http://scholar.google.com/citations?hl=en&user=95SvbM8AAAAJ
Chipara, A. C.; Tsafack, T.; Owuor, P. S.; Yeon, J.; Junkermeier, C. E.; van Duin, A. C. T.; Bhowmick, S.; Asif, S. A. S.; Radhakrishnan, S.; Park, J. H.; Brunetto, G.; Kaipparettu, B. A.; Galvão, D. S.; Chipara, M.; Lou, J.; Tsang, H. H.; Dubey, M.; Vajtai, R.; Tiwary, C. S.; Ajayan, P. M.
Underwater Adhesive using Solid–liquid Polymer Mixes Journal Article
Em: Materials Today Chemistry, vol. 9, pp. 149-157, 2018.
@article{Chipara2018,
title = {Underwater Adhesive using Solid–liquid Polymer Mixes},
author = {A.C. Chipara and T. Tsafack and P.S. Owuor and J. Yeon and C.E. Junkermeier and A.C.T. van Duin and S. Bhowmick and S.A.S. Asif and S. Radhakrishnan and J.H. Park and G. Brunetto and B.A. Kaipparettu and D.S. Galvão and M. Chipara and J. Lou and H.H. Tsang and M. Dubey and R. Vajtai and C.S. Tiwary and P.M. Ajayan},
url = {https://www.sciencedirect.com/science/article/pii/S2468519418301423#appsec1},
doi = {10.1016/j.mtchem.2018.07.002},
year = {2018},
date = {2018-08-08},
journal = {Materials Today Chemistry},
volume = {9},
pages = {149-157},
abstract = {Instantaneous adhesion between different materials is a requirement for several applications ranging from electronics to biomedicine. Approaches such as surface patterning, chemical cross-linking, surface modification, and chemical synthesis have been adopted to generate temporary adhesion between various materials and surfaces. Because of the lack of curing times, temporary adhesives are instantaneous, a useful property for specific applications that need quick bonding. However, to this day, temporary adhesives have been mainly demonstrated under dry conditions and do not work well in submerged or humid environments. Furthermore, most rely on chemical bonds resulting from strong interactions with the substrate such as acrylate based. This work demonstrates the synthesis of a universal amphibious adhesive solely by combining solid polytetrafluoroethylene (PTFE) and liquid polydimethylsiloxane (PDMS) polymers. While the dipole-dipole interactions are induced by a large electronegativity difference between fluorine atoms in PTFE and hydrogen atoms in PDMS, strong surface wetting allows the proposed adhesive to fully coat both substrates and PTFE particles, thereby maximizing the interfacial chemistry. The two-phase solid–liquid polymer system displays adhesive characteristics applicable both in air and water, and enables joining of a wide range of similar and dissimilar materials (glasses, metals, ceramics, papers, and biomaterials). The adhesive exhibits excellent mechanical properties for the joints between various surfaces as observed in lap shear testing, T-peel testing, and tensile testing. The proposed biocompatible adhesive can also be reused multiple times in different dry and wet environments. Additionally, we have developed a new reactive force field parameterization and used it in our molecular dynamics simulations to validate the adhesive nature of the mixed polymer system with different surfaces. This simple amphibious adhesive could meet the need for a universal glue that performs well with a number of materials for a wide range of conditions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Oliveira, Eliezer F.; Autreto, Pedro A. S.; Woellner, Cristiano F.; Galvao, Douglas S.
On the mechanical properties of novamene: a fully atomistic molecular dynamics and DFT investigation Journal Article
Em: Carbon, vol. 139, pp. 782-788, 2018.
@article{Oliveira2018e,
title = {On the mechanical properties of novamene: a fully atomistic molecular dynamics and DFT investigation},
author = {Eliezer F. Oliveira and Pedro A. S. Autreto and Cristiano F. Woellner and Douglas S. Galvao},
url = {https://www.sciencedirect.com/science/article/pii/S0008622318306882?via%3Dihub#appsec1},
doi = {10.1016/j.carbon.2018.07.038},
year = {2018},
date = {2018-07-19},
journal = {Carbon},
volume = {139},
pages = {782-788},
abstract = {We have investigated through fully atomistic reactive molecular dynamics and density functional theory simulations, the mechanical properties and fracture dynamics of single-ringed novamene (1R-novamene), a new 3D carbon allotrope structure recently proposed. Our results showed that 1R-novamene is an anisotropic structure with relation to tensile deformation. Although 1R-novamente shares some mechanical features with other carbon allotropes, it also exhibits distinct ones, such as, extensive structural reconstructions. 1R-novamene presents ultimate strength (∼100 GPa) values lower than other carbon allotropes, but it has the highest ultimate strain along the z-direction (∼22.5%). Although the Young's modulus (∼600 GPa) and ultimate strength values are smaller than for other carbon allotropes, they still outperform other materials, such as for example silicon, steel or titanium alloys. With relation to the fracture dynamics, 1R-novamene is again anisotropic with the fracture/crack propagation originating from deformed heptagons and pentagons for x and y directions and broken sp3 bonds connecting structural planes. Another interesting feature is the formation of multiple and long carbon linear chains in the final fracture stages.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gautam, Chandkiram; Chakravarty, Dibyendu; Woellner, Cristiano F.; Mishra, Vijay Kumar; Ahamad, Naseer; Gautam, Amarendra; Ozden, Sehmus; Jose, Sujin; Biradar, Santosh Kumar; Vajtai, Robert; Trivedi, Ritu; Tiwary, Chandra Sekhar; Galvao, Douglas S.; Ajayan, P. M.
Synthesis and 3D Interconnected Nanostructured h-BN-Based Biocomposites by Low-Temperature Plasma Sintering: Bone Regeneration Applications Journal Article
Em: ACS Omega, vol. 3, não 6, pp. 6013–6021, 2018.
@article{Gautam2018,
title = {Synthesis and 3D Interconnected Nanostructured h-BN-Based Biocomposites by Low-Temperature Plasma Sintering: Bone Regeneration Applications},
author = {Chandkiram Gautam and Dibyendu Chakravarty and Cristiano F. Woellner and Vijay Kumar Mishra and Naseer Ahamad and Amarendra Gautam and Sehmus Ozden and Sujin Jose and Santosh Kumar Biradar and Robert Vajtai and Ritu Trivedi and Chandra Sekhar Tiwary and Douglas S. Galvao and P.M. Ajayan},
url = {https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00707},
doi = {10.1021/acsomega.8b00707},
year = {2018},
date = {2018-06-05},
journal = {ACS Omega},
volume = {3},
number = {6},
pages = {6013–6021},
abstract = {Recent advances and demands in biomedical applications drive a large amount of research to synthesize easily scalable low-density, high-strength, and wear-resistant biomaterials. The chemical inertness with low density combined with high strength makes h-BN one of the promising materials for such application. In this work, three-dimensional hexagonal boron nitride (h-BN) interconnected with boron trioxide (B2O3) was prepared by easily scalable and energy efficient spark plasma sintering (SPS) process. The composite structure shows significant densification (1.6–1.9 g/cm3) and high surface area (0.97–14.5 m2/g) at an extremely low SPS temperature of 250 °C. A high compressive strength of 291 MPa with a reasonably good wear resistance was obtained for the composite structure. The formation of strong covalent bonds between h-BN and B2O3 was formulated and established by molecular dynamics simulation. The composite showed significant effect on cell viability/proliferation. It shows a high mineralized nodule formation over the control, which suggests its use as a possible osteogenic agent in bone formation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Balan, Aravind Puthirath; Radhakrishnan, Sruthi; Woellner, Cristiano F.; Sinha, Shyam K.; Deng, Liangzi; de los Reyes, Carlos; Rao, Manmadha; Paulose, Maggie; Neupane, Ram; Vajtai, Robert; Chu, Ching-Wu; Costin, Gelu; Galvao, Douglas S.; Marti, Angel A.; van Aken, Peter; Varghese, Oomman K; Tiwary, Chandra Sekhar; Anantharaman, M R; Ajayan, Pulickel M
Exfoliation of a non-van der Waals material from iron ore hematite Journal Article
Em: Nature Nanotechnology, vol. 13, pp. 602–610, 2018.
@article{Balan2018,
title = {Exfoliation of a non-van der Waals material from iron ore hematite},
author = {Aravind Puthirath Balan and Sruthi Radhakrishnan and Cristiano F. Woellner and Shyam K. Sinha and Liangzi Deng and Carlos de los Reyes and Manmadha Rao and Maggie Paulose and Ram Neupane and Robert Vajtai and Ching-Wu Chu and Gelu Costin and Douglas S. Galvao and Angel A. Marti and Peter van Aken and Oomman K Varghese and Chandra Sekhar Tiwary and M R Anantharaman and Pulickel M Ajayan
},
url = {https://www.nature.com/articles/s41565-018-0134-y},
year = {2018},
date = {2018-05-07},
journal = {Nature Nanotechnology},
volume = {13},
pages = {602--610},
abstract = {With the advent of graphene, the most studied of all two-dimensional materials, many inorganic analogues have been synthesized and are being exploited for novel applications. Several approaches have been used to obtain large-grain, high-quality materials. Naturally occurring ores, for example, are the best precursors for obtaining highly ordered and large-grain atomic layers by exfoliation. Here, we demonstrate a new two-dimensional material ‘hematene’ obtained from natural iron ore hematite (α-Fe2O3), which is isolated by means of liquid exfoliation. The two-dimensional morphology of hematene is confirmed by transmission electron microscopy. Magnetic measurements together with density functional theory calculations confirm the ferromagnetic order in hematene while its parent form exhibits antiferromagnetic order. When loaded on titania nanotube arrays, hematene exhibits enhanced visible light photocatalytic activity. Our study indicates that photogenerated electrons can be transferred from hematene to titania despite a band alignment unfavourable for charge transfer.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bizao, Rafael A; Machado, Leonardo D; de Sousa, Jose M; Pugno, Nicola M; Galvao, Douglas S
Scale Effects on the Ballistic Penetration of Graphene Sheets Journal Article
Em: Nature Scientific Reports, vol. 8, pp. 6750, 2018.
@article{Bizao2018,
title = {Scale Effects on the Ballistic Penetration of Graphene Sheets},
author = {Bizao, Rafael A and Machado, Leonardo D and de Sousa, Jose M and Pugno, Nicola M and Galvao, Douglas S},
url = {https://www.nature.com/articles/s41598-018-25050-2},
doi = {doi:10.1038/s41598-018-25050-2},
year = {2018},
date = {2018-04-30},
journal = {Nature Scientific Reports},
volume = {8},
pages = {6750},
abstract = {Carbon nanostructures are promising ballistic protection materials, due to their low density and excellent mechanical properties. Recent experimental and computational investigations on the behavior of graphene under impact conditions revealed exceptional energy absorption properties as well. However, the reported numerical and experimental values differ by an order of magnitude. In this work, we combined numerical and analytical modeling to address this issue. In the numerical part, we employed reactive molecular dynamics to carry out ballistic tests on single, double, and triple-layered graphene sheets. We used velocity values within the range tested in experiments. Our numerical and the experimental results were used to determine parameters for a scaling law. We find that the specific penetration energy decreases as the number of layers (N) increases, from ∼15 MJ/kg for N = 1 to ∼0.9 MJ/kg for N = 350, for an impact velocity of 900 m/s. These values are in good agreement with simulations and experiments, within the entire range of N values for which data is presently available. Scale effects explain the apparent discrepancy between simulations and experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Marco AE Maria Celina M Miyazaki, Daiane Damasceno Borges
Experimental and computational investigation of reduced graphene oxide nanoplatelets stabilized in poly(styrene sulfonate) sodium salt Journal Article
Em: Journal of Materials Science, vol. 53, não 14, pp. 10049-10056, 2018.
@article{Miyazaki2018,
title = {Experimental and computational investigation of reduced graphene oxide nanoplatelets stabilized in poly(styrene sulfonate) sodium salt},
author = {Celina M Miyazaki, Marco AE Maria, Daiane Damasceno Borges, Cristiano F Woellner, Gustavo Brunetto, Alexandre F Fonseca, Carlos JL Constantino, Marcelo A Pereira-da-Silva, Abner de Siervo, Douglas S Galvao, Antonio Riul Jr},
url = {https://link.springer.com/article/10.1007/s10853-018-2325-1},
doi = {https://link.springer.com/article/10.1007/s10853-018-2325-1},
year = {2018},
date = {2018-04-19},
journal = {Journal of Materials Science},
volume = {53},
number = {14},
pages = {10049-10056},
abstract = {The production of large-area interfaces and the use of scalable methods to build up
designed nanostructures generating advanced functional properties are of high
interest for many materials science applications. Nevertheless, large-area coverage
remains a major problem even for pristine graphene, and here we present a hybrid,
composite graphene-like material soluble in water that can be exploited in many
areas such as energy storage, electrodes fabrication, selective membranes and
biosensing. Graphene oxide (GO) was produced by the traditional Hummers’
method being further reduced in the presence of poly(styrene sulfonate) sodium salt
(PSS), thus creating stable reduced graphene oxide (rGO) nanoplatelets wrapped by
PSS (GPSS). Molecular dynamics simulations were carried out to further clarify the
interactions between PSS molecules and rGO nanoplatelets, with calculations
supported by Fourier transform infrared spectroscopy analysis. The intermolecular
forces between rGO nanoplatelets and PSS lead to the formation of a hybrid material
(GPSS) stabilized by van der Waals forces, allowing the fabrication of high-quality
layer-by-layer (LbL) films with poly(allylamine hydrochloride) (PAH). Raman and
electrical characterizations corroborated the successful modifications in the electronic
structures from GO to GPSS after the chemical treatment, resulting in (PAH/
GPSS) LbL films four orders of magnitude more conductive than (PAH/GO).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
designed nanostructures generating advanced functional properties are of high
interest for many materials science applications. Nevertheless, large-area coverage
remains a major problem even for pristine graphene, and here we present a hybrid,
composite graphene-like material soluble in water that can be exploited in many
areas such as energy storage, electrodes fabrication, selective membranes and
biosensing. Graphene oxide (GO) was produced by the traditional Hummers’
method being further reduced in the presence of poly(styrene sulfonate) sodium salt
(PSS), thus creating stable reduced graphene oxide (rGO) nanoplatelets wrapped by
PSS (GPSS). Molecular dynamics simulations were carried out to further clarify the
interactions between PSS molecules and rGO nanoplatelets, with calculations
supported by Fourier transform infrared spectroscopy analysis. The intermolecular
forces between rGO nanoplatelets and PSS lead to the formation of a hybrid material
(GPSS) stabilized by van der Waals forces, allowing the fabrication of high-quality
layer-by-layer (LbL) films with poly(allylamine hydrochloride) (PAH). Raman and
electrical characterizations corroborated the successful modifications in the electronic
structures from GO to GPSS after the chemical treatment, resulting in (PAH/
GPSS) LbL films four orders of magnitude more conductive than (PAH/GO).
Eliezer F.; Autreto Oliveira, Pedro A. S. ; Woellner
On the mechanical properties of novamene: a fully atomistic molecular dynamics and DFT investigation Online
2018, (preprint ArXiv:1804.07215).
@online{Oliveira2018f,
title = {On the mechanical properties of novamene: a fully atomistic molecular dynamics and DFT investigation},
author = {Oliveira, Eliezer F.; Autreto, Pedro A. S.; Woellner, Cristiano F.; Galvao, Douglas S.},
url = {https://arxiv.org/abs/1804.07215},
year = {2018},
date = {2018-04-19},
abstract = {We have investigated through fully atomistic reactive molecular dynamics and DFT simulations, the mechanical properties and fracture dynamics of novamene, a new 3D carbon allotrope structure recently proposed. Our results showed that novamene is an anisotropic structure with relation to tensile deformation. Although novamente shares some mechanical features with other carbon allotropes, it also exhibits distinct ones, such as, extensive structural reconstructions (self-healing effect). Novamene presents ultimate strength (~ 100 GPa) values lower than other carbon allotropes, but it has the highest ultimate strain along the z-direction (~ 22.5%). Although the Young's modulus (~ 600 GPa) and ultimate strength values are smaller than for other carbon allotropes, they still outperform other materials, such as for example silicon, steel or titanium alloys. With relation to the fracture dynamics, novamene is again anisotropic with the fracture/crack propagation originating from deformed heptagons and pentagons for x and y directions and broken sp3 bonds connecting structural planes. Another interesting feature is the formation of multiple and long carbon linear chains in the final fracture stages.},
note = {preprint ArXiv:1804.07215},
keywords = {},
pubstate = {published},
tppubtype = {online}
}
Kabbani, Mohamad A.; Kochat, Vidya; Bhowmick, Sanjit; Soto, Matias; Som, Anirban; Krishnadas, K. R.; Woellner, Cristiano F.; Jaques, Ygor M.; Barrera, Enrique V.; Asif, Syed; Vajtai, Robert; Pradeep, Thalappil; Galvão, Douglas S.; Kabbani, Ahmad T.; Tiwary, Chandra Sekhar; Ajayan, Pulickel M.
Consolidation of Functionalized Graphene at Ambient Temperature via Mechano-chemistry Journal Article
Em: Carbon, vol. 134, não 8, pp. 491-499, 2018.
@article{Kabbani2018,
title = {Consolidation of Functionalized Graphene at Ambient Temperature via Mechano-chemistry},
author = {Mohamad A. Kabbani and Vidya Kochat and Sanjit Bhowmick and Matias Soto and Anirban Som and K.R. Krishnadas and Cristiano F. Woellner and Ygor M. Jaques and Enrique V. Barrera and Syed Asif and Robert Vajtai and Thalappil Pradeep and Douglas S. Galvão and Ahmad T. Kabbani and Chandra Sekhar Tiwary and Pulickel M. Ajayan},
url = {https://www.sciencedirect.com/science/article/pii/S0008622318302987?dgcid=raven_sd_aip_email},
doi = {DOI:10.1016/j.carbon.2018.03.049},
year = {2018},
date = {2018-03-22},
journal = {Carbon},
volume = {134},
number = {8},
pages = {491-499},
abstract = {Graphitic solids are typically produced via high temperature and energy consuming
processing (e.g. sintering) of carbon particles. Here, we demonstrate the mechano-chemical
assembly of functionalized graphene layers into 3D graphitic solids via room temperature and
low energy consuming processing. The chemical functional groups on graphene layers are
interconnected at room temperature under pressure leading to porous three-dimensional
structures with tunable mechanical and electrical properties. The formation of mechanochemistry
induced atomic scale junctions and their impact on mechanical properties of
graphene assembled carbon materials are demonstrated through nano-indentation experiments
and confirmed using DFT and molecular dynamics simulations. The results show room
temperature consolidation routes of graphene layers into bulk carbon solids.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
processing (e.g. sintering) of carbon particles. Here, we demonstrate the mechano-chemical
assembly of functionalized graphene layers into 3D graphitic solids via room temperature and
low energy consuming processing. The chemical functional groups on graphene layers are
interconnected at room temperature under pressure leading to porous three-dimensional
structures with tunable mechanical and electrical properties. The formation of mechanochemistry
induced atomic scale junctions and their impact on mechanical properties of
graphene assembled carbon materials are demonstrated through nano-indentation experiments
and confirmed using DFT and molecular dynamics simulations. The results show room
temperature consolidation routes of graphene layers into bulk carbon solids.
Zink, Stefan; Moura, Francisco Alirio; da Silva Autreto, Pedro Alves; Galvao, Douglas Soares; Mizaikoff, Boris
Virtually Imprinted Polymers (VIPs): Understanding Molecularly Templated Materials via Molecular Dynamics Simulations Journal Article
Em: Physical Chemistry Chemical Physics, vol. 20, pp. 13145-13152, 2018.
@article{Zink2018b,
title = {Virtually Imprinted Polymers (VIPs): Understanding Molecularly Templated Materials via Molecular Dynamics Simulations},
author = {Stefan Zink and Francisco Alirio Moura and Pedro Alves da Silva Autreto and Douglas Soares Galvao and Boris Mizaikoff},
url = {http://pubs.rsc.org/en/content/articlelanding/2018/cp/c7cp08284c/unauth#!divAbstract},
doi = {10.1039/C7CP08284C},
year = {2018},
date = {2018-02-15},
journal = {Physical Chemistry Chemical Physics},
volume = {20},
pages = {13145-13152},
abstract = {Molecularly imprinted polymers are advanced recognition materials selectively rebinding a target molecule present during synthesis of the polymer matrix. It is commonly understood that the templating process is based on embedding the complex formed between a template and functional monomers into a co-polymer matrix via polymerization with a cross-linker while maintaining their spatial arrangement forming a molecular imprint. Template removal then leads to synthetic recognition sites ready to selectively rebind their targets, which are complementary in functionality, size and shape to the target. In this study, an innovative theoretical concept using fully atomistic molecular dynamics simulations for modeling molecular templating processes is introduced yielding virtually imprinted polymers (VIPs). VIPs created for the template of 17-beta-estradiol and applied in modeled chromatography experiments demonstrated selectivity for their template evidencing the creation of virtual imprints as a result of a template synthesis protocol, which represents a theoretical confirmation of the governing imprinting theory.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Leonardo D Machado Cristiano F Woellner, Pedro AS Autreto; Galvao, Douglas S
Structural Transformations of Carbon and Boron Nitride Nanoscrolls at High Impact Collisions Journal Article
Em: Physical Chemistry Chemical Physics, vol. 20, pp. 4911-4916, 2018.
@article{Woellner2018,
title = {Structural Transformations of Carbon and Boron Nitride Nanoscrolls at High Impact Collisions},
author = {Cristiano F Woellner, Leonardo D Machado, Pedro AS Autreto, Jose M de Sousa, and Douglas S Galvao},
url = {http://pubs.rsc.org/en/content/articlelanding/2018/cp/c7cp07402f#!divAbstract},
doi = {DOI:10.1039/C7CP07402F},
year = {2018},
date = {2018-02-14},
journal = {Physical Chemistry Chemical Physics},
volume = {20},
pages = {4911-4916},
abstract = {The behavior of nanostructures under high strain-rate conditions has been the object of theoretical and
experimental investigations in recent years. For instance, it has been shown that carbon and boron
nitride nanotubes can be unzipped into nanoribbons at high-velocity impacts. However, the response of
many nanostructures to high strain-rate conditions is still unknown. In this work, we have investigated
the mechanical behavior of carbon (CNS) and boron nitride nanoscrolls (BNS) colliding against solid
targets at high velocities, using fully atomistic reactive (ReaxFF) molecular dynamics (MD) simulations.
CNS (BNS) are graphene (boron nitride) membranes rolled up into papyrus-like structures. Their openended
topology leads to unique properties not found in their close-ended analogs, such as nanotubes.
Our results show that collision products are mainly determined by impact velocities and by two
orientation angles, which define the position of the scroll (i) axis and (ii) open edge relative to the target.
Our MD results showed that for appropriate velocities and orientations, large-scale deformations and
nanoscroll fractures could occur. We also observed unscrolling (scrolls going back to quasi-planar
membranes), scroll unzipping into nanoribbons, and significant reconstruction due to breaking and/or
formation of new chemical bonds. For particular edge orientations and velocities, conversion from open
to close-ended topology is also possible, due to the fusion of nanoscroll walls.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
experimental investigations in recent years. For instance, it has been shown that carbon and boron
nitride nanotubes can be unzipped into nanoribbons at high-velocity impacts. However, the response of
many nanostructures to high strain-rate conditions is still unknown. In this work, we have investigated
the mechanical behavior of carbon (CNS) and boron nitride nanoscrolls (BNS) colliding against solid
targets at high velocities, using fully atomistic reactive (ReaxFF) molecular dynamics (MD) simulations.
CNS (BNS) are graphene (boron nitride) membranes rolled up into papyrus-like structures. Their openended
topology leads to unique properties not found in their close-ended analogs, such as nanotubes.
Our results show that collision products are mainly determined by impact velocities and by two
orientation angles, which define the position of the scroll (i) axis and (ii) open edge relative to the target.
Our MD results showed that for appropriate velocities and orientations, large-scale deformations and
nanoscroll fractures could occur. We also observed unscrolling (scrolls going back to quasi-planar
membranes), scroll unzipping into nanoribbons, and significant reconstruction due to breaking and/or
formation of new chemical bonds. For particular edge orientations and velocities, conversion from open
to close-ended topology is also possible, due to the fusion of nanoscroll walls.
Borges, Daiane Damasceno; Galvao, Douglas S.
Schwarzites for Natural Gas Storage: A Grand-Canonical Monte Carlo Study Journal Article
Em: MRS Advances, vol. 3, não 1-2, pp. 115-120, 2018.
@article{Borges2018d,
title = {Schwarzites for Natural Gas Storage: A Grand-Canonical Monte Carlo Study },
author = {Daiane Damasceno Borges and Douglas S. Galvao},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/schwarzites-for-natural-gas-storage-a-grandcanonical-monte-carlo-study/2DF8D601AF8EF04BBAC5CCCBEFA8339E},
doi = {https://doi.org/10.1557/adv.2018.190},
year = {2018},
date = {2018-02-13},
journal = {MRS Advances},
volume = {3},
number = {1-2},
pages = {115-120},
abstract = {he 3D porous carbon-based structures called Schwarzites have been recently a subject of renewed interest due to the possibility of being synthesized in the near future. These structures exhibit negatively curvature topologies with tuneable porous sizes and shapes, which make them natural candidates for applications such as CO2 capture, gas storage and separation. Nevertheless, the adsorption properties of these materials have not been fully investigated. Following this motivation, we have carried out Grand-Canonical Monte Carlo simulations to study the adsorption of small molecules such as CO2, CO, CH4, N2 and H2, in a series of Schwarzites structures. Here, we present our preliminary results on natural gas adsorptive capacity in association with analyses of the guest-host interaction strengths. Our results show that Schwarzites P7par, P8bal and IWPg are the most promising structures with very high CO2 and CH4 adsorption capacity and low saturation pressure (<1bar) at ambient temperature. The P688 is interesting for H2 storage due to its exceptional high H2 adsorption enthalpy value of -19kJ/mol.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Borges, Daiane Damasceno; Woellner, Cristiano F.; Autreto, Pedro A. S.; Galvao, Douglas S.
Water/alcohol separation via layered oxide graphene membranes Journal Article
Em: MRS Advances, vol. 3, não 1-2, pp. 109-114, 2018.
@article{Borges2018d,
title = {Water/alcohol separation via layered oxide graphene membranes},
author = {Daiane Damasceno Borges and Cristiano F. Woellner and Pedro A. S. Autreto and Douglas S. Galvao},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/wateralcohol-separation-in-graphene-oxide-membranes-insights-from-molecular-dynamics-and-monte-carlo-simulations/C61C66FF48D35EB2DB3408ACCE96C41A},
doi = { https://doi.org/10.1557/adv.2018.192},
year = {2018},
date = {2018-02-13},
journal = {MRS Advances},
volume = {3},
number = {1-2},
pages = {109-114},
abstract = {Graphene-based membranes have been investigated as promising candidates for water filtration and gas separation applications. Experimental evidences have shown that graphene oxide can be impermeable to liquids, vapors and gases, while allowing a fast permeation of water molecules. This phenomenon has been attributed to the formation of a network of nano capillaries that allow nearly frictionless water flow while blocking other molecules by steric hindrance effects. It is supposed that water molecules are transported through the percolated two-dimensional channels formed between graphene-based sheets. Although these channels allow fast water permeation in such materials, the flow rates are strongly dependent on how the membranes are fabricated. Also, some fundamental issues regarding the nanoscale mechanisms of water permeation are still not fully understood and their interpretation remains controversial. In this work, we have investigated the dynamics of water permeation through pristine graphene and graphene oxide model membranes that have strong impact on water/alcohol separation. We have carried out fully atomistic classical molecular dynamics simulations of systems composed of multiple layered graphene-based sheets into contact with a pure water reservoir under controlled thermodynamics conditions (e. g., by varying temperature and pressure values). We have systematically analysed how the transport dynamics of the confined nanofluids depend on the interlayer distances and the role of the oxide functional groups. Our results show the water flux is much more effective for graphene than for graphene oxide membranes. These results can be attributed to the H-bonds formation between oxide functional groups and water, which traps the water molecules and precludes ultrafast water transport through the nanochannels.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Oliveira, Eliezer Fernando; Autreto, Pedro Alves da Silva; Galvao, Douglas Soares
On hardening silver nanocubes by high velocity impacts: a fully atomistic molecular dynamics investigation Journal Article
Em: Journal of Materials Science, vol. 53, não 10, pp. 7486–7492, 2018.
@article{Oliveira2018,
title = {On hardening silver nanocubes by high velocity impacts: a fully atomistic molecular dynamics investigation},
author = {Oliveira, Eliezer Fernando and Autreto, Pedro Alves da Silva and Galvao, Douglas Soares},
url = {https://link.springer.com/article/10.1007/s10853-018-2104-z},
doi = {10.1007/s10853-018-2104-z},
year = {2018},
date = {2018-02-09},
journal = {Journal of Materials Science},
volume = {53},
number = {10},
pages = {7486–7492},
abstract = {Gradient nanograins (GNG) creation in metals has been a promising approach to obtain ultra-strong materials. Recently, R. Thevamaran et al. (Science 354:312 in 2016) proposed a single-step method based on high-velocity impacts of silver nanocubes (SNC) to produce almost perfect GNG. However, after certain time, these grains spontaneously coalesce, which compromises the induced hardening and other mechanical properties. To better understand these processes, a detailed investigation at the atomic scale of the deformation/hardening mechanisms are needed, which is one of the objectives of the present work. We carried out fully atomistic molecular dynamics (MD) simulations of silver nanocubes at high impact velocity values using realistic structural models. Our MD results suggest that besides the GNG mechanisms, the observed SNC hardening could be also the result of the existence of polycrystalline arrangements formed by HCP domains encapsulated by FCC ones in the smashed SNC. This can be a new way to design ultra-strong materials, even in the absence of GNG domains.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
de Sousa, J. M.; Aguiar, A. L.; Girao, E. C.; Fonseca, Alexandre F.; Filho, A. G. Souza; Galvao, Douglas S.
Mechanical Properties of Pentagraphene-based Nanotubes: A Molecular Dynamics Study Journal Article
Em: MRS Advances, vol. 3, não 1-2, pp. 97-102, 2018.
@article{deSousa2018b,
title = {Mechanical Properties of Pentagraphene-based Nanotubes: A Molecular Dynamics Study},
author = {J. M. de Sousa and A. L. Aguiar and E. C. Girao and Alexandre F. Fonseca and A. G. Souza Filho and Douglas S. Galvao},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/mechanical-properties-of-pentagraphenebased-nanotubes-a-molecular-dynamics-study/289AB70DADF20059BB8FCC9EF07B97AB},
doi = { https://doi.org/10.1557/adv.2018.160},
year = {2018},
date = {2018-02-06},
journal = {MRS Advances},
volume = {3},
number = {1-2},
pages = {97-102},
abstract = {The study of the mechanical properties of nanostructured systems has gained importance in theoretical and experimental research in recent years. Carbon nanotubes (CNTs) are one of the strongest nanomaterials found in nature, with Young’s Modulus (EY) in the order 1.25 TPa. One interesting question is about the possibility of generating new nanostructures with 1D symmetry and with similar and/or superior CNT properties. In this work, we present a study on the dynamical, structural, mechanical properties, fracture patterns and EY values for one class of these structures, the so-called pentagraphene nanotubes (PGNTs). These tubes are formed rolling up pentagraphene membranes (which are quasi-bidimensional structures formed by densely compacted pentagons of carbon atoms in sp3 and sp2 hybridized states) in the same form that CNTs are formed from rolling up graphene membranes. We carried out fully atomistic molecular dynamics simulations using the ReaxFF force field. We have considered zigzag-like and armchair-like PGNTs of different diameters. Our results show that PGNTs present EY ∼ 800 GPa with distinct elastic behavior in relation to CNTs, mainly associated with mechanical failure, chirality dependent fracture patterns and extensive structural reconstructions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cristiano F Woellner Daiane Damasceno Borges, Pedro AS Autreto
Insights on the mechanism of water-alcohol separation in multilayer graphene oxide membranes: entropic versus enthalpic factors Journal Article
Em: Carbon, vol. 127, pp. 280-286, 2018.
@article{Borges2018,
title = {Insights on the mechanism of water-alcohol separation in multilayer graphene oxide membranes: entropic versus enthalpic factors},
author = {Daiane Damasceno Borges, Cristiano F Woellner, Pedro AS Autreto, Douglas S Galvao},
url = {https://www.sciencedirect.com/science/article/pii/S000862231731134X},
doi = {https://doi.org/10.1016/j.carbon.2017.11.020},
year = {2018},
date = {2018-02-01},
journal = {Carbon},
volume = {127},
pages = {280-286},
abstract = {xperimental evidence has shown that graphene oxide (GO) can be impermeable to liquids, vapors and gases, while it allows a fast permeation of water molecules. Theoretical studies to understand the filtration mechanisms come mostly from water desalination, while very few works have been dedicated to alcohol dehydration. In this work, we have investigated the molecular level mechanism underlying the alcohol/water separation inside GO membranes. A series of Molecular Dynamics and Grand-Canonical Monte Carlo simulations were carried out to probe the ethanol/water and methanol/water separation through GO membranes composed of multiple layered graphene-based films with different interlayer distance values and number of oxygen-containing functional groups. Our results show that the size exclusion and membrane affinities are not sufficient to explain the selectivity. Besides that, the favorable water molecular arrangement inside GO 2D-channels forming a robust H-bond network and the fast water permeation are crucial for an effective separation mechanism. In other words, the separation phenomenon is not only governed by membrane affinities (enthalpic mechanisms) but mainly by the geometry and size factors (entropic mechanisms). Our findings are consistent with the available experimental data and contribute to clarify important aspects of the separation behavior of confined alcohol/water in GO membranes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fonseca, Alexandre F.; Galvao, Douglas S.
Self-Driven Graphene Tearing and Peeling: A Fully Atomistic Molecular Dynamics Investigation Journal Article
Em: MRS Advances, vol. 3, não 8-9, pp. 460-465, 2018.
@article{Fonseca2018,
title = {Self-Driven Graphene Tearing and Peeling: A Fully Atomistic Molecular Dynamics Investigation},
author = {Alexandre F. Fonseca and Douglas S. Galvao},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/selfdriven-graphene-tearing-and-peeling-a-fully-atomistic-molecular-dynamics-investigation/BFC76FC4479AA617E16FA6AC7AB4D487},
doi = {https://doi.org/10.1557/adv.2018.120},
year = {2018},
date = {2018-01-30},
journal = {MRS Advances},
volume = {3},
number = {8-9},
pages = {460-465},
abstract = {In 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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Woellner, Cristiano F.; Botari, Tiago; Perim, Eric; Galvao, Douglas S.
Mechanical Properties of Schwarzites - A Fully Atomistic Reactive Molecular Dynamics Investigation Journal Article
Em: MRS Advances, pp. 1-6, 2018.
@article{Woellner2018b,
title = {Mechanical Properties of Schwarzites - A Fully Atomistic Reactive Molecular Dynamics Investigation},
author = {Cristiano F. Woellner and Tiago Botari and Eric Perim and Douglas S. Galvao},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/mechanical-properties-of-schwarzites-a-fully-atomistic-reactive-molecular-dynamics-investigation/012AF477491A46541A052C944E4E4834},
doi = { https://doi.org/10.1557/adv.2018.124},
year = {2018},
date = {2018-01-29},
journal = {MRS Advances},
pages = {1-6},
abstract = {Schwarzites are crystalline, 3D porous structures with a stable negative curvature formed of sp2-hybridized carbon atoms. These structures present topologies with tunable porous size and shape and unusual mechanical properties. In this work, we have investigated the mechanical behavior under compressive strain and energy absorption of four different Schwarzites. We considered two Schwarzites families, the so-called Gyroid and Primitive and two structures from each family. We carried out reactive molecular dynamics simulations, using the ReaxFF force field as available in the LAMMPS code. Our results also show they exhibit remarkable resilience under mechanical compression. They can be reduced to half of their original size before structural failure (fracture) occurs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Woellner, Cristiano F.; Owuor, Peter S.; Li, Tong; Vinod, Soumya; Ozden, Sehmus; Kosolwattana, Suppanat; Bhowmick, Sanjit; Duy, Luong X.; Salvatierra, Rodrigo V.; Wei, Bingqing; Asif, Syed A. S.; Tour, James M.; Vajtai, Robert; Lou, Jun; Galvão, Douglas S.; Tiwary, Chandra S.; Ajayan, Pulickel. M.
Mechanical Properties of Ultralow Density Graphene Oxide/Polydimethylsiloxane Foams Journal Article
Em: MRS Advances, vol. 3, não 1-2, pp. 61-66, 2018.
@article{Woellner2018c,
title = {Mechanical Properties of Ultralow Density Graphene Oxide/Polydimethylsiloxane Foams},
author = {Cristiano F. Woellner and Peter S. Owuor and Tong Li and Soumya Vinod and Sehmus Ozden and Suppanat Kosolwattana and Sanjit Bhowmick and Luong X. Duy and Rodrigo V. Salvatierra and Bingqing Wei and Syed A. S. Asif and James M. Tour and Robert Vajtai and Jun Lou and Douglas S. Galvão and Chandra S. Tiwary and Pulickel. M. Ajayan},
url = {https://www.cambridge.org/core/journals/mrs-advances/article/mechanical-properties-of-ultralow-density-graphene-oxidepolydimethylsiloxane-foams/BC2DC24B3DB5714759FC1EDC71BD9D05},
doi = {DOI: 10.1557/adv.2018. 49},
year = {2018},
date = {2018-01-18},
journal = {MRS Advances},
volume = {3},
number = {1-2},
pages = { 61-66},
abstract = {Low-density, highly porous graphene/graphene oxide (GO) based-foams have shown high performance in energy absorption applications, even under high compressive deformations. In general, foams are very effective as energy dissipative materials and have been widely used in many areas such as automotive, aerospace and biomedical industries. In the case of graphene-based foams, the good mechanical properties are mainly attributed to the intrinsic graphene and/or GO electronic and mechanical properties. Despite the attractive physical properties of graphene/GO based-foams, their structural and thermal stabilities are still a problem for some applications. For instance, they are easily degraded when placed in flowing solutions, either by the collapsing of their layers or just by structural disintegration into small pieces. Recently, a new and scalable synthetic approach to produce low-density 3D macroscopic GO structure interconnected with polydimethylsiloxane (PDMS) polymeric chains (pGO) was proposed. A controlled amount of PDMS is infused into the freeze-dried foam resulting into a very rigid structure with improved mechanical properties, such as tensile plasticity and toughness. The PDMS wets the graphene oxide sheets and acts like a glue bonding PDMS and GO sheets. In order to obtain further insights on mechanisms behind the enhanced mechanical pGO response we carried out fully atomistic molecular dynamics (MD) simulations. Based on MD results, we build up a structural model that can explain the experimentally observed mechanical behavior.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Azevedo, David L.; Bizao, Rafael A.; Galvao, Douglas S.
Molecular Dynamics Simulations of Ballistic Penetration of Pentagraphene Sheets Online
2018, (preprint arXiv:1801.05346).
@online{Azevedo2018b,
title = {Molecular Dynamics Simulations of Ballistic Penetration of Pentagraphene Sheets},
author = {David L. Azevedo and Rafael A. Bizao and Douglas S. Galvao},
url = {https://arxiv.org/abs/1801.05346},
year = {2018},
date = {2018-01-18},
abstract = {The superior mechanical properties and low density of carbon nanostructures make them promising ballistic protection materials, stimulating investigations on their high-strain-rate behavior. Recent experiments and simulations revealed graphene possesses exceptional energy absorption properties. In this work, we analyzed through fully atomistic molecular dynamics simulations the ballistic performance of a carbon-based material recently proposed named penta-graphene. Our results show that the fracture pattern is more spherical (no petals formation like observed for graphene). The estimated penetration energy for pentagraphene structures considered here was of 37.69 MJ/Kg, far superior to graphene (29.8 MJ/Kg) under same conditions. These preliminary results are suggestive that pentagraphene could be an excellent material for ballistic applications.},
note = {preprint arXiv:1801.05346},
keywords = {},
pubstate = {published},
tppubtype = {online}
}
Woellner, Cristiano F.; Botari, Tiago; Perim, Eric; Galvao, Douglas S.
Mechanical Properties of Schwarzites - A Fully Atomistic Reactive Molecular Dynamics Investigation Online
2018, (preprint arXiv:1801.05639).
@online{Woellner2018d,
title = {Mechanical Properties of Schwarzites - A Fully Atomistic Reactive Molecular Dynamics Investigation},
author = {Cristiano F. Woellner and Tiago Botari and Eric Perim and Douglas S. Galvao},
url = {https://arxiv.org/abs/1801.05639},
year = {2018},
date = {2018-01-18},
abstract = {Schwarzites are crystalline, 3D porous structures with stable negative curvature formed of sp2-hybridized carbon atoms. These structures present topologies with tunable porous size and shape and unusual mechanical properties. In this work, we have investigated the mechanical behavior under compressive strains and energy absorption of four different Schwarzites, through reactive molecular dynamics simulations, using the ReaxFF force field as available in the LAMMPS code. We considered two Schwarzites families, the so-called Gyroid and Primitive and two structures from each family. Our results also show they exhibit remarkable resilience under mechanical compression. They can be reduced to half of their original size before structural failure (fracture) occurs.},
note = {preprint arXiv:1801.05639},
keywords = {},
pubstate = {published},
tppubtype = {online}
}
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