Molecular dynamics study on the crack propagation in carbon doped polycrystalline boron-nitride nanosheets

Jam, Amir Namazian; Jam, Negin Namazian; Izadifar, Mohammadreza; Rabczuk, Timon

doi:10.1016/j.commatsci.2021.111066

Cited by 7 publications

(4 citation statements)

References 52 publications

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“…Computational approaches using molecular dynamics (MD) , and density functional theory (DFT) , have recently been employed to measure the mechanical properties of the most relevant hydrated phases of cementitious materials. Manzano et al computed the mechanical properties of crystalline calcium-silicate-hydrates, such as nekoite, foshagite, hillebrandite, jennite, and 9, 11, 14 Å tobermorite using molecular dynamics (MD) calculations.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Elastic Constants of Tobermorite Enhanced with Reduced Graphene Oxide through Hydroxyl vs Epoxy Functionalization: A First-Principles Study

Izadifar,

Dolado,

Thissen

et al. 2023

J. Phys. Chem. C

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Graphene-based materials are considered excellent candidates to implement cementitious nanocomposites due to their mechanical properties. This paper presents a comprehensive interface interaction that ends up with computing the elastic properties for four models of the C–S–H gel, taking tobermorite 14 Å as an example, with reduced graphene oxide (rGO) to form reinforced (tobermorite) cementitious nanocomposites within the density functional theory. We found that upon relaxing the model structures, the dissociation of hydroxyl functional groups from the hydroxyl/rGO lattice occurs not only in the presence of Ca2+ ions to compensate for local charges but even when the Ca2+ charges are compensated with hydroxyl groups. In contrast, rGO/CSH interactions remained close to the initial structural models of the epoxy rGO surface. The elastic constants showed high improvements for the cementitious nanocomposite of tobermorite 14 Å with intercalated hydroxyl/rGO layers. Thus, the bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio increased up to limits set as 165, 128, 134, and 15% compared to tobermorite 14 Å, respectively. In more detail, the specific values of the elastic constants were influenced by the interface, specifically the presence of hydroxyl or epoxy groups as well as how the charges of the Ca2+ ions were compensated. These findings are of interest for the design of future experiments that will help to engineer better rGO/cement composites.

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Section: Introductionmentioning

confidence: 99%

Theoretical Elastic Constants of Tobermorite Enhanced with Reduced Graphene Oxide through Hydroxyl vs Epoxy Functionalization: A First-Principles Study

Izadifar,

Dolado,

Thissen

et al. 2023

J. Phys. Chem. C

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“…Graphene is one of the best candidates, which is used in a wide variety of applications, such as nanocomposites, 18 nanoelectronics, 19 and nanoelectromechanical systems (NEMS), 20 just to name a few. 21,22 The graphenebased nanosheet without defects exhibits a tensile strength of 130 ± 10 GPa, 23 an elastic modulus of 1 ± 0.1 TPa, 24 and a thermal conductivity of 4100 ± 500 W(m K) −1 . 14,23,25−27 In the presence of oxygen containing groups on the graphenebased nanosheets, Dikin et al 28 reported that the tensile strength and elastic modulus of graphene oxide (GO) are equal to 30 (on average) and 130 GPa, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the outstanding mechanical, electrical, and thermal properties of graphene are the major reasons for fabrication of new nanocomposite materials with unique properties. Graphene is one of the best candidates, which is used in a wide variety of applications, such as nanocomposites, nanoelectronics, and nanoelectromechanical systems (NEMS), just to name a few. , The graphene-based nanosheet without defects exhibits a tensile strength of 130 ± 10 GPa, an elastic modulus of 1 ± 0.1 TPa, and a thermal conductivity of 4100 ± 500 W(m K) −1 . ,,− In the presence of oxygen containing groups on the graphene-based nanosheets, Dikin et al reported that the tensile strength and elastic modulus of graphene oxide (GO) are equal to 30 (on average) and 130 GPa, respectively. It has to be stressed that GO is a single graphene-based nanosheet, having its basal plane mostly populated with functional groups like hydroxyls and epoxies whereas the edge plane is mostly occupied by carbonyl and carboxyl groups.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies of Adsorption Reactions of Aluminosilicate Aqueous Species on Graphene-Based Nanomaterials: Implications for Geopolymer Binders

Izadifar,

Sekkal,

Dubyey

et al. 2023

ACS Appl. Nano Mater.

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Geopolymer nanocomposites incorporating carbon nanotube (CNT)/graphene-based nanomaterials have become an exciting area of research because of their exceptional interface compatibility, providing improved mechanical, electrical, and thermal properties for next-generation construction materials. Accordingly, geopolymers are superior candidates for the implementation of graphene-based nanocomposites. In this paper, a comprehensive examination through equilibrium density functional theory (DFT) with and without the contribution of van der Waals (vdW) dispersion interaction, along with ReaxFF molecular dynamics (ReaxFF-MD) computational modeling approaches, was carried out to comprehend the interaction mechanisms and adsorption energies between graphene-based nanosheets and primary aqueous species of geopolymer structure. Results showed that the interaction of Si(OH)4 aqueous species with the pristine graphene substrate has the weakest physical binding adsorption. The adsorption energy of silicate species on the pristine graphene substrate increased when involving interactions with sodium or potassium cations. Graphene-based nanomaterial surface functionalization with hydroxyl or carboxyl groups led to the higher adsorption energies of silicate and aluminate species due to the stronger electrostatic interaction. Computations also revealed that Na+, compared to K+, mostly increased the interfacial binding between the geopolymer and CNT/graphene-based nanomaterials. The computed MD results exhibited some qualitative agreement with ab initio calculations (at 0 K), with an overestimation tendency as expected due to the contribution of kinetic energy at 300 K. DFT results refute literature assumptions of a covalent oxo-bridging bond between silicon and carbon atoms, confirming electrostatic interactions (Coulomb interaction), with van der Waals (vdW) dispersion forces also playing a significant role in adsorption energy. Our study provides a systematic quantification of missing binding energy parameters and their implications for upscaling interface effects to the nanocomposite level.

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“…Then, the far-from-equilibrium kinetic Monte Carlo (KMC) approach was employed to investigate the upscaling atomistic dissolution rates of portlandite, representing the forward reaction rate. Moreover, to implement the KMC approach in a proper and accurate way, Salah Uddin et al in parallel study (Part 1) [1] provided input information about the reaction activation energy (∆G*) of the dissolution of calcium atoms (Ca) for different neighbor scenarios and for different facets (crystal planes or surface orientations) at room temperature by a molecular dynamic (MD) [23,24] computational method using ReaxFF coupled with a metadynamics approach as input values to compute the dissolution rates (r D ) according to transition state theory (Equation ( 1)). In fact, in the KMC upscaling approach, the dissolution and precipitation activation energies for a given site are sometimes written as the sum of the contribution of the n bonded neighbors [2].…”

Section: Introductionmentioning

confidence: 99%

Dissolution of Portlandite in Pure Water: Part 2 Atomistic Kinetic Monte Carlo (KMC) Approach

et al. 2022

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Portlandite, as a most soluble cement hydration reaction product, affects mechanical and durability properties of cementitious materials. In the present work, an atomistic kinetic Monte Carlo (KMC) upscaling approach is implemented in MATLAB code in order to investigate the dissolution time and morphology changes of a hexagonal platelet portlandite crystal. First, the atomistic rate constants of individual Ca dissolution events are computed by a transition state theory equation based on inputs of the computed activation energies (ΔG*) obtained through the metadynamics computational method (Part 1 of paper). Four different facets (100 or 1¯00, 010 or 01¯0, 1¯10 or 11¯0, and 001 or 001¯) are considered, resulting in a total of 16 different atomistic event scenarios. Results of the upscaled KMC simulations demonstrate that dissolution process initially takes place from edges, sides, and facets of 010 or 01¯0 of the crystal morphology. The steady-state dissolution rate for the most reactive facets (010 or 01¯0) was computed to be 1.0443 mol/(s cm2); however, 0.0032 mol/(s cm2) for 1¯10 or 11¯0, 2.672 × 10−7 mol/(s cm2) for 001 or 001¯, and 0.31 × 10−16 mol/(s cm2) for 100 or 1¯00 were represented in a decreasing order for less reactive facets. Obtained upscaled dissolution rates between each facet resulted in a huge (16 orders of magnitude) difference, reflecting the importance of crystallographic orientation of the exposed facets.

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Molecular dynamics study on the crack propagation in carbon doped polycrystalline boron-nitride nanosheets

Cited by 7 publications

References 52 publications

Theoretical Elastic Constants of Tobermorite Enhanced with Reduced Graphene Oxide through Hydroxyl vs Epoxy Functionalization: A First-Principles Study

Theoretical Elastic Constants of Tobermorite Enhanced with Reduced Graphene Oxide through Hydroxyl vs Epoxy Functionalization: A First-Principles Study

Theoretical Studies of Adsorption Reactions of Aluminosilicate Aqueous Species on Graphene-Based Nanomaterials: Implications for Geopolymer Binders

Dissolution of Portlandite in Pure Water: Part 2 Atomistic Kinetic Monte Carlo (KMC) Approach

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