Understanding and tailoring the viscoelastic response of polymer melts or concentrated solutions from the knowledge of their molecular structure (architecture) represents a formidable challenge and remains an important field of soft matter research. In order to further study the dynamics of these samples, we have developed a general coarse-grained approach based on the tube model, that we are now using as a tool to investigate the viscoelastic properties of complex, entangled polymer architectures.
In the present work, we extend this approach to investigate the dynamics of reversible polymer networks created through the metal-ligand association of entangled building blocks bearing terpyridine ligands. By varying their topology, their lengths, their chemistries, and the stickers density, a large variety of rheological properties can be obtained. In particular, while the nature of the metal ions used to create the metal-ligand associations largely influences the lifetime of a supramolecular interactions, we show that the dynamics of the reversible networks can also be largely modulated by playing with the possible cooperative effect of the stickers, with the ratio between entanglements and stickers density, as well as with the ratio between their association and disentanglement times [1]. As these physical networks usually present structural changes in the long term, we then explore the properties of double dynamics networks, in order to improve their resistance to creep and their shape recovery properties [2,3]. Understanding the relationship between composition and properties of these samples is an important step towards the design of polymer samples behaving as elastomers at room temperature, but re-processable at high temperature.
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Université catholique de Louvain (UCL), Belgium