Acylhydrazine-based reticular hydrogen bonds enable robust, tough, and dynamic supramolecular materials

Supramolecular materials are widely recognized among the most promising candidates for future generations of sustainable plastics because of their dynamic functions. However, the weak noncovalent cross-links that endow dynamic properties usually trade off materials' mechanical robustness. Here, we present the discovery of a simple and robust supramolecular cross-linking strategy based on acylhydrazine units, which can hierarchically cross-link the solvent-free network of poly(disulfides) by forming unique reticular hydrogen bonds, enabling the conversion of soft into stiff dynamic material. The resulting supramolecular materials exhibit increase in stiffness exceeding two to three orders of magnitude compared to those based on the hydrogen-bonding network of analogous carboxylic acids, simultaneously preserving the repairability, malleability, and recyclability of the materials. The materials also show high adhesion strength on various surfaces while allowing multiple surface attachment cycles without fatigue, illustrating a viable approach how robustness and dynamics can be merged in future material design.

Automated summary

This article introduces a supramolecular cross-linking strategy based on acylhydrazine units, which allows hierarchical cross-linking of poly(disulfides) network and transforms the material from soft to stiff. The resulting material shows significantly increased stiffness while maintaining repairability, malleability, and recyclability. This research is of great importance for future material design.