal form.

Abstract

Gases adsorbed within bundles of carbon nanotubes (inside of the nanotubes or in the interstitial channels between the tubes) exhibit a variety of phase transitions with the help of interactions between molecules in neighboring channels or tubes. Because the channels/tubes are widely separated, these transverse interactions are weaker than the (longitudinal) interactions within the same channel. The transition temperatures that result are therefore lower than those of typical two- or three-dimensional transitions of the same species of molecules. We discuss here the condensation transition of such a gas to form a liquid, expressing the transition behavior in universal form, where the reduced critical temperature T_c* is a universal function of the reduced transverse interaction.