Mechanically robust and dynamic supramolecular polymer networks enabled by [an]daisy chain backbones

Supramolecular polymer networks (SPNs) have garnered significant research interest due to their dynamic properties. However, while current developments primarily focus on managing supramolecular crosslinks, the role of polymer backbones—equally crucial to SPN properties—has not yet been sufficiently explored. Herein, we utilize mechanically interlocked [an]daisy chain as backbone to prepare a class of SPNs, where the force-induced motion of successive mechanical bonds toughens and reinforces the networks. In specific, the [an]daisy chain backbones connect with polynorbornene chains through quadruple H-bonding in the SPN networks. Compared to the control with non-slidable backbone, The representative SPN-2 exhibits a robust feature in tensile tests with high maximum stress (14.7 vs. 7.89 MPa) and toughness (83.8 vs. 48.6 MJ/m³). Moreover, it also has superior performance in energy dissipation benefitting from the [an]daisy chain backbones as well as supramolecular crosslinks. Additionally, the SPN-2 displayed exceptional self-healing and reprocessing capabilities due to their dynamic quadrable H-bonding crosslinkers. These findings demonstrate the untapped potential of [an]daisy chain as a polymer skeleton to develop SPNs and open the door to design mechanically robust supramolecular materials with diverse smart functions.