Dynamic Chalcogen Squares for Material and Topological Control over Macromolecules

Herein we introduce chalcogen squares via selenadiazole motifs as a new class of dynamic supramolecular bonding interactions for the modification and control of soft matter materials. We showcase selenadiazole motifs in supramolecular networks of varying primary chain length prepared through polymerization using tandem step-growth/Passerini multicomponent reactions (MCRs). Compared to controls lacking the selenadiazole motif, these networks display increased glass transition temperatures and moduli due to the chalcogen bonding linkages formed between chains. These elastomeric networks were shown to autonomously heal at room temperature, retaining up to 83 % of the ultimate tensile strength. Lastly, we use post-polymerization modification via the Biginelli MCR to add selenadiazole motifs to narrowly dispersed polymers for controlled topology in solution. Chalcogen squares via selenadiazoles introduce an exciting exchange mechanism to the realm of dynamic materials. We introduce and entirely new dynamic, non-covalent bonding interaction based on selenadiazole chalcogen squares which are capable of tuning bulk glass transition temperature, increase toughness, imbue self-healing abilities, and control hydrodynamic diameter of solvated macromolecular architectures. All of these properties can be accessed via a single selenadiazole containing molecule, easily and quickly incorporated into a broad array of polymer systems via Passerini and Biginelli multicomponent reactions. image