Adaptable Reversibly Interlocked Networks from Immiscible Polymers Enhanced by Hierarchy-Induced Multilevel Energy Consumption Mechanisms
Yang You, Min Zhi Rong, Ming Qiu Zhang
Abstract
The present work proposes a novel strategy to prepare reversibly interlocked networks with enhanced mechanical properties through hierarchy-induced multilevel energy consumption mechanisms. The core issue lies in the introduction of in situ inter-macromolecular ionic interactions among the component networks regardless of their miscibility, which is hard to be implemented in other materials. Traditional small-molecule contra-ions are no longer necessary accordingly. As revealed by the proof-of-concept transparent interlocked networks composed of immiscible cross-linked styrene–butadiene rubber (SBR) and polyethylenimine (PEI), the interlocking architecture and the inter-macromolecular ionic interactions are mutually promoted. The latter pulls the immiscible polymer chains together, favoring the formation of the former, while the former prevents the neighboring chains from separation and helps the complexation among the counterpart functional groups. Eventually, multilevel energy consumption mechanisms can be triggered under the applied force and the conventionally conflicting properties including strength, toughness, and creep resistance of the interlocked networks are remarkably increased at the same time. Moreover, the moisture sensitivity that used to accompany ionic interactions disappears, which broadens the application scope of the materials in practice. Owing to the included reversible Diels–Alder bonds and Schiff base, the SBR and PEI-based interlocked networks are self-healable and reprocessable and can even be unlocked producing the original single networks. It is anticipated that a versatile and facile platform technique may thus be developed for creating new polymeric materials with advanced multifunctionality.