Dresden 2017 – wissenschaftliches Programm
CPP 29.3: Vortrag
Dienstag, 21. März 2017, 14:30–14:45, ZEU 250
What controls the structure, and the linear and non-linear rheological properties of dense, dynamic supramolecular polymer networks? — •Klaus Schröter1, Tingzi Yan1, Florian Herbst2, Wolfgang H. Binder2, and Thomas Thurn-Albrecht1 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg — 2Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg
Telechelic polyisobutylenes with different functional groups and a series of molecular weights were investigated by means of small angle x-ray scattering and rheology. All samples form a dense, dynamic network of interconnected micelles resulting from aggregation of the functional groups and leading to viscoelastic behavior. The dynamic character of this network manifests itself in the appearance of terminal flow at long timescales. While the elastic properties are distinctly molecular weight dependent, the terminal relaxation time is controlled by the functional end groups. The yielding properties under large deformation during startup shear experiments can be understood by a model of stress activation of the dynamic bonds. Stress relaxation experiments help to separate the non-linear response into two contributions: a fast collapse of the network and a slow relaxation, happening on the time scale of the terminal relaxation. The latter is also shown to control self-healing of the collapsed structure.