http://scholar.google.com/citations?hl=en&user=95SvbM8AAAAJ
1.
Jaques, Ygor M.; Galvao, Douglas S.
Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted) Journal Article
Em: Journal of Molecular Liquids, 2019.
@article{Jaques2019b,
title = {Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted)},
author = {Ygor M. Jaques and Douglas S. Galvao},
year = {2019},
date = {2019-02-05},
journal = {Journal of Molecular Liquids},
abstract = {The determination of the wettability of 2D materials is an area of intensive research, as it is decisive on the applications of these systems in nanofluidics. One important part of the wetting characterization is how the spreading of droplets impacting on the surfaces occurs. However, few works address this problem for layered materials. Here, we report a fully atomistic molecular dynamics study on the dynamics of impact of water nanodroplets (100 ̊A of diameter) at high velocities (from 1 up to 15 ̊A/ps) against graphene targets. Our results show that tuning graphene wettability (through parameter changes) significantly affects the structural and dynamical aspects of the nanodroplets. We identified three ranges of velocities with distinct characteristics, from simple deposition of the droplet to spreading with rebound, and finally droplet frag- mentation. We also identify that in an intermediary velocity of 7 ̊A/ps, the pattern of spreading critically changes, due to formation of voids on droplet structure. These voids affect in a detrimental way the droplet spreading on the less hydrophilic surface, as it takes more time to the droplet recover from the spreading and to return to a semi-spherical configuration. When the velocity is increased to values larger than 11 ̊A/ps, the droplet fragments, which reveals the maximum possible spreading.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The determination of the wettability of 2D materials is an area of intensive research, as it is decisive on the applications of these systems in nanofluidics. One important part of the wetting characterization is how the spreading of droplets impacting on the surfaces occurs. However, few works address this problem for layered materials. Here, we report a fully atomistic molecular dynamics study on the dynamics of impact of water nanodroplets (100 ̊A of diameter) at high velocities (from 1 up to 15 ̊A/ps) against graphene targets. Our results show that tuning graphene wettability (through parameter changes) significantly affects the structural and dynamical aspects of the nanodroplets. We identified three ranges of velocities with distinct characteristics, from simple deposition of the droplet to spreading with rebound, and finally droplet frag- mentation. We also identify that in an intermediary velocity of 7 ̊A/ps, the pattern of spreading critically changes, due to formation of voids on droplet structure. These voids affect in a detrimental way the droplet spreading on the less hydrophilic surface, as it takes more time to the droplet recover from the spreading and to return to a semi-spherical configuration. When the velocity is increased to values larger than 11 ̊A/ps, the droplet fragments, which reveals the maximum possible spreading.
2.
Ygor M.; Galvao Jaques, Douglas S.
Structural Properties of Nanodroplets Impacting Graphene at High Velocities Online
2018, (Preprint ArXiv:1804.07784).
@online{Jaques2018d,
title = {Structural Properties of Nanodroplets Impacting Graphene at High Velocities},
author = {Jaques, Ygor M.; Galvao, Douglas S.},
url = {https://arxiv.org/abs/1804.07784},
year = {2018},
date = {2018-04-24},
abstract = {We report here a fully atomistic molecular dynamics study on the dynamics of impact of water
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion. },
note = {Preprint ArXiv:1804.07784},
keywords = {},
pubstate = {published},
tppubtype = {online}
}
We report here a fully atomistic molecular dynamics study on the dynamics of impact of water
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion.
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion.
3.
Leonardo Dantas Machado José Moreira de Sousa, Cristiano Francisco Woellner; Galvao, Douglas S.
Carbon Nanoscrolls at High Impacts: A Molecular Dynamics Investigation Journal Article
Em: MRS Advances, vol. 2016, 2016.
@article{deSousa2016b,
title = {Carbon Nanoscrolls at High Impacts: A Molecular Dynamics Investigation},
author = {José Moreira de Sousa, Leonardo Dantas Machado, Cristiano Francisco Woellner, Pedro Alves da Silva Autreto and Douglas S. Galvao},
url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10242265&fulltextType=RA&fileId=S2059852116002000},
doi = {10.1557/adv.2016.200},
year = {2016},
date = {2016-03-01},
journal = {MRS Advances},
volume = {2016},
abstract = {The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.
4.
Ygor M. Jaques, Gustavo Brunetto; Galvão, Douglas S.
Nanodroplets Impacting on Graphene Journal Article
Em: MRS Advances, vol. 2016, 2016.
@article{Jaques2016b,
title = {Nanodroplets Impacting on Graphene},
author = {Ygor M. Jaques, Gustavo Brunetto and Douglas S. Galvão},
url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10253580&fulltextType=RA&fileId=S2059852116002218},
doi = {DOI: 10.1557/adv.2016.221},
year = {2016},
date = {2016-03-01},
journal = {MRS Advances},
volume = {2016},
abstract = {The unique and remarkable properties of graphene can be exploited as the basis to a wide
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The unique and remarkable properties of graphene can be exploited as the basis to a wide
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.
2019
4.
Jaques, Ygor M.; Galvao, Douglas S.
Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted) Journal Article
Em: Journal of Molecular Liquids, 2019.
Resumo | BibTeX | Tags: droplets, Graphene, Impact Molecular Dynamics, water
@article{Jaques2019b,
title = {Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted)},
author = {Ygor M. Jaques and Douglas S. Galvao},
year = {2019},
date = {2019-02-05},
journal = {Journal of Molecular Liquids},
abstract = {The determination of the wettability of 2D materials is an area of intensive research, as it is decisive on the applications of these systems in nanofluidics. One important part of the wetting characterization is how the spreading of droplets impacting on the surfaces occurs. However, few works address this problem for layered materials. Here, we report a fully atomistic molecular dynamics study on the dynamics of impact of water nanodroplets (100 ̊A of diameter) at high velocities (from 1 up to 15 ̊A/ps) against graphene targets. Our results show that tuning graphene wettability (through parameter changes) significantly affects the structural and dynamical aspects of the nanodroplets. We identified three ranges of velocities with distinct characteristics, from simple deposition of the droplet to spreading with rebound, and finally droplet frag- mentation. We also identify that in an intermediary velocity of 7 ̊A/ps, the pattern of spreading critically changes, due to formation of voids on droplet structure. These voids affect in a detrimental way the droplet spreading on the less hydrophilic surface, as it takes more time to the droplet recover from the spreading and to return to a semi-spherical configuration. When the velocity is increased to values larger than 11 ̊A/ps, the droplet fragments, which reveals the maximum possible spreading.},
keywords = {droplets, Graphene, Impact Molecular Dynamics, water},
pubstate = {published},
tppubtype = {article}
}
The determination of the wettability of 2D materials is an area of intensive research, as it is decisive on the applications of these systems in nanofluidics. One important part of the wetting characterization is how the spreading of droplets impacting on the surfaces occurs. However, few works address this problem for layered materials. Here, we report a fully atomistic molecular dynamics study on the dynamics of impact of water nanodroplets (100 ̊A of diameter) at high velocities (from 1 up to 15 ̊A/ps) against graphene targets. Our results show that tuning graphene wettability (through parameter changes) significantly affects the structural and dynamical aspects of the nanodroplets. We identified three ranges of velocities with distinct characteristics, from simple deposition of the droplet to spreading with rebound, and finally droplet frag- mentation. We also identify that in an intermediary velocity of 7 ̊A/ps, the pattern of spreading critically changes, due to formation of voids on droplet structure. These voids affect in a detrimental way the droplet spreading on the less hydrophilic surface, as it takes more time to the droplet recover from the spreading and to return to a semi-spherical configuration. When the velocity is increased to values larger than 11 ̊A/ps, the droplet fragments, which reveals the maximum possible spreading.
2018
3.
Ygor M.; Galvao Jaques, Douglas S.
Structural Properties of Nanodroplets Impacting Graphene at High Velocities Online
2018, (Preprint ArXiv:1804.07784).
Resumo | Links | BibTeX | Tags: droplets, Graphene, Impact Molecular Dynamics, water
@online{Jaques2018d,
title = {Structural Properties of Nanodroplets Impacting Graphene at High Velocities},
author = {Jaques, Ygor M.; Galvao, Douglas S.},
url = {https://arxiv.org/abs/1804.07784},
year = {2018},
date = {2018-04-24},
abstract = {We report here a fully atomistic molecular dynamics study on the dynamics of impact of water
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion. },
note = {Preprint ArXiv:1804.07784},
keywords = {droplets, Graphene, Impact Molecular Dynamics, water},
pubstate = {published},
tppubtype = {online}
}
We report here a fully atomistic molecular dynamics study on the dynamics of impact of water
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion.
nanodroplets (50, 100 and 120 Å of diameter) at high velocity (from 100 up to 1000 m/s) against
graphene targets. Our results show that tuning graphene wettability (through parameter changes)
significantly affects the structural and dynamical aspects of the nanodroplets. We identified three
ranges of velocities with distinct characteristics, from simple deposition of the droplet to
spreading with rebound and finally fragmentation. At Weber numbers lower than 10, the droplets
maintain a steady spreading factor independent of size. After this threshold value, the spread
rapidly grows with increasing Weber numbers. A more hydrophilic graphene surface increases
the spreading values, due to stronger solid-liquid interactions. Nevertheless, droplet size also
influences the fragmentation threshold, as an increased number of molecules make it easier for
the whole droplet overcomes the surface repulsion.
2016
2.
Leonardo Dantas Machado José Moreira de Sousa, Cristiano Francisco Woellner; Galvao, Douglas S.
Carbon Nanoscrolls at High Impacts: A Molecular Dynamics Investigation Journal Article
Em: MRS Advances, vol. 2016, 2016.
Resumo | Links | BibTeX | Tags: Impact Molecular Dynamics, nanoscrolls
@article{deSousa2016b,
title = {Carbon Nanoscrolls at High Impacts: A Molecular Dynamics Investigation},
author = {José Moreira de Sousa, Leonardo Dantas Machado, Cristiano Francisco Woellner, Pedro Alves da Silva Autreto and Douglas S. Galvao},
url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10242265&fulltextType=RA&fileId=S2059852116002000},
doi = {10.1557/adv.2016.200},
year = {2016},
date = {2016-03-01},
journal = {MRS Advances},
volume = {2016},
abstract = {The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.},
keywords = {Impact Molecular Dynamics, nanoscrolls},
pubstate = {published},
tppubtype = {article}
}
The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.
1.
Ygor M. Jaques, Gustavo Brunetto; Galvão, Douglas S.
Nanodroplets Impacting on Graphene Journal Article
Em: MRS Advances, vol. 2016, 2016.
Resumo | Links | BibTeX | Tags: Graphene, Impact Molecular Dynamics, nanodroplet
@article{Jaques2016b,
title = {Nanodroplets Impacting on Graphene},
author = {Ygor M. Jaques, Gustavo Brunetto and Douglas S. Galvão},
url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10253580&fulltextType=RA&fileId=S2059852116002218},
doi = {DOI: 10.1557/adv.2016.221},
year = {2016},
date = {2016-03-01},
journal = {MRS Advances},
volume = {2016},
abstract = {The unique and remarkable properties of graphene can be exploited as the basis to a wide
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.},
keywords = {Graphene, Impact Molecular Dynamics, nanodroplet},
pubstate = {published},
tppubtype = {article}
}
The unique and remarkable properties of graphene can be exploited as the basis to a wide
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.
range of applications. However, in spite of years of investigations there are some important
graphene properties that are not still fully understood, as for example, its wettability. There are
controversial reported results whether graphene is really hydrophobic or hydrophilic. In order to
address this problem we have carried out classical molecular dynamics simulations of water
nanodroplets shot against graphene surface. Our results show that the contact angle values
between the nanodroplets and graphene surfaces depend on the initial droplet velocity value and
these angles can change from 86º (hydrophobic) to 35º (hydrophilic). Our preliminary results
indicate that the graphene wettability can be dependent on spreading liquid dynamics and which
can explain some of the apparent inconsistencies reported in the literature.
