(289b) Mussel-Inspired, Tough Elastomer with Dynamic Bonding

Tough elastomers are of great importance in the automobile and aerospace industry, as well as in several biomedical applications. Current bioinspired tough elastomers have limited applications because their mechanical properties are compromised due to moisture sensitivity. We prepared an epoxy-based monomer containing dynamic bonds, catechol-iron coordination, inspired by marine mussel’s toughening strategy. Tough elastomer composites were then synthesized by loosely crosslinking this monomer along with a covalently crosslinked hydrophobic epoxy monomer backbone. Raman spectroscopy showed the presence of catechol-iron tris coordinate crosslinks in the elastomers in the region of 512 - 590 cm^-1. FTIR spectroscopy demonstrated the absence of primary amine groups, confirming that the crosslinker was completely consumed during the reaction. Tensile tests revealed that the ultimate tensile strength extensibility and toughness of the elastomer composite were several magnitudes higher when compared to the relevant controls in a dry and moisture-laden conditions. Cyclic-loading and unloading tests suggested that the elastomer composites were able to recover from up to 50 % of the applied strain retain their original mechanical strength. This was attributed to the dynamic coordinate crosslinking between catechol and iron ions, which endowed the polymers with elevated mechanical properties and the ability to retain its structural integrity despite the application of external strain.