NMR investigations of self-healing processes in supramolecular elastomers

本项目旨在建立超分子弹性体微观链动力学与宏观力学和自愈性能之间的关系。研究的主题是离子弹性体以及基于与缔合基团功能化的聚合物的超分子热塑性弹性体，所有这些都是可用的，正在SPP 1568优先计划中进行研究。作为主要技术，我们结合了质子低场核磁共振技术的应用，得到了反映超分子相互作用寿命的链动力学信息，高场核磁共振技术，得到了超分子部分的动力学信息，以及动态流变学，得到了宏观弛豫时间尺度的信息。一个特别的焦点将是机械和核磁共振实验的非线性行为在高应变样品的比较，这反映了自愈动力学。核心科学问题是阐明链重组的分子时间尺度与宏观愈合或流动行为之间的定量关系，比较有和没有额外化学交联的样品。我们还讨论了实际相关端基的相对数量的估计和超分子交联结构的功能。

This project aims at establishing a correlation between the microscopic chain dynamics and the macroscopic mechanical and self-healing properties in supramolecular elastomers. The subjects of study are ionomeric elastomers as well as supramolecular thermoplastic elastomers based on polymers functionalized with associating groups, all of which are available and being studied within the priority programme SPP 1568. As main techniques, we combine the application of proton low-field NMR techniques, yielding information on the chain dynamics reflecting he lifetime of the supramolecular interactions, high-field NMR techniques, yielding information on the dynamics in the supramolecular moieties, and dynamic rheology, yielding information on the macroscopic relaxation timescales. A particular focus will be the comparison of mechanical and NMR experi¬ments of the non-linear behavior in highly strained samples, which reflects the self-healing dynamics. The central scientific question is the elucidation of the quantitative relationship between the molecular timescale of chain reorganization and the macroscopic healing or flow behavior, comparing samples with and without additional chemical crosslinks. We also address the estima¬tion of the relative amount of the actually associated endgroups and the functionality of the supramolecular crosslink structures.