The Swelling of Clays: Molecular Simulations of the Hydration of Montmorillonite

Karaborni, S.; Smit, Berend; Heidug, Wolfgang; Urai, János L.; Oort, Eric van

doi:10.1126/science.271.5252.1102

Cited by 399 publications

(300 citation statements)

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“…10 We surmise that the cross terms are negligible, also cubic and quartic contributions to bonds and angles could be avoided. Moreover, modeling of the dispersive interactions with an 4 r distance dependence might improve the performance. 12 In spite of these possible improvements, our augmented cff91 fares well and both the hydrocarbon part and the mineral part are reproduced within few percent of geometric deviations.…”

Section: Details Of the Simulationmentioning

confidence: 99%

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Analysis of the phase transitions in alkyl-mica by density and pressure profiles

Heinz

Paul

Suter

et al. 2004

The Journal of Chemical Physics

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In a previous work [H. Heinz, H. J. Castelijns, U. W. Suter, J. Am. Chem. Soc. 115, 9500 (2003)], we developed an accurate force field and simulated the phase transitions in C 18 -mica (octadecyltrimethylammonium-mica) as well as the absence of such transitions in 2C 18 -mica (dioctadecyldimethylammonium-mica) between room temperature and 100 °C. Here we analyze (i) average z-coordinates of the carbon atoms and interdigitation of the hydrocarbon bilayers, (ii) density profiles and (iii) pressure profiles of the structures along all Cartesian axes. In C 18 -mica, the standard deviation in the z coordinate for the chain atoms is high and more than doubles in the disordered phase. The order-disorder transition is accompanied by a change in the orientation of the ammonium headgroup, as well as decreasing tensile and shear stress in the disordered phase. In 2C 18 -mica, the standard deviation in the z coordinate for the chain atoms is low and does not increase remarkably on heating. The backbones display a highly regular structure, which is slightly obscured by rotations in the C 18 backbones and minor headgroup displacements at 100 °C. Close contacts between the bulky headgroups with sidearms cause significant local pressure which is in part not relieved at 100 °C. An increase of the basal-plane spacing at higher temperature is found in both systems due to larger separation between the two hydrocarbon layers and an increased z spacing between adjacent chain atoms (= decreased tilt of the chains relative to the surface normal), and, in C 18 -mica only, a stronger upward orientation of the C 18 chain at the ammonium headgroup. The likelihood for chain interdigitation between the two hydrocarbon layers is 24 % to 30 % for C 18 -mica, and 65 % to 26 % for 2C 18 -mica (for 20 °C to 100 °C).3 of 20 mica_analysis_revised5

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Section: Details Of the Simulationmentioning

confidence: 99%

“…[1][2][3][4][5] Mica sheets act as mechanically reinforcing additives, which also allow for different colors and optical effects (glittering) of the composite material. Surface modification with hydrocarbon tails is necessary to match the polarity to that of the polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the phase transitions in alkyl-mica by density and pressure profiles

Heinz

Paul

Suter

et al. 2004

The Journal of Chemical Physics

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“…GC simulations have been performed in the past by several authors at a fixed interlayer spacing. [19][20][21] For instance, Karaborni et al 20 used the minima in disjoining pressure as a function of the interlayer spacing calculated from a series of constant VT simulations to determine the stable states of Na-montmorillonite. They employed a combination of molecular dynamics and Monte Carlo techniques.…”

Section: Introductionmentioning

confidence: 99%

Adsorption isotherms of water in Li–, Na–, and K–montmorillonite by molecular simulation

Hensen

Tambach

Bliek

et al. 2001

The Journal of Chemical Physics

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133

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A biased Monte Carlo method for the insertion of water in dense clay-water systems is presented. The use of this algorithm results in a considerable increase of the success rate of insertion attempts. It allows us to compute water adsorption isotherms up to high water densities, where the conventional Monte Carlo scheme fails. The isotherms were calculated by a combination of molecular dynamics and grand-canonical Monte Carlo simulation for Li-, Na-, and Kmontmorillonite at a fixed d(001) spacing of 12.0 Å. At low water pressure, the degree of clay hydration is governed by the type of counterion, Li-montmorillonite having the highest water content. Hydrogen bonding between water molecules is absent. Li ϩ and Na ϩ are small enough to be organized in two layers close to the clay mineral surfaces, whereas K ϩ is mainly located in the midplane. In both cases, the water molecules primarily reside in the midplane of the interlayer. Increasing the water pressure leads to water adsorption at higher energy sites closer to the surface, i.e., coordinating to the structural OH groups in the hexagonal cavities. A hydrogen bond network is formed in the clay interlayer. This points to water condensation and leads to a sharp increase in the clay water content.

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“…DOI: 10.1103/PhysRevLett.104.016101 PACS numbers: 68.37.Ps, 07.79.Lh Muscovite mica ( Fig. 1) is known as a prototype of clay minerals and hence has importance in fundamental research regarding clay swelling in geological science [1][2][3] and cloud seeding in ecological science [4,5]. In addition, owing to the ease of cleavage to present an atomically flat surface, a mica-water interface has been widely used as a model system to investigate nanofluidics in engineering and physics [6], lubrication in tribology, and molecular adsorption and diffusion in biology and chemistry.…”

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Atomic-Scale Distribution of Water Molecules at the Mica-Water Interface Visualized by Three-Dimensional Scanning Force Microscopy

et al. 2010

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We have developed a method referred to as three-dimensional scanning force microscopy (3D-SFM) which enables us to visualize water distribution at a solid-liquid interface with an atomic-scale resolution in less than 1 min. The 3D-SFM image obtained at a mica-water interface visualizes 3D distributions of adsorbed water molecules above the center of hexagonal cavities and the laterally distributed hydration layer. The atomically resolved 3D-SFM image showing mirror symmetry suggests the existence of surface relaxation of the cleaved mica surface next to the aqueous environment. DOI: 10.1103/PhysRevLett.104.016101 PACS numbers: 68.37.Ps, 07.79.Lh Muscovite mica ( Fig. 1) is known as a prototype of clay minerals and hence has importance in fundamental research regarding clay swelling in geological science [1][2][3] and cloud seeding in ecological science [4,5]. In addition, owing to the ease of cleavage to present an atomically flat surface, a mica-water interface has been widely used as a model system to investigate nanofluidics in engineering and physics [6], lubrication in tribology, and molecular adsorption and diffusion in biology and chemistry. To date, the water distribution at a mica-water interface has been extensively studied by various techniques [7][8][9][10][11][12][13]. However, its atomistic model has not been established due to the difficulties in visualizing molecular-scale water distribution directly at a solid-liquid interface.Scanning force microscopy (SFM) is a nanoscale imaging technique which visualizes an ''isosurface'' of an interaction force acting between a sharp tip and a surface as a two-dimensional (2D) image [ Fig. 2(a)]. SFM has widely been used for imaging atomic-scale structures at solid-liquid, solid-air, and solid-vacuum interfaces. However, an interface inherently has a three-dimensional (3D) extent in subnanometer dimensions. Therefore, a 2D image obtained by SFM often fails to present important nature of interfacial phenomena. In particular, at a solidliquid interface, solvent molecules interacting with a surface often show 3D local distribution, which has not been fully accessible with conventional 2D-SFM. Here we propose a method referred to as 3D-SFM [ Fig. 2(b)], which enables us to visualize 3D distribution of water at a micawater interface in 53 sec with an atomic-scale resolution. With the obtained 3D-SFM image, we discuss the 3D distribution of adsorbed water molecules and hydration layers as well as the atomic-scale structure of cleaved mica surface next to an aqueous environment.Although the basic principles of 2D-and 3D-SFMs are applicable to various SFM operating modes, here we explain them in the case of frequency modulation (FM) detection mode [14], where the tip-sample interaction force is detected as a resonance frequency shift (Áf) of the vibrating cantilever. In 2D-SFM, the vertical tip position (z t ) is regulated to keep the Áf constant. With this tipsample distance regulation, a tip is laterally scanned in XY to present a 2D height image of ''Áf isosu...

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The Swelling of Clays: Molecular Simulations of the Hydration of Montmorillonite

Cited by 399 publications

References 25 publications

Analysis of the phase transitions in alkyl-mica by density and pressure profiles

Analysis of the phase transitions in alkyl-mica by density and pressure profiles

Adsorption isotherms of water in Li–, Na–, and K–montmorillonite by molecular simulation

Atomic-Scale Distribution of Water Molecules at the Mica-Water Interface Visualized by Three-Dimensional Scanning Force Microscopy

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