Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 29: Polymer Networks and Dynamics III: Mechanical Properties

CPP 29.3: Talk

Tuesday, March 21, 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.