Viscosity reduction in polymer nanocomposites: Insights from dynamic neutron and X-ray scattering

Abstract

The addition of nanoparticles to a polymer matrix can in certain cases induce a reduction in viscosity, with respect to the pure matrix, in the resulting composites. This counterintuitive phenomenon cannot be explained using the most common rheological models. For this reason, it has been chosen as a good example in this paper to demonstrate the value and methods of dynamic X-ray and neutron scattering techniques for the investigation of polymer nanocomposites. An overview of the main results on this topic is presented together with an introduction to the basic concepts relating to X-ray photon correlation spectroscopy, neutron backscattering, and neutron spin echo measurements.