Effect of cation exchange capacity on the structure and dynamics of poly(ethylene oxide) in Li+ montmorillonite nanocomposites

Authors

  • V. Kuppa,

    Corresponding author
    1. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
    • Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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  • E. Manias

    Corresponding author
    1. Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
    • Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
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Abstract

Molecular dynamics computer simulations are used to study the structure and dynamics of 1-nm wide films of poly(ethylene oxide) (PEO) confined between mica-type layered silicates of different cation exchange capacities (CEC). The simulation setup mimics experimental systems formed by intercalation of PEO in montmorillonite alumino-silicates with varied inherent charges. It is shown that the presence and population of lithium has a significant influence on the behavior of the system, in addition to the confinement-induced effects caused by the extreme spatial restriction. The structural features of the confined PEO are strongly altered with the number of Li+, which determines the polymer/inorganic interactions. The combination of the nanoconfinement and the presence of lithium preclude regular ordered arrangements of PEO, similar to those observed in the bulk unconfined polymer. The segmental dynamics of PEO in confinement are also greatly influenced by the presence of lithium, because of the strong interaction between Li+ and the oxygen of the PEO backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3460–3477, 2005

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