# Revealing the Innate Subnanometer Porous Structure of Carbon Nanomembranes with Molecular Dynamics Simulations and Highly-Charged Ion Spectroscopy

## TL;DR

This paper uses simulations and a new ion spectroscopy method to reveal the tiny porous structure of carbon nanomembranes.

## Contribution

The study introduces a novel method combining molecular dynamics and highly-charged ion spectroscopy to characterize CNM structure.

## Key findings

- CNMs likely contain under-coordinated carbon with subnanometer pores.
- The porous structure is reactive in air but stabilized by hydrogen and oxygen groups.
- Simulated ion charge exchange data matches experimental results.

## Abstract

Carbon nanomembranes (CNMs) are nanometer-thin disordered
carbon
materials that are suitable for a range of applications, from energy
generation and storage through to water filtration. The structure–property
relationships of these nanomembranes are challenging to study using
traditional experimental characterization techniques, primarily due
to the radiation sensitivity of the free-standing membrane. Highly
charged ion spectroscopy is a novel characterization method that is
able to infer structural details of the carbon nanomembrane without
concern about induced damage affecting the measurements. Here we employ
molecular dynamics simulations to produce candidate structural models
of terphenylthiol-based CNMs with varying degrees of nanoscale porosity
and compare predicted ion charge exchange data and tensile moduli
to experiment. The results suggest that the in-vacuum CNM composition
likely comprises a significant fraction of under-coordinated carbon,
with an open subnanometer porous structure. Such a carbon network
would be reactive in the atmosphere and would be presumably stabilized
by hydrogen and oxygen groups under atmospheric conditions.