Ronaldo. J. C. Batista

2020
R. J. C. Batista, et al., “Nanomechanics of few-layer materials: do individual layers slide upon folding?,” Beilstein J. Nanotechnol., vol. 11, pp. 1801–1808, 2020.
L. G. P. Martins, et al., “Hard, transparent, sp3-containing 2D phase formed from few-layer graphene under compression,” Carbon, 2020. Publisher's VersionAbstract
Despite several theoretically proposed two-dimensional (2D) diamond structures, experimental efforts to obtain such structures are in initial stage. Recent high-pressure experiments provided significant advancements in the field, however, expected properties of a 2D-like diamond such as sp3 content, transparency and hardness, have not been observed together in a compressed graphene system. Here, we compress few-layer graphene samples on SiO2/Si substrate in water and provide experimental evidence for the formation of a quenchable hard, transparent, sp3-containing 2D phase. Our Raman spectroscopy data indicates phase transition and a surprisingly similar critical pressure for two-, five-layer graphene and graphite in the 4-6 GPa range, as evidenced by changes in several Raman features, combined with a lack of evidence of significant pressure gradients or local non-hydrostatic stress components of the pressure medium up to ≈ 8 GPa. The new phase is transparent and hard, as evidenced from indentation marks on the SiO2 substrate, a material considerably harder than graphene systems. Furthermore, we report the lowest critical pressure (≈ 4 GPa) in graphite, which we attribute to the role of water in facilitating the phase transition. Theoretical calculations and experimental data indicate a novel, surface-to-bulk phase transition mechanism that gives hint of diamondene formation.
L. M. Mota, et al., “Soapstone reinforced hydroxyapatite coatings for biomedical applications,” Surface and Coatings Technology, vol. 397, pp. 126005, 2020. Publisher's VersionAbstract
Mechanical resistant bioactive materials are of high interest for biomedical applications. In this work, we address the improvement in mechanical properties of HA coatings by the addition of a cheap and widely available secondary phase material, the talc from soapstone. The composites hydroxyapatite/talc (HA/talc) were successfully obtained by pulsed electrodeposition and characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, corrosion and wear resistance and biocompatibility tests. We found that the addition of talc greatly improves the mechanical properties of coatings (i. e., wear track and friction coefficient in wear tests were significantly diminished) without diminishing corrosion resistance and biocompatibility. Alamar Blue® tests, alkaline phosphatase activity, and collagen production indicate that the biocomposites are biocompatible and talc itself induce bone maturation.
2019
B. H. S. Mendonça, D. N. de Freitas, M. H. Köhler, R. J. C. Batista, M. C. Barbosa, and A. B. de Oliveira, “Diffusion behaviour of water confined in deformed carbon nanotubes,” Physica A: Statistical Mechanics and its Applications, vol. 517, pp. 491 - 498, 2019. Publisher's VersionAbstract
We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of eccentricity at 300 K. We found a water structural transition between tubular-like to single-file for (7,7) nanotubes associated with change from a high to low mobility regimes. Water is frozen when confined in a perfect (9,9) nanotube and it becomes liquid if such a nanotube is deformed above a certain threshold. Water diffusion enhancement (suppression) is related to a reduction (increase) in the number of hydrogen bonds. This suggests that the shape of the nanotube is an important ingredient when considering the dynamical and structural properties of confined water.
R. F. Dias, et al., “Ab initio molecular dynamics simulation of methanol and acetonitrile: The effect of van der Waals interactions,” Chemical Physics Letters, vol. 714, pp. 172 - 177, 2019. Publisher's VersionAbstract
We employed PBE and BLYP semi-local functionals and the van der Waals density functional of Dion et al. (2004) (vdW-DF) to investigate structural properties of liquid acetonitrile and methanol. Among those functionals the vdW-DF is the only one that correctly predicts energy minima in inter-molecular interactions between acetonitrile molecules. We found that van der Waals interactions have a negligible effect on H-bonds in methanol chains. However, it significantly increases chain packing resulting in a more dense liquid in comparison to the other two functionals. The overall trend is that the vdW-DF tends to overestimate density and bulk modulus, meanwhile the semi-local functionals tend to underestimate density. Thus, van der Waals interactions play an important role in the properties of liquids in which much stronger dipole-dipole interactions are present.
2018
E. P. F. Nhavene, et al., “Chitosan grafted into mesoporous silica nanoparticles as benznidazol carrier for Chagas diseases treatment,” Microporous and Mesoporous Materials, vol. 272, pp. 265 - 275, 2018. Publisher's VersionAbstract
The use of chitosan functionalized silica for benznidazole delivery in the treatment of neglected disease such as Chagas disease is one of the forms not yet explored, but with great potential for this therapy, as little is known about nanoformulations for the treatment of Chagas disease. In this work, we used chitosan-succinate covalently attached to the surface pore of MSNs to act as anchor for benznidazole as a delivery system. The samples were characterized structurally and chemically with multiple techniques. The applicability of functionalized MSNs as platforms for benznidazole delivery into T. cruzi parasites was assessed. The results demonstrate that the proposed system is a potential promising nanoplatform for drug and gene delivery targeting neglected diseases such as Chagas disease.
G. A. Ferrari, et al., “Apparent Softening of Wet Graphene Membranes on a Microfluidic Platform,” ACS Nano, vol. 12, no. 5, pp. 4312-4320, 2018. Publisher's Version
A. P. M. Barboza, et al., “Compression-Induced Modification of Boron Nitride Layers: A Conductive Two-Dimensional BN Compound,” ACS Nano, pp. null, 2018. Publisher's Version
H. Chacham, A. P. M. Barboza, A. B. de Oliveira, C. K. de Oliveira, R. J. C. Batista, and B. R. A. Neves, “Universal deformation pathways and flexural hardening of nanoscale 2D-material standing folds,” Nanotechnology, vol. 29, no. 9, pp. 095704, 2018. Publisher's VersionAbstract
In the present work, we use atomic force microscopy nanomanipulation of 2D-material standing folds to investigate their mechanical deformation. Using graphene, h-BN and talc nanoscale wrinkles as testbeds, universal force–strain pathways are clearly uncovered and well-accounted for by an analytical model. Such universality further enables the investigation of each fold bending stiffness κ as a function of its characteristic height h 0 . We observe a more than tenfold increase of κ as h 0 increases in the 10–100 nm range, with power-law behaviors of κ versus h 0 with exponents larger than unity for the three materials. This implies anomalous scaling of the mechanical responses of nano-objects made from these materials.
R. F. Dias, J. da Rocha Martins, H. Chacham, A. B. de Oliveira, T. M. Manhabosco, and R. J. C. Batista, “Nanoporous Graphene and H-BN from BCN Precursors: First-Principles Calculations,” The Journal of Physical Chemistry C, vol. 122, no. 7, pp. 3856-3864, 2018. Publisher's Version
2017
E. E. de Moraes, M. D. Coutinho-Filho, and R. J. C. Batista, “Transport Properties of Hydrogenated Cubic Boron Nitride Nanofilms with Gold Electrodes from Density Functional Theory,” ACS Omega, vol. 2, no. 4, pp. 1696-1701, 2017. Publisher's Version
J. A. Gonçalves, R. Nascimento, M. J. S. Matos, A. B. de Oliveira, H. Chacham, and R. J. C. Batista, “Edge-Reconstructed, Few-Layered Graphene Nanoribbons: Stability and Electronic Properties,” The Journal of Physical Chemistry C, vol. 121, no. 10, pp. 5836-5840, 2017. Publisher's VersionAbstract

J. Phys. Chem. C, 2017, 121 (10), pp 5836–5840

We report a first-principles study of edge-reconstructed, few-layered graphene nanoribbons. We find that the nanoribbon stability increases linearly with increasing width and decreases linearly with increasing number of layers (from three to six layers). Specifically, we find that a three-layer 1.3 nm wide ribbon is energetically more stable than the C60 fullerene, and that a 1.8 nm wide ribbon is more stable than a (10,0) carbon nanotube. The morphologies of the reconstructed edges are characterized by the presence of five-, six-, and sevenfold rings, with sp3 and sp2bonds at the reconstructed edges. The electronic structure of the few-layered nanoribbons with reconstructed edges can be metallic or semiconducting, with band gaps oscillating between 0 and 0.28 eV as a function of ribbon width.

2016
V. F. L. Filho, et al., “Effect of TiO2 Nanoparticles on Polyaniline Films Electropolymerized at Different pH,” The Journal of Physical Chemistry C, vol. 120, no. 27, pp. 14977-14983, 2016. Publisher's Version
C. K. B. de Vasconcelos, R. J. C. Batista, M. G. R. da Régis, T. M. Manhabosco, and A. B. de Oliveira, “A simple model for solute–solvent separation through nanopores based on core-softened potentials,” Physica A: Statistical Mechanics and its Applications, vol. 453, pp. 184 - 193, 2016. Publisher's VersionAbstract
Abstract We propose an effective model for solute separation from fluids through reverse osmosis based on core-softened potentials. Such potentials have been used to investigate anomalous fluids in several situations under a great variety of approaches. Due to their simplicity, computational simulations become faster and mathematical treatments are possible. Our model aims to mimic water desalination through nano-membranes through reverse osmosis, for which we have found reasonable qualitative results when confronted against all-atoms simulations found in the literature. The purpose of this work is not to replace any fully atomistic simulation at this stage, but instead to pave the first steps towards coarse-grained models for water desalination processes. This may help to approach problems in larger scales, in size and time, and perhaps make analytical theories more viable.
A. B. Oliveira, H. Chacham, J. S. Soares, T. M. Manhabosco, H. F. V. de Resende, and R. J. C. Batista, “Vibrational G peak splitting in laterally functionalized single wall carbon nanotubes: Theory and molecular dynamics simulations,” Carbon, vol. 96, pp. 616-621, 2016. Publisher's Version
2015
C. K. Oliveira, et al., “Crystal-oriented wrinkles with origami-type junctions in few-layer hexagonal boron nitride,” Nano Research, vol. 8, no. 5, pp. 1680-1688, 2015. Publisher's Version
S. M. Manhabosco, R. J. C. Batista, S. Neves da Silva, and L. F. P. Dick, “DETERMINATION OF CURRENT MAPS BY SVET OF HOT-DIP GALVANIZED STEEL UNDER SIMULTANEOUS STRAINING,” Electrochimica Acta, vol. 168, pp. 89-96, 2015. Publisher's Version
A. L. de Lima, L. A. M. Muessnich, T. M. Manhabosco, H. Chacham, R. J. C. Batista, and A. B. Oliveira, “Soliton instability and fold formation in laterally compressed graphene,” Nanotechnology, vol. 26, no. 4, 2015. Publisher's Version
2014
A. M. Marques dos Santos, et al., “Corrosion and cell viability studies of graphite-like hydrogenated amorphous carbon films deposited on bare and nitrided titanium alloy,” Corrosion Science, vol. 82, pp. 297-303, 2014. Publisher's Version
R. J. C. Batista, S. S. Carara, T. M. Manhabosco, and H. Chacham, “A Ferromagnetic Pure Carbon Structure Composed of Graphene and Nanotubes: First-Principles Calculations,” Journal of Physical Chemistry C, vol. 118, no. 15, pp. 8143-8147, 2014. Publisher's Version

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