Tough and Fast‐Responding Fe³⁺‐Coordinated Poly (Acrylic Acid ‐N‐Isopropyl Acrylamide) Shape Memory Hydrogels

Abstract Hydrogels with programmable shape memory hold great promise for applications in soft robots, smart medical devices, etc., but the preparation of tough and fast‐responding shape memory hydrogels remains challenging. In this work, Poly (acrylic acid ‐N‐isopropyl acrylamide) (3:1)‐Fe³⁺ (P(AA‐NIPAM)(3:1)‐Fe³⁺) hydrogels are obtained by monomer copolymerization and ionic coordination, which exhibited tough mechanical properties with a maximum tensile strength of 2.48 ± 0.08 MPa and a maximum elongation of 338.5 ± 19.6%. The hydrogel also demonstrated a good shape memory effect, with the hydrogel curled into a spiral shape recovering to 71.1% ± 5.9% in 30 s under the swelling effect of water, and the convoluted structure recovering to 95% in 4 s. The shape memory hydrogels prepared based on this method will provide an important reference value for the development of higher performance shape memory hydrogels.