Diminishing Effect of Bound Polymer Layers with Decreasing Nanoparticle Size

The attractive interactions between polymers and nanoparticles (NPs) in polymer composites can leads to the formation of a "bound" layer around the nanoparticle (NP) with very slow dynamics. We explore the degree to which bound polymer affects nanocomposite relaxation as NP size becomes progressively smaller. To explain the effects of NP size, we study the structural and dynamical (relaxation time, glass transition temperature) of polymer composites. First, we examine the dependence of relaxation on the distance from the nanoparticle interface. We then look at how the overall relaxation, which averages over the relaxation gradient, changes with NP size. Whether looking at local or overall relaxation, we show how the effects of NP on interfacial relaxation and bound polymer diminish as NP become smaller. In addition, we study the structural effects of NP size on the bound layer.