Edge Forces in Contacting Graphene Layers

2015 ◽  
Vol 82 (10) ◽  
Author(s):  
Jianxin Li ◽  
Hongwei Zhang ◽  
Zhengrong Guo ◽  
Tienchong Chang ◽  
Huajian Gao
Keyword(s):  
Molecular Dynamics ◽  
Plane Deformation ◽  
Md Simulations ◽  
Graphene Layers ◽  
Out Of Plane ◽  
Edge Force ◽  
Edge Damage

Temperature- and stiffness-dependent edge forces offer new mechanisms of designing nanodevices driven by temperature and stiffness gradients. Here, we investigate the edge forces in a graphene nanolayer on a spring supported graphene substrate based on molecular dynamics (MD) simulations. The dependences of the edge forces on the temperature and stiffness of the substrate are discussed in detail. Special attention is paid to the effect of the out-of-plane deformation of the substrate on the constituent edge forces and the resultant edge force. The results show that the deformation may lead to a significant redistribution of the constituent edge forces but does not change the resultant edge force, suggesting that particular caution should be exercised in designing nanodevices based on sliding graphene layers to avoid potential edge damage.

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.

Diffusion of Epoxy Molecules on the Chemically Modified Graphene: A Molecular Dynamics Simulation Study

2015 ◽  
Vol 817 ◽  
pp. 803-808 ◽  
Author(s):  
Jian Wei Zhang ◽  
Cai Jiang ◽  
Gang Shi ◽  
Da Zhi Jiang
Keyword(s):  
Molecular Dynamics ◽  
Polymer Composites ◽  
Functional Groups ◽  
Md Simulations ◽  
Molecular Structures ◽  
Dynamics Simulation ◽  
Graphene Layers ◽  
Wall Structures ◽  
Modified Graphene ◽  
Main Factor

Buckypaper based polymer composites provides a new technical approach toward realizing conductive/structural multifunctional composites. Resin infiltration in the buckypaper is critical for the fabrication of buckypaper/polymer composites. To investigate the micro-infusion process of the polymer inside the paper, molecular dynamics (MD) simulations are conducted to study the diffusion behavior of epoxy molecules on the modified graphene and between graphene layers. The graphene molecular structures are constructed to represent the wall structures of the carbon nanotubes. Diffusion coefficients of the epoxy molecules on the graphene modified with different functionalization densities and interlayer distances are calculated. The results indicate that the functional groups increase the interfacial interactions between the epoxy molecules and graphene, however, largely decrease the diffusion speeds of the epoxy molecule. The simulations on the graphene layer systems indicate that, the viscous resistance of the resin is the main factor for retarding the diffusion of the epoxy molecules for the unmodified graphene layers; while for the modified graphene layers, functional groups are the main factor for retarding the resin diffusion

Mechanics of a Graphene Flake Driven by the Stiffness Jump on a Graphene Substrate

2017 ◽  
Vol 84 (8) ◽  
Author(s):  
Hong Gao ◽  
Hongwei Zhang ◽  
Zhengrong Guo ◽  
Tienchong Chang ◽  
Li-Qun Chen
Keyword(s):  
Molecular Dynamics ◽  
Analytical Model ◽  
Driving Force ◽  
Md Simulations ◽  
Driving Mechanism ◽  
Graphene Flake ◽  
Working Temperature ◽  
Directional Motion ◽  
Edge Force ◽  
Motion Behavior

Intrinsic driving mechanism is of particular significance to nanoscale mass delivery and device design. Stiffness gradient-driven directional motion, i.e., nanodurotaxis, provides an intrinsic driving mechanism, but an in-depth understanding of the driving force is still required. Based on molecular dynamics (MD) simulations, here we investigate the motion behavior of a graphene flake on a graphene substrate with a stiffness jump. The effects of the temperature and the stiffness configuration on the driving force are discussed in detail. We show that the driving force is almost totally contributed by the unbalanced edge force and increases with the temperature and the stiffness difference but decreases with the stiffness level. We demonstrate in particular that the shuttle behavior of the flake between two stiffness jumps on the substrate can be controlled by the working temperature and stiffness configuration of the system, and the shuttle frequency can be well predicted by an analytical model. These findings may have general implications for the design of nanodevices driven by stiffness jumps.

Wrinkling in Graphene Subjected to Gradient Tension

NANO ◽  
2015 ◽  
Vol 10 (03) ◽  
pp. 1550037 ◽  
Author(s):  
Jianzhang Huang ◽  
Qiang Han
Keyword(s):  
Molecular Dynamics ◽  
Single Layer ◽  
Md Simulations ◽  
Area Ratio ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Out Of Plane ◽  
Displacement Direction ◽  
Effects Of Temperature ◽  
Plane Displacement

In the present study, the initiation and evolution mechanisms of wrinkles in a square single layer graphene sheet (SLGS) under gradient tensile displacements are investigated based on molecular dynamics (MD) simulations. The mechanism of wrinkling process is elucidated by studying the atomic out-of-plane displacements development of the key atoms in SLGS. It reveals that the loading and boundary conditions play dominant roles in the wrinkling deformation of graphene. The dependences of the wrinkling amplitude, wavelength, out-of-plane displacement, direction angle and wrinkling area ratio on the applied gradient tensile displacements are obtained. The effects of temperature, size of graphene and loading grads on graphene wrinkling are investigated.

scholarly journals Atomic Level Insight into Wetting and Structure of Ag Droplet on Graphene Coated Copper Substrate—Molecular Dynamics versus Experiment

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1465
Author(s):  
Aleksandra Drewienkiewicz ◽  
Arkadiusz Żydek ◽  
Marcela E. Trybula ◽  
Janusz Pstruś
Keyword(s):  
Molecular Dynamics ◽  
Copper Substrate ◽  
Md Simulations ◽  
Atomic Level ◽  
Wetting Behavior ◽  
Graphene Layers ◽  
Metal Interactions ◽  
Metal Metal ◽  
Perfect Graphene ◽  
Pure Cu

Understanding the atomic-level phenomena occurring upon the wetting of graphene-coated Cu with liquid Ag is pivotal for the description of the wetting phenomenon and the role of graphene as a diffusion barrier. We have performed molecular dynamics (MD) simulations and confronted with our present experimental results to characterize wetting behavior of graphene coated Cu surfaces. Perfect and defected graphene layers covering Cu surface were wetted with liquid Ag droplet at 1273 K. Structural and topological aspects are discussed to characterize structure of the liquid Ag droplet and a product of wetting reaction occurring on Cu/Gn and Cu/Gndef substrates, also including perfect graphene layer and a pure Cu surface. The obtained results reveal the importance of defects in graphene structure, which play a key role in wetting mechanism and the formation of AgCu alloy. As a consequence, we observe a change of the wetting behavior and topology of both bulk and adsorbed Ag atoms by using Voronoi analysis (VA). Despite the differences in time scale, atomistic simulations allowed us to catch the early stages of wetting, which are important for explaining the final stage of wetting delivered from experiment. Our findings reveal also graphene translucency to metal-metal interactions, observed in previous papers.

scholarly journals Study on Lightweight and Strengthening Effect of Carbon Nanotube in Highly Ordered Nanoporous Nickel: A Molecular Dynamics Study

2019 ◽  
Vol 9 (2) ◽  
pp. 352 ◽  
Author(s):  
Yu Zhou ◽  
Wu-Gui Jiang ◽  
Duo-Sheng Li ◽  
Qing-Hua Qin
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Tensile Modulus ◽  
Md Simulations ◽  
Absorption Capacity ◽  
Atomic Scale ◽  
Strengthening Effect ◽  
Pore Collapse ◽  
Out Of Plane

The mechanical behavior of nanocomposites consisting of highly ordered nanoporous nickel (HONN) and its carbon nanotube (CNT)-reinforced composites (CNHONNs) subjected to a high temperature of 900 K is investigated via molecular dynamics (MD) simulations. The study indicates that, out-of-plane mechanical properties of the HONNs are generally superior to its in-plane mechanical properties. Whereas the CNT shows a significant strengthening effect on the out-of-plane mechanical properties of the CNHONN composites. Compared to pure HONNs, through the addition of CNTs from 1.28 wt‰ to 5.22 wt‰, the weight of the composite can be reduced by 5.83‰ to 2.33% while the tensile modulus, tensile strength, compressive modulus and compressive strength can be increased by 2.2% to 8.8%, 1% to 5.1%, 3.6% to 10.2% and 4.9% to 10.7%, respectively. The energy absorption capacity can also be improved due to the existence of CNTs. Furthermore, the MD simulations provide further insights into the deformation mechanism at the atomic scale, including fracture in tension, pore collapse in compression and local changes in lattice structures due to stacking faults.

Layer-dependent Fracture Strength of Few-layer WS2 Induced by Interlayer Sliding: A Molecular Dynamics Study

2021 ◽  
Author(s):  
Hao Zhan ◽  
Xinfeng Tan ◽  
Xin Zhang ◽  
Guoxin Xie ◽  
Dan Guo
Keyword(s):  
Molecular Dynamics ◽  
Fracture Strength ◽  
Plane Deformation ◽  
Dynamics Simulation ◽  
Interlayer Interaction ◽  
Individual Layer ◽  
Out Of Plane ◽  
Relationship Of ◽  
Tip Radius

Abstract Understanding the relationship of interlayer interaction with mechanical properties and behaviors of two-dimensional layered materials (2DLMs) is critical in favoring the development of related nanodevices, nevertheless, still challenging due to the difficulties in experiments. In this work, nanoindentation simulations on few-layer WS2 were conducted by varying tip radius, suspended membrane radius and membrane size using molecular dynamics simulation. Consistent with our previous experimental results, few-layer WS2 exhibited layer-dependent reduction in fracture strength owing to the uneven stress distribution among individual layer induced by interlayer sliding under out-of-plane deformation. Besides, apparent curve hysteresis was observed due to interlayer sliding in the supported region when large tip radius and membrane radius were employed. However, instead of the supported part, the interlayer sliding within the suspended part resulted in the reduced fracture strength with the increase of layer number. These findings not only provide an in-depth comprehension on the influence of interlayer sliding on the fracture strength of few-layer WS2, but also suggest that the role of interlayer interaction should be seriously considered during nanodevice design.

Efficient Treatment of Fixed and Induced Dipolar Interactions

2000 ◽  
Vol 653 ◽  
Author(s):  
Celeste Sagui ◽  
Thoma Darden
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Lagrangian Formalism ◽  
Dipolar Interactions ◽  
Time Step ◽  
Efficient Treatment ◽  
Particle Mesh Ewald ◽  
Fixed Charges ◽  
Self Consistency ◽  
Induced Dipoles

AbstractFixed and induced point dipoles have been implemented in the Ewald and Particle-Mesh Ewald (PME) formalisms. During molecular dynamics (MD) the induced dipoles can be propagated along with the atomic positions either by interation to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lagrangian formalism. The use of PME for electrostatics of fixed charges and induced dipoles together with a CP treatment of dipole propagation in MD simulations leads to a cost overhead of only 33% above that of MD simulations using standard PME with fixed charges, allowing the study of polarizability in largemacromolecular systems.

Split the Charge Difference in Two! a Rule of Thumb for Adding Proper Amounts of Ions in MD Simulations

2020 ◽  
Author(s):  
Matías R. Machado ◽  
Sergio Pantano
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Simulations ◽  
Md Simulations ◽  
Good Practices ◽  
Rule Of Thumb ◽  
Ionic Concentrations

<p> Despite the relevance of properly setting ionic concentrations in Molecular Dynamics (MD) simulations, methods or practical rules to set ionic strength are scarce and rarely documented. Based on a recently proposed thermodynamics method we provide an accurate rule of thumb to define the electrolytic content in simulation boxes. Extending the use of good practices in setting up MD systems is promptly needed to ensure reproducibility and consistency in molecular simulations.</p>

Assessing the Antimalarial Potentials of Phytochemicals: Virtual Screening, Molecular Dynamics and In-Vitro Investigations

2019 ◽  
Vol 16 (3) ◽  
pp. 291-300
Author(s):  
Saumya K. Patel ◽  
Mohd Athar ◽  
Prakash C. Jha ◽  
Vijay M. Khedkar ◽  
Yogesh Jasrai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Integrity ◽  
Md Simulations ◽  
Tylophora Indica ◽  
Multidrug Resistance Protein 1 ◽  
Receptor Complexes ◽  
Resistance Protein ◽  
Dynamics Simulations ◽  
Stable Trajectory

Background: Combined in-silico and in-vitro approaches were adopted to investigate the antiplasmodial activity of Catharanthus roseus and Tylophora indica plant extracts as well as their isolated components (vinblastine, vincristine and tylophorine). </P><P> Methods: We employed molecular docking to prioritize phytochemicals from a library of 26 compounds against Plasmodium falciparum multidrug-resistance protein 1 (PfMDR1). Furthermore, Molecular Dynamics (MD) simulations were performed for a duration of 10 ns to estimate the dynamical structural integrity of ligand-receptor complexes. </P><P> Results: The retrieved bioactive compounds viz. tylophorine, vinblastin and vincristine were found to exhibit significant interacting behaviour; as validated by in-vitro studies on chloroquine sensitive (3D7) as well as chloroquine resistant (RKL9) strain. Moreover, they also displayed stable trajectory (RMSD, RMSF) and molecular properties with consistent interaction profile in molecular dynamics simulations. </P><P> Conclusion: We anticipate that the retrieved phytochemicals can serve as the potential hits and presented findings would be helpful for the designing of malarial therapeutics.

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