Mechanically adaptive and self-healable conductive hydrogels through dynamic hydrophobic networking and nanofibrillar...

Conductive and self-healable poly(acrylamide-co-stearyl methacrylate)@carboxylated cellulose nanofiber hydrogels were fabricated through one-pot free-radical polymerization within a dynamically associated polymer network. C-CNF incorporation strengthened the hydrogel through nanofibrillar reinforcement and hydrogen-bonding interactions, while StMA-derived hydrophobic associations formed within the DBSA-mediated micellar network provided reversible physical crosslinks. The C_1.50% hydrogel exhibited a fracture stress of ∼260.4 kPa, fracture strain of ∼528.4%, and toughness of ∼78.2 kJ m^-3, together with a distinct rate-dependent tensile response. Following damage, S_1.50% recovered ∼95.3% of its fracture strain and ∼83.2% of its toughness after 24 h. Time-resolved rheological measurements revealed progressive recovery of G' and G″ during the early healing period, consistent with gradual reconstruction of the viscoelastic network, while microscopic observations confirmed reconnection across the cut interface. Ionic conduction was re-established immediately upon cut/recontact, with S_1.50% retaining ∼88.9% of the initial conductivity before prolonged mechanical recovery. The hydrogel further exhibited stable strain-responsive behavior over low and high deformations, with gauge factors of ∼5.72 and ∼8.29 for C_1.50% and S_1.50%, respectively, response/recovery times of ∼350 ms, and cyclic durability over ∼500 cycles. Following healing, the reconstructed hydrogel retained distinct strain-dependent resistance responses and remained responsive to diverse human motions. These results demonstrate the capacity of dynamically associated p(AAm-co-StMA)@C-CNFs hydrogels to recover substantial mechanical and ionic sensing functionality after damage, supporting their application in self-healable strain sensors, wearable monitoring, and flexible human-machine interfaces.