Wedge Radius Effects in Mechanical Exfoliation of HOPG: A Molecular Simulation Study

2014 ◽  
Author(s):  
B. Jayasena ◽  
S. Subbiah ◽  
C. D. Reddy
Keyword(s):  
Molecular Dynamics ◽  
Pyrolytic Graphite ◽  
Single Layer ◽  
Layered Material ◽  
Critical Depth ◽  
Graphene Layers ◽  
Highly Ordered Pyrolytic Graphite ◽  
Single Sheet ◽  
Dynamics Simulations ◽  
Atomically Flat

We study the effects of wedge bluntness in mechanically exfoliating graphene layers from highly ordered pyrolytic graphite (HOPG), a layered material. Molecular dynamics simulations show that the layer initiation modes strongly depend on the wedge radius. Force and specific energy signatures are also markedly affected by the radius. Cleaving with a larger wedge radius causes buckling ahead of the wedge; larger the radius more the buckling. A critical depth of insertion of 1.6 A° is seen necessary to cleave a single layer; this is also found to be independent of wedge radius. Hence, with accurate positioning on an atomically flat HOPG surface it is possible to mechanically cleave, using a wedge, a single sheet of graphene even with a blunt wedge.

A Molecular Dynamics Study of PDMS Stamp-Based Graphene Exfoliation

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Buddhika Jayasena ◽  
Shreyes N. Melkote
Keyword(s):  
Molecular Dynamics ◽  
Low Cost ◽  
Pyrolytic Graphite ◽  
Md Simulations ◽  
Process Conditions ◽  
Large Area ◽  
Pdms Stamp ◽  
Graphene Layers ◽  
Separation Force ◽  
Few Layer Graphene

Molecular dynamics (MD) simulations are used to gain insights into the process conditions that cause separation of graphene layers from a highly ordered pyrolytic graphite (HOPG) source in a polydimethylsiloxane (PDMS) stamp-assisted mechanical exfoliation process. Specifically, the effects of selected exfoliation process parameters and pre-existing defects, such as layer discontinuities in the graphite source, on the exfoliation process are investigated. The results show that exfoliation of individual and few layer graphene requires delicate control of the normal force applied to the HOPG by the PDMS stamp. The study also shows that defects (e.g., discontinuities) in the HOPG have a significant impact on the thickness of separated layers and the layer separation force. The insights derived from this study are expected to be very useful in the development of a low-cost, scalable, large area graphene production process.

Thermal conductivity of two-dimensional BC3: a comparative study with two-dimensional C3N

2019 ◽  
Vol 21 (24) ◽  
pp. 12977-12985 ◽  
Author(s):  
Jieren Song ◽  
Zhonghai Xu ◽  
Xiaodong He ◽  
Yujiao Bai ◽  
Linlin Miao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Comparative Study ◽  
Molecular Dynamics Simulations ◽  
Environmental Temperature ◽  
Single Layer ◽  
Two Dimensional ◽  
Vacancy Defects ◽  
Dynamics Simulations ◽  
External Strain

The thermal conductivities of single-layer BC3 (SLBC) sheets and their responses to environmental temperature, vacancy defects and external strain have been studied and compared with those of single-layer C3N (SLCN) sheets by molecular dynamics simulations.

scholarly journals A Molecular Dynamics Study on Wrinkles in Graphene with Simply Supported Boundary under In-Plane Shear

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jianzhang Huang ◽  
Qiang Han
Keyword(s):  
Molecular Dynamics ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Propagation Process ◽  
Plane Shear ◽  
Simply Supported ◽  
Layer Graphene ◽  
Out Of Plane ◽  
Formation And Evolution ◽  
Dynamics Simulations

The formation and evolution mechanisms of wrinkling in a rectangular single layer graphene sheet (SLGS) with simply supported boundary subjected to in-plane shear displacements are investigated using molecular dynamics simulations. Through investigating the out-of-plane displacements of the key point atom, we clarify the wrinkling growth and propagation process. Our results show that the boundary condition plays important roles in the wrinkling deformation. And the dependence of wrinkling parameters on the applied shear displacements is captured. Based on the elasticity theory, the formation mechanism of graphene wrinkling is revealed from the viewpoint of elastic energy. The effects of aspect ratio of graphene, temperature, and loading velocity on graphene wrinkling parameters and patterns are also investigated.

scholarly journals Amylin–Aβ oligomers at atomic resolution using molecular dynamics simulations: a link between Type 2 diabetes and Alzheimer's disease

2016 ◽  
Vol 18 (4) ◽  
pp. 2330-2338 ◽  
Author(s):  
Michal Baram ◽  
Yoav Atsmon-Raz ◽  
Buyong Ma ◽  
Ruth Nussinov ◽  
Yifat Miller
Keyword(s):  
Alzheimer’S Disease ◽  
Type 2 Diabetes ◽  
Alzheimer's Disease ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Single Layer ◽  
Atomic Resolution ◽  
Aβ Oligomers ◽  
Dynamics Simulations

Aβ1–42 oligomers prefer to interact with Amylin1–37 oligomers to form single layer conformations.

Molecular Dynamics Study of Cu Thin Film Deposition onβ-Ta

2002 ◽  
Vol 721 ◽  
Author(s):  
Peter Klaver ◽  
Barend J. Thijsse
Keyword(s):  
Molecular Dynamics ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Boundary Structure ◽  
Cu Films ◽  
Grain Boundary Structure ◽  
Cu Film ◽  
Cu Thin Film ◽  
Dynamics Simulations ◽  
Atomically Flat

AbstractMolecular Dynamics simulations were performed to study Cu film deposition on β-Ta. Three different β-Ta surfaces were used, two being atomically flat, and one resulting from Ta on Ta growth. We find that the Cu films develop a (111) texture with vertical grain boundaries between grains having different epitaxial relations with the β-Ta substrate. The epitaxial rotation angles were determined, as 5.2° and 10-13°, and the resulting strain reductions in the Cu films were identified. The effects of the substrate differences on the interfacial Ta/Cu intermixing and the epitaxy and grain boundary structure of the films are discussed.

Hydrogen Storage in Carbon Nanoscrolls: A Molecular Dynamics Study

2005 ◽  
Vol 885 ◽  
Author(s):  
Vitor Coluci ◽  
Scheila F. Braga ◽  
Ray H. Baughman ◽  
Douglas S. Galvão
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Internal Cavity ◽  
Multiwalled Carbon ◽  
Graphene Layers ◽  
Hydrogen Molecules ◽  
Carbon Nanoscrolls ◽  
Dynamics Simulations ◽  
Uptake Mechanisms

ABSTRACTWe carried out molecular dynamics simulations with Tersoff-Brenner potentials in order to investigate the hydrogen uptake mechanisms and storage capacity of carbon nanoscrolls (CNSs). CNSs are jelly roll-like structures formed by wrapping graphene layers. Interlayer adsorption is an option for this material, which does not exist for single and multiwalled carbon nanotubes. We analyzed the processes of hydrogen physisorption and uptake mechanisms. We observed incorporation of hydrogen molecules in both external and internal scroll surfaces. Insertion in the internal cavity and between the scroll layers is responsible for 40% of the total hydrogen adsorption at 77 K.

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