ABSTRACT Conventional covalent and supramolecular crosslinks impose inherent trade‐offs between mechanical robustness and environmental adaptability in polymer networks. Mechanically interlocked junctions offer an alternative route by enabling topological motion without compromising structural integrity. Here, a modular approach is reported to construct topology‐engineered gels by copolymerizing 2‐hydroxyethyl acrylate (HEA) with doubly threaded (dt‐) pseudo4rotaxane crosslinkers, formed via the complexation of γ‐cyclodextrin (γ‐CD) and acrylate‐end‐capped pyrene derivatives. By tuning the HEA/water ratio in pre‐gel formulations, the supramolecular assembly can be shifted from dt‐ to singly threaded (st‐) entities, enabling access to gels with the same chemical composition but different architectures—dt‐slide ring network versus st‐polyrotaxane covalent network. The dt‐network exhibits solvent‐dependent fluorescence, swelling, and viscoelasticity that is not observed in either the st‐network or a covalent control gel. Mechanical testing of the bulk networks reveals that the dt‐network exhibits high extensibility (>1050% strain at break), strain rate‐dependent stiffening and rupture, and a favorable combination of high toughness and comparatively low hysteresis under cyclic deformation that is not observed in the networks lacking the dt‐architecture. Overall, these results establish a structure–property relationship dictated by crosslinking topology, demonstrating how dt‐interlocked motifs can encode both mechanical performance and environmental responsiveness in soft materials.
Oh et al. (2026) studied this question.