Strong and Ultra‐Tough Supramolecular Hydrogel Enabled by Strain‐Induced Microphase Separation

Abstract Architected hydrogels are widely used in biomedicine, soft robots, and flexible electronics while still possess big challenges in strong toughness, and shape modeling. Here, inspired with the universal hydrogen bonding interactions in biological systems, a strain‐induced microphase separation path toward achieving the printable, tough supramolecular polymer hydrogels by hydrogen bond engineering is developed. Specifically, it subtly designs and fabricates the poly (N‐acryloylsemicarbazide‐co‐acrylic acid) hydrogels with high hydrogen bond energy by phase conversion induced hydrogen bond reconstruction. The resultant hydrogels exhibited the unique strain‐induced microphase separation behavior, resulting in the excellent strong toughness with, for example, an ultimate stress of 9.1 ± 0.3 MPa, strain levels of 1020 ± 126%, toughness of 33.7 ± 6.6 MJ m −3 , and fracture energy of 171.1 ± 34.3 kJ m −2 . More importantly, the hydrogen bond engineered supramolecular hydrogels possess dynamic shape memory character, i.e shape fixing at low temperature while recovery after heating. As the proof of concept, the tailored hydrogel stents are readily manufactured by 3D printing, which showed good biocompatibility, load‐bearing and drug elution, being beneficial for the biomedical applications. It is believed that the present 3D printing of the architected dynamic hydrogels with ultrahigh toughness can broaden their applications.