(543f) Probing the Interface of Irreversible Adsorption in Polymer Nanocomposites

Annealing above the glass transition temperature (T_g) can prompt the formation of irreversibly adsorbed layers at polymer-substrate interfaces, which can subsequently influence the local and bulk properties of polymeric systems. This irreversible adsorption is predicted to be particularly influential in polymer nanocomposites due to their high processing temperatures and substantial interfacial area. However, until now the local and bulk effects of irreversible adsorption in polymer nanocomposites have not been directly described. Herein, we consider the effects of irreversible adsorption in polystyrene-silica nanocomposites using conventional bulk DSC measurements as well as direct, local techniques such as fluorescence spectroscopy to illuminate the relationship between local T_g perturbances proceeding from irreversible adsorption and overall nanocomposite properties. We also characterize the growth of the adsorbed layers as a function of annealing time. This characterization of local interfacial dynamics provides insights necessary for the engineering of polymer nanocomposite materials.