1. | Jaques, Ygor M; Galvao, Douglas S: Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted). In: Journal of Molecular Liquids, 2019. (Type: Journal Article | Abstract | BibTeX) @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. | Jaques Ygor M.; Galvao, Douglas S: Structural Properties of Nanodroplets Impacting Graphene at High Velocities. 2018, (Preprint ArXiv:1804.07784). (Type: Online | Abstract | Links | BibTeX) @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. |
2019 |
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2. | ![]() | Jaques, Ygor M; Galvao, Douglas S Structural Properties of Nanodroplets Impacting Graphene at High Velocities (accepted) Journal Article Journal of Molecular Liquids, 2019. Abstract | 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 |
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1. | ![]() | Jaques Ygor M.; Galvao, Douglas S Structural Properties of Nanodroplets Impacting Graphene at High Velocities Online 2018, (Preprint ArXiv:1804.07784). Abstract | 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. |
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