Wrinkles in graphene suspended on flat substrates: structure and collapse under hydrostatic pressure

TL;DR

This study uses molecular dynamics simulations to explore how graphene sheets form, evolve, and collapse under various compression and hydrostatic pressure conditions, revealing stable wrinkle states and collapse mechanisms.

Contribution

It introduces a detailed simulation analysis of wrinkle formation, stability, and collapse in graphene under different compression modes and hydrostatic pressure.

Findings

Graphene forms stable linear wrinkles under uniaxial compression.

Multiple wrinkle states exist with varying energies and configurations.

A critical hydrostatic pressure causes wrinkles to flatten or collapse into folds.

Abstract

The method of molecular dynamics and molecular mechanics has been used to numerically simulate the formation of wrinkle systems during compression of a graphene sheet lying on a flat solid substrate. It is shown that under uniaxial compression the nanosheet can transition into several stable wrinkled states: the most energetically favorable one is a linear wrinkle of infinite length. Higher energy states include wrinkles of finite length aligned along the same line where their ends partially overlap. Under biaxial compression, the graphene nanosheet can contain one linear wrinkle or two linear non-intersecting or intersecting wrinkles corresponding to weak, medium and strong compression, respectively. There are several nanosheet states with intersecting wrinkles that differ in structure of intersection area. The effect of external hydrostatic pressure on the shape of wrinkles has been studied. It is shown that there is a critical pressure value at which the wrinkle either completely flattens (disappears) or collapses into a vertical two-layer fold (the first scenario is possible only with weak compression of the sheet).