Initial Solvent-Driven Nonequilibrium Effect on the Adsorption Layer of Polymer Nanocomposites*

There have been extensive efforts to characterize interfacial layers in polymer nanocomposites (PNCs), which determines the final structures and properties of PNCs. While tremendous studies have focused on intrinsic parameters of components such as size, shape, chemistry, an understanding for the variation of the structure and dynamics under different processing conditions is relatively lacking. In this work, we report that the initial dispersing solvent, which is not present in final PNCs, induces nonequilibrium effects on polymer chain dynamics at interfaces. By employing ¹H NMR free induction decay, we probe that the quantity rather than the mobility of interfacial polymers can be changed depending on the initial solvent, which leads to a difference in thickness of interfacial layers. Accordingly, the particle microstructures and rheological properties are greatly influenced observed by small-angle X-ray scattering and oscillatory rheometry experiments. In addition, we reveal that the outcome of the nonequilibrium effect driven by the initial solvent becomes more prominent at effective range of particle volume fraction related to the polymer chain dimension.