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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Polymer and Molecular Dynamics, Friction and Rheology
CPP 40.7: Vortrag
Dienstag, 17. März 2020, 12:30–12:45, ZEU 255
Impact of hydrogen bonding strength on the structure and dynamics of supramolecular PEO — •Ana Brás1, Ana Arizaga1, Uxue Agirre1, Marie Dorau1, Patricia Bach1, Judith E. Houston2,3, Aurel Radulescu3, Margarita Kruteva4, and Annette M. Schmidt1 — 1UzK, Cologne, Germany — 2ESS, Lund, Sweden — 3FZJ, Garching, Germany — 4FZJ, Jülich, Germany
In this work we investigate supramolecular poly(ethylene oxide) (PEO) oligomers at the entanglement molar mass (Me) with different hydrogen bonding end groups, such as diaminotriazine (Dat) and thymine-1- acetic acid (Thy), as well as 2-ureido-4[1H]-pyrimidinone (Upy). Small angle scattering and rheology were combined to study the influence of different end-groups association strength as Upy is highly self-associative in comparison to the heterocomplementary pair Thy/Dat. Results on the structure provide insight into the underlying molecular mechanisms and reveal that while Upy-terminated chains phase segregate, forming network-like systems, the Thy/Dat pair-terminated system self-assemble to linear chains, thereby increasing the effective chain length. Moreover, rheological measurements also reveal differences in the viscoelastic response as Upy-terminated chains exhibit an extended rubbery plateau, typical of networks, and the pair Thy/Dat presents a Newtonian fluid behaviour. Remarkably, albeit both systems show end-group association, different hydrogen bonding species influence the type of associates. Acknowledgements: DFG for a research grant (BR5303) and Prof. Dr. D. Richter, Prof. Dr. R. Strey and Dr. Wim Pyckhout-Hintzen for fruitful discussions.