Molecular Dynamics Characterization of Polymer Confinement in Nanocomposite Catalytic Membranes

Molecular modeling is used to characterize the first stage of the synthesis of nano-composite polymeric catalytic membranes, where a polymer is confined inside a layered material such as clay. Specifically, we focus on understanding the effect of confinement on the structure and dynamics of the polymer, and the diffusion and interactions of the K ⁺ cations present in the inorganic matrix with the polymer atoms. Classical molecular dynamics simulations are employed to study the structure and dynamics of poly-ethylene oxide (PEO) polymers inside of mica sheets with a gallery separation of 12.8 Å, at various polymer densities. Selected ab initio calculations performed in a single PEO chain yield atomic charge distribution and vibrational spectrum; the latter is compared with vibrational spectra obtained from the time evolution of the confined system.