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

先进的固态核磁共振提供了有关聚合物的构象、链序和动力学的独特信息，这些信息位于纳米复合材料的固体界面和界面处。最近的发展，如1H-1H-或1H-13C-双量子核磁共振，以及对13C化学位移各向异性、2H四极耦合或核Overhauser效应(NOE)的研究，为研究高选择性体系中的延伸链构象及其动力学提供了大量机会，这些也在优先方案的其他项目中进行研究。改变后的聚合物行为的空间扩展将通过核磁共振自旋扩散来探索。重点将集中在聚(丁二烯)聚(正构烷基甲基丙烯酸酯)、聚(正构烷基丙烯酸酯)和聚(苯乙烯)上，它们最近显示出在本体中形成扩链构象和纳米结构的不同趋势。在含有亚微米级无机氧化物的混合物中，如二氧化硅或二氧化钛，我们将研究表面的存在如何影响局部结构和动力学，以及这如何改变复合材料的性能。为了使界面最大化，固体将以纳米颗粒的形式引入，并由聚合物本身的短链修饰和不修饰。核磁共振研究将在优先方案的协作下进行，通过X射线散射、光学光谱、介电和机械松弛以及最后但并非最不重要的计算机模拟来研究相同的系统。

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.