NMR investigations of self-healing processes in supramolecular elastomers

• Applicant: Professor Dr. Kay Saalwächter, Ph.D.
• Subject Area: Experimental and Theoretical Physics of Polymers ; Preparatory and Physical Chemistry of Polymers
• Term: from 2014 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259020601

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1568: Design and Generic Principles of Self-Healing Materials
• Participating Persons: Professor Dr. Wolfgang Binder; Dr. Frank Böhme; Professor Dr. Gert Heinrich; Professorin Dr. Annette M. Schmidt