Nanoconfined entanglement-enhanced phase separation enables tough and contractile ionogel fibers

Spider silk featuring strength-toughness synergy and rapid stimuli-responsiveness has inspired efforts to synthesize multifunctional fibers for advanced applications in soft robotics. However, replicating these incompatible properties remains hindered by the inadequate structural design which fails to integrate the rigid components and reversible interactions into a single system. Herein, we fabricate tough and responsive contractile ionogel fibers by nanoconfinement entanglement-enhanced phase separation strategy based on the bottlebrush-shaped composite slurry. The programmed assembly enables the multiscale energy dissipation, while efficient stress transfer and entanglement endow high network entropy elasticity and stable network integrity under hydration. Consequently, the produced fibers present an high tensile toughness of 1652.2 MJ · m^-3 while demonstrating a rapid supercontraction with a stroke of 76% and stress of 16.1 MPa upon hydration, yielding a high energy density of 236.4 J·kg^-1. By combining strong mechanical properties and supercontraction, this work paves a way for developing intelligent bio-inspired fibers.