Glassy dynamics of an all-Polymer Nanocomposite based on Polystyrene single-chain Nanoparticles

We employ broadband dielectric spectroscopy (BDS) and fast scanning calorimetry (FSC) to provide insights on the glassy dynamics of an all-polymer nanocomposite made of linear poly(vinyl methyl ether) (PVME) with dispersed single-chain nanoparticles (SCNPs) based on polystyrene (PS). In doing so we obtain information on both the molecular mobility and the way equilibrium is recovered in the glassy state, the so-called physical aging. Our results show the presence of a PVME matrix with glassy dynamics identical to that of bulk PVME. However, the PVME/SCNPs mixture presents physical aging effects at considerably higher temperatures, as high as 80 K above the glass transition temperature (T) of PVME. The connection of these effects with a slow relaxational component detected by BDS, originating from SCNPs enriched by PVME, is highlighted. Accordingly, we conclude that the PVME/SCNPs mixture gives rise to a nanocomposite where the fillers behave similarly to PS-rich blends with PVME. Altogether our results highlight the hybrid nature, between that of a conventional nanocomposite and that of a miscible polymer blend, of the investigated system.We acknowledge financial support from the project PGC2018-094548-B-I00 (MICINN-Spain and FEDER-UE) and the project IT-1175-19 (Basque Government