Phase segregated supramolecular polymers based on isophthalic acid - pyridine H-bonding

New approaches to mechanically robust supramolecular polymers with special focus on reducing their complexity while targeting advanced functionalities.

Supramolecular polymers are molecular assemblies of monomer units which are connected through non-covalent interactions such as hydrogen bonding, metal-ligand complexation, π-π staking or ionic interactions. Thanks to the intrinsic reversibility of these secondary interactions, supramolecular polymers display a variety of interesting properties including enhanced processability, (self-)healing ability and shape-memory. On the other hand, this reversibility usually results in materials with limited mechanical properties. In order to overcome this drawback, dynamic bonds can be frozen by physically cross-linking polymer chains via phase segregation. For this purpose, soft telechelic polymers are tipically functionalized with supramolecular units as end-groups, which tend to associate and crystallize into hard phases that mechanically reinforce the soft matrix. The resulting materials combine low melt viscosity and stimuli responsiveness with good mechanical properties. We have recently found that isophthalic acid (IPA) terminated telechelic poly(ethylene-co-butylene) forms mechanically robust supramolecular networks upon addition of different commercial bipyridines. The simplicity of the IPA-Py motif and the high tunability of these materials by simple choice of one of the components make them very attractive from an application point of view. This project explores both the fundamental aspects of this system and its potential as the base of healable, thermoreversible two-component resins.

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