Nanoscopic dispersions of inorganic nanoparticles have been shown to enhance polymer and polymer-blend performance. Critical to advancing nanocomposite technology are understanding the spatial distribution of the various constituents (inorganic, polymer, and additives), the influence of thermodynamic and kinetic factors, and control of nano- and mesoscale morphology. We have developed a coarse-grained molecular dynamics model to investigate the processes and interactions that determine the dispersion of a layered silicate (clay) in a polymer matrix by examining the initial steps of intercalation and exfoliation (1). One experimental approach to achieving intercalation and exfoliation is by infusing monomer into the galleries between the silicate sheets of the clay and performing the polymerization in situ. The phase behavior of organically modified layered silicates (OLS) in a non-reactive medium has been described by Onsager arguments (2). We have extended our coarse-grained model to investigate the phase behavior of OLS in binary mixtures of nonreactive solvents, specifically examining the dependence of component partitioning and intergallery diffusion rate on the composition of the exterior medium.
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