A Fully Atomistic Reactive Molecular Dynamics Study on the Formation of Graphane from Graphene Hydrogenated Membranes

2011 ◽  
Vol 1284 ◽  
Author(s):  
Pedro A. S. Autreto ◽  
Marcelo Z. Flores ◽  
Sergio B. Legoas ◽  
Ricardo P. B. Santos ◽  
Douglas S. Galvao
Keyword(s):  
Molecular Dynamics ◽  
Lattice Parameter ◽  
Plasma Exposure ◽  
Experimental Realization ◽  
Reactive Molecular Dynamics ◽  
Distribution Of Values ◽  
Carbon Carbon Bonds ◽  
Dynamics Simulations ◽  
Graphene Membranes

ABSTRACTRecently, Elias et al. (Science 323, 610 (2009).) reported the experimental realization of the formation of graphane from hydrogenation of graphene membranes under cold plasma exposure. In graphane, the carbon-carbon bonds are in sp3 configuration, as opposed to the sp2 hybridization of graphene, and the C–H bonds exhibit an alternating pattern (up and down with relation to the plane defined by the carbon atoms). In this work we have investigated, using reactive molecular dynamics simulations, the role of H frustration (breaking the H atoms up and down alternating pattern) in graphane-like structures. Our results show that a significant percentage of uncorrelated H frustrated domains are formed in the early stages of the hydrogenation process, leading to membrane shrinkage and extensive membrane corrugations. This might explain the significant broad distribution of values of lattice parameter experimentally observed. For comparison purposes we have also analyzed fluorinated graphane-like structures. Our results show that similarly to H, F atoms also create significant uncorrelated frustrated domains on graphene membranes.

The Dynamics of Formation of Graphane-like Fluorinated Graphene Membranes (Fluorographene): A Reactive Molecular Dynamics Study

2011 ◽  
Vol 1344 ◽  
Author(s):  
Ricardo P. B. Santos ◽  
Pedro A. S. Autreto ◽  
Sergio B. Legoas ◽  
Douglas S. Galvao
Keyword(s):  
Molecular Dynamics ◽  
Lattice Parameter ◽  
Hydrogen Atmosphere ◽  
Hydrogen Incorporation ◽  
Reactive Molecular Dynamics ◽  
Self Organized ◽  
Distribution Of Values ◽  
Carbon Losses ◽  
Good Agreement ◽  
Graphene Membranes

ABSTRACTUsing fully reactive molecular dynamics methodologies we investigated the structural and dynamical aspects of the fluorination mechanism leading to fluorographene formation from graphene membranes. Fluorination tends to produce significant defective areas on the membranes with variation on the typical carbon-carbon distances, sometimes with the presence of large holes due to carbon losses. The results obtained in our simulations are in good agreement with the broad distribution of values for the lattice parameter experimentally observed. We have also investigated mixed atmospheres composed by H and F atoms. When H is present in small quantities an expressive reduction on the rate of incorporation of fluorine was observed. On the other hand when fluorine atoms are present in small quantities in a hydrogen atmosphere, they induce an increasing on the hydrogen incorporation and the formation of locally self-organized structure of adsorbed H and F atoms.

scholarly journals Self-Driven Graphene Tearing and Peeling: A Fully Atomistic Molecular Dynamics Investigation

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 463-468 ◽  
Author(s):  
Alexandre F. Fonseca ◽  
Douglas S. Galvão
Keyword(s):  
Molecular Dynamics ◽  
Thermal Fluctuations ◽  
Atomic Scale ◽  
Nanometer Scale ◽  
Covalent Bonds ◽  
Reactive Molecular Dynamics ◽  
Carbon Carbon Bonds ◽  
Strain Release ◽  
Dynamics Simulations ◽  
External Forces

ABSTRACTIn spite of years of intense research, graphene continues to produce surprising results. Recently, it was experimentally observed that under certain conditions graphene can self-drive its tearing and peeling from substrates. This process can generate long, micrometer sized, folded nanoribbons without the action of any external forces. Also, during this cracking-like propagation process, the width of the graphene folded ribbon continuously decreases and the process only stops when the width reaches about few hundreds nanometers in size. It is believed that interplay between the strain energy of folded regions, breaking of carbon-carbon covalent bonds, and adhesion of graphene-graphene and graphene-substrate are the most fundamental features of this process, although the detailed mechanisms at atomic scale remain unclear. In order to gain further insights on these processes we carried out fully atomistic reactive molecular dynamics simulations using the AIREBO potential as available in the LAMMPS computational package. Although the reported tearing/peeling experimental observations were only to micrometer sized structures, our results showed that they could also occur at nanometer scale. Our preliminary results suggest that the graphene tearing/peeling process originates from thermal energy fluctuations that results in broken bonds, followed by strain release that creates a local elastic wave that can either reinforce the process, similar to a whip cracking propagation, or undermine it by producing carbon dangling bonds that evolve to the formation of bonds between the two layers of graphene. As the process continues in time and the folded graphene decreases in width, the carbon-carbon bonds at the ribbon edge and interlayer bonds get less stressed, thermal fluctuations become unable to break them and the process stops.

scholarly journals One Side-Graphene Hydrogenation (Graphone): Substrate Effects

MRS Advances ◽  
2016 ◽  
Vol 1 (20) ◽  
pp. 1429-1434 ◽  
Author(s):  
Cristiano Francisco Woellner ◽  
Pedro Alves da Silva Autreto ◽  
Douglas S. Galvao
Keyword(s):  
Molecular Dynamics ◽  
Pattern Formation ◽  
Electronic Transport ◽  
Cluster Formation ◽  
Substrate Type ◽  
Substrate Effects ◽  
Reactive Molecular Dynamics ◽  
Hydrogenated Graphene ◽  
Dynamics Simulations ◽  
Graphene Membranes

ABSTRACTRecent studies on graphene hydrogenation processes showed that hydrogenation occurs via island growing domains, however how the substrate can affect the hydrogenation dynamics and/or pattern formation has not been yet properly investigated. In this work we have addressed these issues through fully atomistic reactive molecular dynamics simulations. We investigated the structural and dynamical aspects of the hydrogenation of graphene membranes (one-side hydrogenation, the so called graphone structure) on different substrates (graphene, few-layers graphene, graphite and platinum). Our results also show that the observed hydrogenation rates are very sensitive to the substrate type. For all investigated cases, the largest fraction of hydrogenated carbon atoms was for platinum substrates. Our results also show that a significant number of randomly distributed H clusters are formed during the early stages of the hydrogenation process, regardless of the type of substrate. These results suggest that, similarly to graphane formation, large perfect graphone-like domains are unlikely to be formed. These findings are especially important since experiments have showed that cluster formation influences the electronic transport properties in hydrogenated graphene.

scholarly journals Reactive molecular dynamics simulation of the high-temperature pyrolysis of 2,2′,2′′,4,4′,4′′,6,6′,6′′-nonanitro-1,1′:3′,1′′-terphenyl (NONA)

RSC Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 5507-5515
Author(s):  
Liang Song ◽  
Feng-Qi Zhao ◽  
Si-Yu Xu ◽  
Xue-Hai Ju
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulation ◽  
Reactive Molecular Dynamics ◽  
Ring Compounds ◽  
Fused Ring ◽  
Dynamics Simulations

The bimolecular and fused ring compounds are found in the high-temperature pyrolysis of NONA using ReaxFF molecular dynamics simulations.

Exploring secondary interactions and the role of temperature in moisture-contaminated polymer networks through molecular simulations

Soft Matter ◽  
2021 ◽  
Vol 17 (10) ◽  
pp. 2942-2956
Author(s):  
Rishabh D. Guha ◽  
Ogheneovo Idolor ◽  
Katherine Berkowitz ◽  
Melissa Pasquinelli ◽  
Landon R. Grace
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Temperature Variation ◽  
Polymer Networks ◽  
Molecular Simulations ◽  
Effect Of Temperature ◽  
Secondary Interactions ◽  
Dynamics Simulations ◽  
Secondary Bonding

We investigated the effect of temperature variation on the secondary bonding interactions between absorbed moisture and epoxies with different morphologies using molecular dynamics simulations.

scholarly journals Towards designing globular antimicrobial peptide mimics: role of polar functional groups in biomimetic ternary antimicrobial polymers

Soft Matter ◽  
2021 ◽  
Author(s):  
Garima Rani ◽  
Kenichi Kuroda ◽  
Satyavani Vemparala
Keyword(s):  
Molecular Dynamics ◽  
Antimicrobial Peptide ◽  
Bacterial Membrane ◽  
Simulation Data ◽  
Antimicrobial Polymers ◽  
Polar Groups ◽  
Methacrylate Polymers ◽  
Dynamics Simulations ◽  
Polar Functional Groups

Using atomistic molecular dynamics simulations, we study the interaction of ternary methacrylate polymers, composed of charged cationic, hydrophobic and neutral polar groups, with model bacterial membrane. Our simulation data shows...

scholarly journals Molecular insights on poly(N-isopropylacrylamide) coil-to-globule transition induced by pressure

2021 ◽  
Vol 23 (10) ◽  
pp. 5984-5991
Author(s):  
Letizia Tavagnacco ◽  
Ester Chiessi ◽  
Emanuela Zaccarelli
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Polymer Chain ◽  
Linear Polymer ◽  
Dynamics Simulations ◽  
Linear Polymer Chain

By using extensive all-atom molecular dynamics simulations of an atactic linear polymer chain, we unveil the role of pressure in the coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM).

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