Multiscale molecular simulations of grafted materials

Abstract

An overview of recent applications of hybrid particle-field Molecular Dynamics (hPF-MD) to grafted materials is presented. For such an aim, two classes of materials are considered: polymer nanocomposites and polymer brushes. In the first case, the hybrid approach demonstrates its efficiency to properly relax polymer chains even of high molecular weight. Also, results highlight the role played by configurational entropy of polymer chains in determining the effective (two-body and three-body) nanoparticle–nanoparticle interaction in the melt. A similar role emerges also in the investigation of polymer brushes, where hPF-MD simulations clarify the mechanisms underlying the “grafting to” process, pointing towards a partition by molecular weight of polymer chains. This effect, which causes the segregation of the chains with lower molecular weight in proximity of the substrate surface, is purely entropic and it is originated by the stretching of polymer chains during the grafting to reaction. This picture is also confirmed by a very recent combination of self-consistent field theory with the lattice-based reactive Monte Carlo method which allows to predict for the first time the final composition of the chains grafted on the surfaces.