Tearing Graphene Sheets From Adhesive Substrates Produces Tapered Nanoribbons

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 6; no. 10; pp. 1108 - 1116
• Main Authors: Sen, Dipanjan, Novoselov, Kostya S., Reis, Pedro M., Buehler, Markus J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 21-05-2010; WILEY‐VCH Verlag
• Subjects: 2D materials; Crystals; Fracture mechanics; fractures; Graphene; Graphite - chemistry; mechanical properties; molecular dynamics; Molecular Dynamics Simulation; Nanocomposites; Nanomaterials; Nanostructure; Nanostructures - chemistry; Nanotechnology - methods; Surface Properties; Tearing; Two dimensional
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.201000097

Graphene is a truly two‐dimensional atomic crystal with exceptional electronic and mechanical properties. Whereas conventional bulk and thin‐film materials have been studied extensively, the key mechanical properties of graphene, such as tearing and cracking, remain unknown, partly due to its two‐dimensional nature and ultimate single‐atom‐layer thickness, which result in the breakdown of conventional material models. By combining first‐principles ReaxFF molecular dynamics and experimental studies, a bottom‐up investigation of the tearing of graphene sheets from adhesive substrates is reported, including the discovery of the formation of tapered graphene nanoribbons. Through a careful analysis of the underlying molecular rupture mechanisms, it is shown that the resulting nanoribbon geometry is controlled by both the graphene–substrate adhesion energy and by the number of torn graphene layers. By considering graphene as a model material for a broader class of two‐dimensional atomic crystals, these results provide fundamental insights into the tearing and cracking mechanisms of highly confined nanomaterials.
Tearing of graphene layers from adhesive substrates, such as SiO2 and poly(methyl methacrylate), leads to the formation of tapered ribbons, the angle of tapering increasing with adhesion strength. Being a truly two‐dimensional material, the tearing mechanics are governed by the in‐plane stretching energy of the graphene sheet, deviating from the behavior of macroscopic thin films.