Tuning the mechanical properties of bioinspired catechol polymers by incorporating dual coordination bonds

Abstract

Coordination bonds between catechol-functionalized proteins and metal ions serve as sacrificial bonds that play essential roles in the expression of good mechanical performance and the self-healing properties of mussel byssal threads, which has inspired researchers to develop a range of catechol-based functional polymers. Herein, we investigated the mechanical properties of catechol-functionalized network polymers crosslinked by dual coordination bonds, namely catechol–Ca and catechol–B. As the bonding strengths are different, the viscoelastic properties of these materials can be controlled by changing the relative concentrations of these two bonds. The dual-coordination polymer with a 75:25 ratio of catechol–B:catechol–Ca (PB75Ca25) exhibited a higher Young’s modulus and break strength than the corresponding single-coordination polymer (PCa100 or PB100). The chemical structure of the polymer itself remained unchanged; hence this is a facile experimental system for solely investigating the effects of dynamic bonds on the mechanical properties of network polymers.