Influence of Polymer-Solid Contacts on Chain Order and Dynamics Probed by Advanced NMR Spectroscopy

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Advanced solid state NMR provides unique information about the conformation, chain order and dynamics of polymers in bulk, at the interface to solids and in the interphase in nanocomposites. Recent developments such as 1H-1H- or 1H-13C- double quantum NMR together with studies of 13C chemical shift anisotropy, 2H quadrupole coupling, or the Nuclear Overhauser Effect (NOE) offer ample opportunities to investigate extended chain conformations and their dynamics in systems with high selectivity, which are also studied in other projects of the Priority Programme. The spatial extension of the altered polymer behaviour will be probed by NMR spin diffusion. The focus will be on poly(butadiene) poly(n-alkylmethacrylates), poly(n-alkylacrylates), and poly(styrene), which have recently been shown to exhibit different tendencies to form extended chain conformations and nanostructures in bulk. In mixtures with sub-micron particles of inorganic oxides such as SiO2 or TiO2 we will study how the local structure and dynamics is influenced by the presence of the surface and how this changes the properties of the composites. In order to maximize the interface, the solids will be introduced as nanoparticles, with and without decoration by short chains of the polymers themselves. The NMR studies will performed in collaborations within the Priority Programme studying the same systems by X-ray scattering, optical spectroscopy, dielectric and mechanical relaxation and last, but not least computer simulation.