Hydrogen Bond and Hydrophobic Interaction Reinforced Tough and Antiswelling Hydrogels via Polymerization-Induced Microphase Separation

Polymerization-induced microphase separation strategy offers an effective approach for designing hydrogels with microphase-separated structure. In this study, a kind of microphase-separated hydrogels was fabricated by copolymerizing histidine methacrylamide and methacrylic acid monomers. Spontaneous microphase separation occurred during the polymerization process, which was driven by the strong hydrogen bonding interactions between imidazole and carboxyl groups, stabilizing by the hydrophobic interactions of methyl groups. The microphase-separated hydrogels exhibited significantly enhanced mechanical properties, achieving stiffness of 67 MPa, tensile strength of 2.2 MPa, toughness of 8.3 MJ/m³, fracture energy of 7.0 kJ/m², and superior energy dissipation capabilities. These hydrogels also exhibited remarkable antiswelling performance across a broad pH range (pH 3-11). Notably, the microphase-separated hydrogels remained in a glassy state at room temperature. Moreover, the hydrogels displayed excellent cytocompatibility. This study provides valuable insights into the design of microphase-separated hydrogels, paving the way for their practical applications in biomedical engineering.