Reversibly Interlocking of Immiscible Covalent Adaptive Networks in Solid State: A Paradigm for Enhancing Interfacial Interaction of Multicomponent Polymer Systems

The authors of this work propose the construction of reversibly interlocked macromolecular networks (RILNs) at the interface between immiscible polymers to address the common challenge arising from compounding different polymers together. The proof-of-concept model system is made by stacking cross-linked polyether and styrene–butadiene block copolymer, which, respectively, contain reversible Schiff base and Diels–Alder (DA) bonds. By taking advantage of the synergy between the topological rearrangement of the dynamic networks and migration of the pre-embedded zinc ion catalyst, interdiffusion and interlocking of the temporarily de-cross-linked macromolecular chains can be purposely synchronized. Consequently, the envisaged interfacial RILNs with decent mechanical properties are successfully prepared in the solid state, which is an advancement over traditional RILNs that have to be made with the assistance of solvent. The resulting interfacial binding is tight and reversible because of the massive chain entanglements in the interfacial region and the degradability of dynamic networks as well. It is anticipated that the methodology discussed in the paper would hopefully be developed into a facile technique for the fabrication of high-performance polymer blends regardless of the miscibility of the raw materials.