Insights into the Correlation of Cross-linking Modes with Mechanical Properties for Dynamic Polymeric Networks

Simultaneously introducing covalent and supramolecular cross-links into one system to construct dually cross-linked networks, has been proved an effective approach to prepare high-performance materials. However, so far, features and advantages of dually cross-linked networks compared with those possessing individual covalent or supramolecular cross-linking points are rarely investigated. Herein, on the basis of comparison between supramolecular polymer network (SPN), covalent polymer network (CPN) and dually cross-linked polymer network (DPN), we reveal that the dual cross-linking strategy can endow the DPN with integrated advantages of CPN and SPN. Benefiting from the energy dissipative ability along with the dissociation of host-guest complexes, the DPN shows excellent toughness and ductility similar to the SPN. Meanwhile, the elasticity of covalent cross-links in the DPN could rise the structural stability to a level comparable to the CPN, exhibiting quick deformation recovery capacity. Moreover, the DPN has the strongest breaking stress and puncture resistance among the three, proving the unique property advantages of dual cross-linking method. These findings gained from our study further deepen the understanding of dynamic polymeric networks and facilitate the preparation of high-performance elastomeric materials.