Journal ArticleDOI
Altered phase model for polymer clay nanocomposites.
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TLDR
It is concluded that, in order to accurately predict mechanical response of PCNs, it is necessary to take into account the molecular-level interactions between constituents of PCN, which are responsible for the enhanced nanomechanical properties ofPCNs.Abstract:
This paper describes a multiscale approach used to model polymer clay nanocomposites (PCNs) based on a new altered phase concept. Constant-force steered molecular dynamics (SMD) is used to evaluate nanomechanical properties of the constituents of intercalated clay units in PCNs, which were used in the finite element model. Atomic force microscopy and nanoindentation techniques provided additional input to the finite element method (FEM) model. FEM is used to construct a representative PCN model that simulates the composite response of intercalated clay units and the surrounding polymer matrix. From our simulations we conclude that, in order to accurately predict mechanical response of PCNs, it is necessary to take into account the molecular-level interactions between constituents of PCN, which are responsible for the enhanced nanomechanical properties of PCNs. This conclusion is supported by our previous finding that there is a change in crystallinity of polymeric phase due to the influence of intercalated clay units. The extent of altered polymeric phase is obtained from observations of a zone of the altered polymeric phase surrounding intercalated clay units in the "phase image" of PCN surface, obtained using an atomic force microscope (AFM). An accurate FEM model of PCN is constructed that incorporates the zone of the altered polymer. This model is used to estimate elastic modulus of the altered polymer. The estimated elastic modulus for the altered polymer is 4 to 5 times greater than that of pure polymer. This study indicates that it is necessary to take into account molecular interactions between constituents in nanocomposites due to the presence of altered phases, and furthermore provides us with a new direction for the modeling and design of nanocomposites.read more
Citations
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A review of recent research on nanoindentation of polymer composites and their constituents
TL;DR: A review of recent archival journal publications dealing with nanoindentation of polymer composites and their constituents, with emphasis on publications that have appeared since 2000, can be found in this article.
Journal ArticleDOI
Chemically Specific Multiscale Modeling of Clay–Polymer Nanocomposites Reveals Intercalation Dynamics, Tactoid Self‐Assembly and Emergent Materials Properties
TL;DR: A quantitative description is presented of the dynamical process of polymer intercalation into clay tactoids and the ensuing aggregation of polymer-entangled tactoids into larger structures, obtaining various characteristics of these nanocomposites, including clay-layer spacings, out-of-plane clay-sheet bending energies, X-ray diffractograms, and materials properties.
Journal ArticleDOI
Nanoclay Based Composite Scaffolds for Bone Tissue Engineering Applications
TL;DR: The ChiPgA composite scaffolds containing MMT clay modified with 5-aminovaleric acid are biocompatible and appears to satisfy some of the basic requirements of scaffolds for tissue engineering applications.
Journal ArticleDOI
Dynamic fluid states in organic-inorganic nanocomposite: Implications for shale gas recovery and CO2 sequestration
TL;DR: In this paper, a shale clay-kerogen nanocomposite with heterogeneous pore structure was built to investigate the dynamic characteristics of fluid states during pressure depletion and CO2 sequestration using molecular simulations for the first time.
Journal ArticleDOI
Carbon nanotube/reduced graphene oxide hybrid for simultaneously enhancing the thermal conductivity and mechanical properties of styrene -butadiene rubber
Shiqiang Song,Yong Zhang +1 more
TL;DR: In this paper, a novel hybrid of polymer functionalized-carbon nanotube and reduced graphene oxide (PCNT@RGO) was prepared by reversible addition-fragmentation chain transfer polymerization, esterification reaction and reduction process.
References
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VMD: Visual molecular dynamics
TL;DR: VMD is a molecular graphics program designed for the display and analysis of molecular assemblies, in particular biopolymers such as proteins and nucleic acids, which can simultaneously display any number of structures using a wide variety of rendering styles and coloring methods.
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CHARMM: A program for macromolecular energy, minimization, and dynamics calculations
Bernard R. Brooks,Robert E. Bruccoleri,Barry D. Olafson,David J. States,S. Swaminathan,Martin Karplus +5 more
TL;DR: The CHARMM (Chemistry at Harvard Macromolecular Mechanics) as discussed by the authors is a computer program that uses empirical energy functions to model macromolescular systems, and it can read or model build structures, energy minimize them by first- or second-derivative techniques, perform a normal mode or molecular dynamics simulation, and analyze the structural, equilibrium, and dynamic properties determined in these calculations.
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Polymer Layered Silicate Nanocomposites
TL;DR: In this paper, a new, versatile and environmentally benign synthesis approach by polymer melt intercalation is discussed. But, unlike in-situ polymerization and solution inter-calation, melt interalation involves mixing the layered silicates with the polymer and heating the mixture above the softening point of the polymer.
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NAMD2: Greater Scalability for Parallel Molecular Dynamics
Laxmikant V. Kale,Robert D. Skeel,Milind Bhandarkar,Robert Brunner,Attila Gursoy,Neal Krawetz,James C. Phillips,Aritomo Shinozaki,Krishnan Varadarajan,Klaus Schulten +9 more
TL;DR: The NAMD2 program is presented, which uses spatial decomposition combined with force decomposition to enhance scalability and modularly organized, and implemented using Charm++, a parallel C++ dialect, so as to enhance its modifiability.