Dynamics and Structure of Metallo-supramolecular Polymers Based on Short Telechelic Precursors

We study the viscoelastic properties and the structure of a short hydrogenated polybutadiene (HPB) building block end-capped by terpyridine ligands. Adding metal ions in the sample leads to the formation of metallo-supramolecular junctions between the blocks, while the difference in polarity between the HPB chains and the metal complexes leads to the phase separation of the complexes into well-organized structures. By varying the nature and amount of metal ions added to the system, with the temperature, as well as with the sample thermal history, we show that it is possible to modulate these associations and obtain a very rich range of properties. In particular, while increasing the amount of metal ions leads to the sample reinforcement, it also causes a decrease of its melting temperature. This result is linked to the structure of the sample, which is characterized, in specific conditions, by the co-existence of two lamellar structures that we attribute to the existence of mono-complexes. The stability of these two lamellar structures is discussed based on the structural evolution during several heating and cooling ramps. We also show that the usually observed lamellar structure can be changed into a hexagonal structure if excess of metal ions are added to the sample.