Initial Solvent-Driven Nonequilibrium Effect on Structure, Properties, and Dynamics of Polymer Nanocomposites

Unusual structures and dynamic properties found in polymer nanocomposites (PNCs) are often attributed to immobilized (adsorbed) polymers at nanoparticle-polymer interfaces, which are responsible for reducing the intrinsic incompatibility between nanoparticles and polymers in PNCs. Although tremendous effort has been made to characterize the presence of immobilized polymers, a systematic understanding of the structure and dynamics under different processing conditions is still lacking. Here, we report that the initial dispersing solvent, which is not present after producing PNCs, drives these nonequilibrium effects on polymer chain dynamics at interfaces. Employing extensive small-angle scattering, proton NMR spectroscopy, and rheometry experiments, we found that the thickness of the immobilized layer can be dependent on the initial solvent, changing the structure and the properties of th…