The quantification of polyelectrolyte charge density effect on the chain segment dynamics of polymer nanocomposites of ultra-small nanoparticles

The complexation with ultra-small nanoparticles brings in great opportunity in polymer nanocomposite research due to the significantly varied chain dynamics from their extremely high specific surface area; however, the system complexity hinders the quantitative understanding of their structure-property relationship. Herein, polymers with varied quenched charge distribution are ionically complexed with 2 nm anionic metal oxide clusters ([NaP5W30O110]14-), while broadband dielectric spectroscopy is applied to probe the chain segment dynamics to quantify the effect of charge interaction. As suggested by x-ray scattering analysis, the homogeneous and molecular scale distribution of the particles can be achieved with the integrity of the molecular structures. With increased charge densities, no obvious glass transition process can be observed, while the temperature dependence of the chain segment dynamics transitions from Vogel-Fulcher-Tammann to Arrhenius type due to the enhanced confinement from increased ionic attraction strength. The time-charge density superposition of the system is proposed and verified for the unified understanding of chain relaxation dynamics of ionic nanocomposites.