Modeling gas transport in polymer-grafted nanoparticle membranes.

We use coarse-grained molecular dynamics simulations to study gas diffusion within nanocomposites consisting of matrix-free polymer-grafted nanoparticles. We compare the transport of gas penetrants in systems using polymer models with and without an angle potential and show that gas diffusion enhancement occurs in nanocomposite systems only with the angle potential. This enhancement is related to the free volume in the system, but the cage size experienced by the gas penetrant seems to be a more relevant indicator of gas diffusion enhancement. The enhancement seen in our simulations is smaller than that observed in experiments.