Abstract
Polymer nanocomposites (PNCs) are important materials that are widely used in
many current technologies and potentially have broader applications in the future due
to their excellent property of tunability, light weight and low cost. However,
expanding the limits in property enhancement remains a fundamental scientific
challenge. Here, we demonstrate that well-dispersed, small (diameter ~1.8 nm)
nanoparticles with attractive interactions lead to unexpectedly large and qualitatively
new changes in PNC structural dynamics in comparison to conventional composites
based on particles of diameter ~10-50 nm. At the same time, the zero-shear viscosity
at high temperatures remains comparable to that of the neat polymer, thereby retaining
good processibility and resolving a major challenge in PNC applications. Our results
suggest that the nanoparticle mobility and relatively short lifetimes of nanoparticlepolymer
associations open qualitatively new horizons in tunability of macroscopic
properties in nanocomposites with high potential for the development of new
functional materials.
