Structural Transformations of Carbon and Boron Nitride Nanoscrolls at High Impact Collisions

TL;DR

This study uses atomistic simulations to explore how carbon and boron nitride nanoscrolls behave under high-velocity impacts, revealing deformation, unscrolling, unzipping, and topology changes depending on impact conditions.

Contribution

It provides detailed atomistic insights into the collision-induced transformations of nanoscrolls, including deformation, unscrolling, and topology conversion, which were not fully understood before.

Findings

Large-scale deformations and fractures occur at specific velocities and orientations.

Unscrolling and unzipping into nanoribbons are observed during impacts.

Topology conversion from open to closed structures is possible due to fusion.

Abstract

The behavior of nanostructures under high strain-rate conditions has been object of theoretical and experimental investigations in recent years. For instance, it has been shown that carbon and boron nitride nanotubes can be unzipped into nanoribbons at high velocity impacts. However, the response of many nanostructures to high strain-rate conditions is still not completely understood. In this work we have investigated through fully atomistic reactive (ReaxFF) molecular dynamics (MD) simulations the mechanical behavior of carbon (CNS) and boron nitride nanoscrolls (BNS) colliding against solid targets at high velocities,. CNS (BNS) nanoscrolls are graphene (boron nitride) membranes rolled up into papyrus-like structures. Their open-ended topology leads to unique properties not found in close-ended analogues, such as nanotubes. Our results show that the collision products are mainly determined by impact velocities and by two impact angles, which define the position of the scroll (i) axis and (ii) open edge relative to the target. Our MD results showed that for appropriate velocities and orientations large-scale deformations and nanoscroll fracture can occur. We also observed unscrolling (scrolls going back to quasi-planar membranes), scroll unzipping into nanoribbons, and significant reconstruction due to breaking and/or formation of new chemical bonds. For particular edge orientations and velocities, conversion from open to close-ended topology is also possible, due to the fusion of nanoscroll walls.