Dispersion and Aggregation of Polymer Grafted Particles in Polymer Nanocomposites Driven by the Hardness and Size of the Grafted Layer Tuned by Attractive Graft–Matrix Interactions

Abstract

We use molecular dynamics (MD) simulations and Polymer Reference Interaction Site Model (PRISM) theory with a coarse-grained (CG) model to study polymer nanocomposites (PNCs) comprised of polymer grafted nanoparticles in a polymer matrix. Specifically, we describe the impact of increasing graft–matrix attraction on the PNC structure quantified in terms of the extent of interpenetration of matrix and graft chains (i.e., grafted layer wetting) and dispersion/aggregation of the grafted particles in the matrix via intermolecular pair correlation functions and structure factors. Past work on PNCs with attractive graft–matrix interactions had already established that grafted layer wetting–dewetting and dispersion-aggregation are two distinct phase transitions with the former being a continuous transition and the latter being a first-order transition with increasing graft–matrix attraction. In this paper, we go beyond that previous work and show that the dispersion and aggregation of polymer grafted particles in...