Adaptable Interlocking Macromolecular Networks with Homogeneous Architecture Made from Immiscible Single Networks

Traditional interpenetrating polymer networks (IPNs) are not adaptable materials because the topological structure of the macromolecules cannot be changed, which limits their structural rearrangement, reprocessing, and recycling. Here in this work we present a strategy for preparing reversibly interlocking networks (RILNs) from two preformed immiscible polymer networks based on dynamic covalent chemistry. The frequently opening and closing of the single networks enabled by the exchange reactions of the embedded orthogonal dynamic covalent bonds and stronger intercomponent interaction mainly account for the formation of the interlocking topology architecture of the RILNs. The resultant RILNs are rather homogeneous, which not only possess stimulus-responsive adaptive performance like self-healing but also exhibit nonlinear improvement in static and dynamic mechanical properties. By taking advantage of the reversible bonding, more importantly, the RILNs can be unlocked reproducing the pristine single networks, and the relocking/unlocking cycling is allowed to proceed for multiple times, which are not available for IPNs as defined by their chemical nature. It is anticipated that the proposed methodology provides a new idea for producing multifunctional cross-linked polymers capable of repeated controlled degradation and regeneration.