A Coarse-Grained Model for the Mechanical Behavior of Na-Montmorillonite Clay

Abstract

Sodium montmorillonite (Na-MMT) is one of the most commonly found swelling clay minerals with diverse engineering and technological applications. The nanomechanical properties of this mineral have been extensively investigated computationally utilizing molecular dynamics (MD) simulations to portray the molecular-level changes at different environmental conditions. As the environmentally found Na-MMT clays are generally sized within hundreds of nanometers, all-atomistic (AA) MD simulations of clays within such size range are particularly challenging due to computational inefficiency. Informed from atomistic modeling, a coarse-grained (CG) modeling technique can be employed to overcome the spatiotemporal limitation. The current study presents a modeling strategy to develop a computationally efficient model of Na-MMT clay with a typical size over ≃100 nm by shrinking the atomistic platelet thickness and reducing the number of center-layer atoms. Using the "strain-energy conservation" approach, the force field parameters for the CG model are obtained and the developed CG model can well preserve in-plane tension, shear, and bending behaviors of atomistic counterparts. Remarkably, the CG tactoid model of Na-MMT, a hierarchical multilayer structure, can reproduce the interlayer shear and adhesion as well as d-spacing among the clay sheets as of atomistic one to a good approximation while gaining significantly improved computational speed. Our study demonstrates the efficacy of the CG modeling framework, paving the way for the bottom-up multiscale prediction of mechanical behaviors of clay and related minerals.

Exploring the biointerfaces: ab initio investigation of nano-montmorillonite clay, and its interaction with unnatural amino acids

“…33 It consists of H, O, Si, Al, Mg, and Fe atoms arranged in two tetrahedral sheets and one octahedral sheet, with space between the triple-sheet layers. 21,34 A model for the mechanical behavior of Na-Montmorillonite clay 22 along with some first-principle studies conducted previously, provide valuable insight when examining the optical, structural, and electronic properties of transition metal-doped MMT 23,24 and Kaolinite 25 clay surfaces. Understanding the atomic-scale behavior of the montmorillonite clay surface is crucial due to its chemical properties, which enable the intercalation of organic molecules such as amino acids.…”

“…[18][19][20] Therefore, the use of polymer-based nanocomposites, including PCNs, represents a promising avenue for developing new materials with improved properties for tissue engineering applications. [21][22][23][24][25][26][27][28][29][30][31][32] In our study, we utilized a nanocomposite system to mimic the bone tissue environment, which consists of nano MMT clay co-doped with Fe and Mg. This clay, with the chemical formula NaSi 16 (Al 6 FeMg)O 20 (OH) 4 , exhibits negative charge states resulting from the isomorphic substitution of Al by Mg and Fe in MMT.…”

“…18–20 Therefore, the use of polymer-based nanocomposites, including PCNs, represents a promising avenue for developing new materials with improved properties for tissue engineering applications. 21–32…”

Molecular insights into the temperature and pressure dependence of mechanical behavior and dynamics of Na-montmorillonite clay

“…In particular, molecular dynamics (MD) simulations [33][34][35] have been extensively utilized to study the different physical properties of clay minerals, including MMT. [36][37][38] For instance, utilizing the Grand Canonical Monte Carlo (GCMC) method, in conjunction with MD, it was found that temperature moderately lessens the range of swelling pressure of clay with a d-spacing smaller than 16 Å. 39 In another work, using steered molecular dynamics (SMD), 40 Faisal and coworkers 37 have measured interaction energies between clays and cations during loading, enabling the evaluation of the mechanical behavior of Na-MMT tactoid under compression, tension, and shear at normal temperature and pressure.…”

First-Principles Study on Optoelectronic Properties of Fe-Doped Montmorillonite Clay

“…The atomistic model in this work is derived from MMT with a formula of Al 8 Si 16 O 40 (OH) 8 . , One of the Al atoms in the octahedral sheet is substituted with a Fe atom. The resulting Fe-MMT structures are geometry optimized under LS, IS, and HS, respectively.…”