Multi-stimuli responsive supramolecular polymers and their electrospun nanofibers

A novel type of multi-stimuli responsive supramolecular polymer (MRSP) has been successfully constructed based on the self-assembly of heteroditopic macromonomers in a mixed solvent (CDCl₃ : CD₃CN = 2 : 1, v/v), which contain benzo-21-crown-7 (B21C7) host units and secondary ammonium salt guest moieties at each end of a poly(ε-caprolactone) (PCL) chain. Owing to the reversible host–guest complexation between B21C7 and the secondary ammonium salt, the resulting MRSPs exhibit multi-stimuli responsiveness to cations, pH, anions and temperature. More interestingly, nanofibers were facilely obtained via the solution electrospinning of a MRSP, which presented enhanced degradation behaviors in the presence of K⁺, Cl⁻, Et₃N, or heating, indicating a multiple stimuli-responsive nature.