Fast relaxation of coarse-grained models of polymer interphases by hybrid particle-field molecular dynamics: Polystyrene-silica nanocomposites as an example

Polymer composites attract large attention for their industrial use because of their unique features. The preparation of equilibrated melts of long entangled chains in the presence of a solid nanoparticle in molecular dynamics simulations is a very difficult task due to the slow relaxation time. We present a coarse-grained (CG) model suitable for polymer nanocomposites which combines Iterative-Boltzmann-Inversion derived polymer models, the hybrid particle-field representation of non-bonded interactions, and a convenient description of a solid nanoparticle suitable for hybrid particle-field models. The proposed approach is applied to test simulations of well characterized polystyrene-silica nanocomposites models. Finally, procedures for an efficient relaxation of pure polymer melts and interphase structures of large molecular weight nanocomposites are proposed.