WHEN: May 20, 2014, from 9:30 am
WHERE: Meeting room, 4th floor, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, Brno
Abstract:
Polymer nanocomposites are hybrid mixtures of hard nanoparticles and soft macromolecules that display novel and diverse microstructures, properties, and dynamical phenomena even in the molten state. We have developed a microscopic theory for the equilibrium structure and phase behavior of such systems that provides guidelines for realizing three qualitatively different spatial organizations of nanoparticles. Quantitative comparisons to x-ray and neutron scattering experiments on silica-based materials will be presented. We have also developed a dynamical theory for nanoparticle transport in unentangled and entangled polymer liquids that accounts for multiple non-hydrodynamic effects and failure of the Stokes-Einstein relation. Its predictions for diffusivity under dilute filler loading conditions are in very good agreement with recent computer simulations and experiments. At higher nanoparticle concentrations, polymer dynamics is modified in a length-scale-dependent manner. I will discuss a first principles theory of such effects for rigid rod and flexible chain polymer nanocomposites, focusing on how the modification of topological entanglements impacts the tube diameter and macromolecule anisotropic diffusivity.
The event has been supported by the EU Seventh Framework Programme under the "Capacities" specific programme (Contract No. 286154 - SYLICA)
