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ICS-3 Vortrag: Dr. David GreenUniversity of Virginia, USA

"Connecting Diffusivity, Microstructure and Rheology of Polymer-Grafted Nanoparticles in Polymer Melts: Theory and Experiment"

26.Feb.2013 14:00
Seminarraum A1-A3, Building 04.6


The overarching objective of our work is to control the formulation of polymer blends and composites, which requires a detailed understanding of how the conformation of polymers at interfaces controls the dispersion of droplets or particles.  To this end, we discuss a novel way to reinforce polymer nanocomposites (PNCs) through the stretching of graft polymers, which occurs counterintuitively in lower molecular weight polymer melts. Using laser light scattering, mechanical rheology and self-consistent mean field calculations, we elucidate the essential mechanisms for uniform nanoparticle dispersion. Subsequently, we use ultra-small x-ray scattering, x-ray correlation spectroscopy, and statistical mechanics to show that stronger nanoparticle interactions occur in lower molecular weight melts due to brush stretching. To increase the impact of this work, we now seek strategic collaborations with interested researchers to further develop and implement optics and theory to quantify, predict, and control the linear viscoelasticity of the PNCs. Ultimately this collaboration will lead to the predictive control over the bottom-up, nanoscale design of PNCs through control over the wetting between polymers grafted to nanoparticles and the surrounding matrix.