# Diffusion behavior of water confined in deformed carbon nanotubes

## TL;DR

This study uses molecular dynamics simulations to explore how deformation of carbon nanotubes affects water diffusion, revealing structural transitions and mobility changes linked to nanotube shape alterations.

## Contribution

It demonstrates how nanotube deformation influences water's structural phase and diffusion behavior, highlighting the importance of shape in confined water dynamics.

## Key findings

- Water transitions from tubular-like to single-file structure with deformation.
- Deformation induces a shift from frozen to liquid water inside nanotubes.
- Diffusion enhancement or suppression correlates with hydrogen bond changes.

## Abstract

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7) nanotubes associated with a change from a high to low mobility regimes. The water which in the undeformed (9,9) nanotubes is frozen, becomes liquid for the distortion above a certain threshold. These water diffusion enhancement (suppresion) is related to a reduction (increase) in the number of hydrogen bonds. This suggests that the shape of the nanotube is a particularly important ingredient when considering the dynamical and structural properties of confined water.