Molecular Dynamics Simulations of Intercalated Poly(ε-Caprolactone)-Montmorillonite Clay Nanocomposites

Gardebien, Fabrice; Gaudel‐Siri, Anouk; Brédas, Jean‐Luc; Lazzaroni, Roberto

doi:10.1021/jp0493069

Cited by 48 publications

(64 citation statements)

References 57 publications

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“…It is wellknown, both from simulation [14][15][16][43][44][45][46][47] and from experimental studies, 32,34 that the presence of layered silicates in a polymer matrix causes modifications in the chain conformation next to the particle surface. In particular, considering the density of the organic species, there seems to be a tendency of the quats and polymer chains to adopt a layered conformation.…”

Section: Simulation Methods and Computational Detailsmentioning

confidence: 99%

“…In particular, considering the density of the organic species, there seems to be a tendency of the quats and polymer chains to adopt a layered conformation. 43,44 In order to investigate this behavior, we developed an original procedure to simulate quat and polymer chain intercalation into the clay galleries. For the simulations, we used the same molecular models employed in the NVT binding energy calculations described above.…”

Section: Simulation Methods and Computational Detailsmentioning

confidence: 99%

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Polymer−Clay Nanocomposites: A Multiscale Molecular Modeling Approach

et al. 2007

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A hierarchical procedure bridging the gap between atomistic and mesoscopic simulation for polymer-clay nanocomposite (PCN) design is presented. The dissipative particle dynamics (DPD) is adopted as the mesoscopic simulation technique, and the interaction parameters of the mesoscopic model are estimated by mapping the corresponding energy values obtained from atomistic molecular dynamics (MD) simulations. The predicted structure of the nylon 6 PCN system considered is in excellent agreement with previous experimental and atomistic simulation results. IntroductionBlending molten polymer and inorganic clays can result in a class of new materials, in which nanoscale clay particles, generally layered silicates, are molecularly dispersed within the polymeric matrix. Such polymer-clay nanocomposites (or PCNs) exhibit dramatic increases in several properties, including mechanical strength and heat resistance, and a decrease in gas permeability when compared to the polymeric matrix alone. [1][2][3][4][5][6][7] Importantly, the improvement in these properties is achieved at very low loadings of the inorganic component, typically 1-10 wt %, thus rendering PCNs lighter in weight than any other conventionally filled polymer. These unique features make PCNs ideal materials for applications such as high barriers for food or pharmaceutical packaging to strong, heat resistant automotive components, just to name a few. Fabricating these materials in an efficient and cost-effective manner, however, poses significant synthetic challenges. To appreciate these challenges, let us discuss briefly the structure of layered silicates by considering montmorillonite (MMT) as a prime example. This inorganic clay consists of stacked silicate sheets, each approximately 200 nm long and 1 nm thick. The spacing between each sheet (or gallery) is also of the order of 1 nm, and this quantity is clearly smaller than the average radius of gyration of any conventional polymer. Therefore, entropy generally constitutes a large barrier that prevents the polymer from penetrating these galleries and becoming an intercalated material. Accordingly, there is a number of critical issues that need to be addressed in order to optimize the design and production of PCNs. Of foremost importance is the isolation of the conditions that result in a promotion of the polymer penetration into the narrow clay galleries. If, however, the sheets ultimately phase-separate from the polymer matrix, the mixture will not exhibit the improved strength, heat resistance, or barrier properties mentioned above. Accordingly, it is also essential to determine the factors that control the macroscopic phase behavior of the mixture. Finally, the properties of the PCNs commonly depend on the structure of the material; thus, it is of particular interest to establish the morphology of the final composite.

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Section: Simulation Methods and Computational Detailsmentioning

confidence: 99%

Section: Simulation Methods and Computational Detailsmentioning

confidence: 99%

Polymer−Clay Nanocomposites: A Multiscale Molecular Modeling Approach

et al. 2007

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“…MD simulation is a numerical modeling technique for studying the molecular behavior of different substances (Allen and Tildesley, 1989;Rapaport, 1997;Fermeglia et al, 2003;Shevade et al, 2003;Fermeglia et al, 2004;Gardebien et al, 2004;Minisini and Tsobnang, 2005). The modeling process involves several key steps, namely, (1) construction of the atomistic geometry; (2) definition of atomic interaction; (3) governing equations for the system; (4) initialization and energy minimization; (5) conditions of simulation; (6) integration scheme and (7) calculation of concerned properties.…”

Section: Fundamentals Of MD Simulationmentioning

confidence: 99%

Structural solution using molecular dynamics: Fundamentals and a case study of epoxy-silica interface

Büyüköztürk

Buehler

Lau

et al. 2011

International Journal of Solids and Structures

153

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a b s t r a c tIn this paper, the molecular dynamics (MD) simulation technique is described in the context of structural mechanics applications, providing a fundamental understanding of the atomistic approach, and demonstrating its applicability. Atomistic models provide a bottom-up description of material properties and processes, and MD simulation is capable of solving the dynamic evolution of equilibrium and non-equilibrium processes. The applicability of the technique to structural engineering problems is demonstrated through an interface debonding problem in a multi-layered material system usually encountered in composite structures. Interface debonding may lead to a possible premature failure of fiber reinforced polymer (FRP) bonded reinforced concrete (RC) structural elements subjected to moisture. Existing knowledge on meso-scale fracture mechanics may not fully explain the weakening of the interface between concrete and epoxy, when the interface is under moisture; there is a need to study the moisture affected debonding of the interface using a more fundamental approach that incorporates chemistry in the description of materials. The results of the atomistic modeling presented in this paper show that the adhesive strength (in terms of energy) between epoxy and silica is weakened in the presence of water through its interaction with epoxy. This is correlated with the existing meso-scale experimental data. This example demonstrates that MD simulation can be effectively used in studying the durability of the system through an understanding of how materials interact with the environment at the molecular level. In view of the limitation of MD simulation on both length-and time-scales, future research may focus on the development of a bridging technique between MD and finite element modeling (FEM) to be able to correlate the results from the nano-to the macro-scale.

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“…Nevertheless, the MC simulation can use the force field scheme to describe the total energy of the system. These computational techniques are now used in various fields of research, such as carbon nanotubes channels [5][6][7], organic crystal packing, selfassembly monolayers (SAMs) [8][9][10][11], metal-organic frameworks (MOFs) [12][13][14][15], organoclay on inorganic crystalline [16][17][18][19], and colloidal nanoparticles aggregation [20,21]. The theoretical research on self-assembly mainly involves two factors, i.e., the driving interaction forces and spatial constraint.…”

Section: Self-assembly In Organic Materialsmentioning

confidence: 99%

Theoretical study on self-assembly in organic materials

Chen

Meng

et al. 2009

Front. Chem. China

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Theoretical work related to the self-assembly of organic materials was dealt with, and the various mechanisms leading to self-assembly, such as transition metal mediated self-assembly, constraint induced self-assembly, covalent bond based self-assembly and van der Waals interaction driven self-assembly, etc., were discussed. The formation of ordered structures could be attributed to the competition between short range attractive forces and long-range repulsion, which was arising from dipole interaction or may result from a different mechanism based on a purely repulsive isotropic short-range pair potential with two characteristic length scales. Such mechanism could be exploited in the study of self-assembly process. First principles SAPT(DFT) interaction energy calculations, combined with the WilliamsStone-Misquitta method, offer the ability to improve the molecular dynamics (MD) accuracy which could in turn be used in the prediction of crystal structures and selfassembly tendency. The combination of experimental and theoretical studies could open new breakthroughs over the design, synthesis, and characterization of selfassembled materials.

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Molecular Dynamics Simulations of Intercalated Poly(ε-Caprolactone)-Montmorillonite Clay Nanocomposites

Cited by 48 publications

References 57 publications

Polymer−Clay Nanocomposites: A Multiscale Molecular Modeling Approach

Polymer−Clay Nanocomposites: A Multiscale Molecular Modeling Approach

Structural solution using molecular dynamics: Fundamentals and a case study of epoxy-silica interface

Theoretical study on self-assembly in organic materials

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