The Critical Role of the Interfacial Layer in Polymer Nanocomposites
Invited
Abstract
In this talk we overview recent studies on structure and dynamics of the interfacial layer in various polymer nanocomposites (PNCs). First we emphasize the difference between the interfacial and rthe bound layer, which are often confused in literature. Then, we employ broad array of experimental techniques and MD-simulations that provide detailed characterization of the interfacial layer. These studies revealed a gradient in the interfacial layer dynamics, but no “glassy” or “dead“ layer. The thickness of the interfacial layer increases upon cooling to Tg, and depends strongly on polymer rigidity, increasing from ~2nm in flexible polymers to ~5 nm in more rigid ones. We discuss a possible connection of the interfacial layer thickness to the dynamic heterogeneity length scale. We emphasize usually overlooked dynamic property of the interfacial layer – strong suppression of the amplitude of structural relaxation on time scale of segmental dynamics. At the end, we present a general picture how microscopic parameters control the interfacial layer, and how by tuning the interfacial layer we can tune macroscopic properties of polymer nanocomposites.
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Presenters
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Alexei Sokolov
Oak Ridge National Lab, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA, Oak Ridge National Laboratory, University of Tennessee, Department of Chemistry, University of Tennessee, Knoxville, USA, Department of Chemistry, university of Tennessee
Authors
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Alexei Sokolov
Oak Ridge National Lab, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA, Oak Ridge National Laboratory, University of Tennessee, Department of Chemistry, University of Tennessee, Knoxville, USA, Department of Chemistry, university of Tennessee