Intramolecular Cross-Linking: Addressing Mechanochemistry with a Bioinspired Approach

Many of the attractive properties in polymers are a consequence of their high molecular weight and therefore scission of chains due to mechanical stress leads to deterioration in properties and performance. Here, we mimic the architecture of immunoglobulin-like domains of Titin, whose structure directs mechanical force towards the scission of sacrificial intramolecular hydrogen bonds, absorbing mechanical energy while unfolding. Intramolecular cross-links are systematically added to synthetic polymer chains, slowing down mechanochemical degradation to the point where the chains become virtually invincible to shear in solution. The kinetics of the mechanochemical reactions supports this hypothesis, as the polymer properties are maintained while high rates of mechanochemistry are observed. Our results demonstrate that polymers with intramolecular cross-links can be used to make solutions which, even under severe shear, maintain key properties such as viscosity.

This paper was published in Angewandte Chemie International Edition: