# QM/MM Dynamics Study of the Augmenting Effects of Reduced Graphene Oxide Towards the Butadiene Acrylonitrile Copolymer Matrix and Self-Repair of the Enhancer

## TL;DR

This paper uses advanced simulations to study how reduced graphene oxide strengthens a polymer material and enables self-repair at the atomic level.

## Contribution

The study reveals atomic-scale intermolecular interactions and self-repair mechanisms in rGO-enhanced polymer composites.

## Key findings

- 58 intermolecular interactions were identified, including hydrogen bonds and stacking types like π–π, σ–π, and σ–n.
- Five chemical processes within rGO were modeled, with two providing stabilization and others affecting the heteromaterial's constitution.
- A self-repair mechanism was observed in the rGO layer's carbon frame, specifically addressing vacancy defects.

## Abstract

This study utilizes QM/MM Born–Oppenheimer Molecular Dynamics in order to model the process of intermolecular binding between reduced graphene oxide (rGO) and butadiene–acrylonitrile copolymer (PBDAN) with a monomer ratio of 2:1. This research aims to elucidate the structural reasons behind the enhancing properties of the substrate, focusing on the polymer matrix. The behavior of each phase was examined and discussed. More importantly, the intermolecular interactions within the interphase zone of adsorption were investigated on an atomic scale. We found and characterized 58 such instances, grouped into hydrogen bonds and three types of stacking: π–π, σ–π, and σ–n. Each occurrence was analyzed through the use of radial distribution functions. Five spontaneous chemical processes within the rGO nanoparticle were modeled and characterized. Two of them were found to provide stabilization only within the substrate, while the rest are relevant for the overall constitution of the heteromaterial. Perhaps most intriguing is the process of self-repair as part of the vacancy defect. This occurs entirely within the carbon frame of the rGO layer. We believe our results to be of importance for a large set of ligand materials, mostly those which contain unsaturated bonds and electronegative atoms.