A Facile Strategy to Fabricate Tough and Adhesive Elastomers by In Situ Formation of Coordination Complexes as Physical Crosslinks

Coordination bonds with a dynamic nature and wide-spectrum bond energy have gained great popularity in use for fabricating tough soft materials. However, most existing coordination-based elastomers are prepared through complicated procedures, usually involving elaborate synthesis of ligand-containing monomers or polymers, ion diffusion to form coordination complexes, and removal of organic solvent during the synthesis, which are neither easy operation nor environmentally friendly. Here, a facile and effective strategy is demonstrated to fabricate tough metallosupramolecular elastomers by one-pot polymerization of aqueous precursor solutions containing commercial agents, 2-acrylamido-2-methyl-1-propanesulfonic acid, 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate, and Zr4+ ions. After solvent (i.e. water) evaporation, the obtained elastomers are transparent and extremely tough owing to the presence of sulfonate-Zr4+ coordination complexes as physical crosslinks. Their mechanical properties are tunable over a wide spectrum by adjusting the composition of copolymers and the density of coordination bonds. This eco-friendly strategy is further extended to various commercial monomers, manifesting good universality to toughen elastomers. Furthermore, the abundant functional groups of copolymers make the elastomers adhesive to various substrates including themselves, favoring applications such as interfacial adhesion and encapsulations. The easy fabrication, tunable mechanical properties, and adhesion ability endow the elastomers with great potential as the substrate of wearable soft electronics.