PEO / SiO₂ nanocomposites: Correlating Polymer Morphology to Rheological Properties

Polymer nanocomposites, comprised of a polymer matrix and inorganic additives, possess improved and often innovative physicochemical properties compared to conventionally filled systems. In this work we report on the rheological behavior of a series of poly(ethylene oxide) / silica, PEO/SiO₂, nanocomposites through oscillatory shear rheology measurements. The nanohybrids were synthesized by dispersing spherical SiO₂ nanoparticles of two different radii within high molecular weight (Mw) PEO at different compositions in order to investigate the effect of the additive on the material rheological properties. PEO crystallinity was found to depend on the degree of spatial confinement that the nanoparticles impose as well as their adsorption capacity. Dynamic time and strain sweep tests verify the material thermal stability and linear viscoelastic behavior whereas dynamic frequency sweeps probe its dynamic response. The effect of nanoparticle size and concentration on the behavior is examined to correlate the morphological changes to the rheological response of the materials in an attempt to better understand the structure-properties relationship. Acknowledgements: This research has been co-financed by EU and Greek national funds (Action RESEARCH – CREATE - INNOVATE, MIS: 5030174).