Self‐Polymerized Tough and High‐Entanglement Zwitterionic Functional Hydrogels

Zwitterionic hydrogels exhibit great potential in biomedical applications due to their antifouling properties and biocompatibility. However, the single-network structure of pure zwitterionic hydrogels leads to a low toughness and strength, limiting their application in biomedical fields. In this work, a high entanglement sulfobetaine methacrylate-dopamine hydrogel (SBMA-DA-PE) with low cross-linker content and high monomer concentration is prepared by using a dopamine oxidative radical polymerization method. Compared to a regular zwitterionic hydrogel, the SBMA-DA-PE hydrogel exhibits a 5-fold increase in tensile fracture stress and a 10-fold increase in compressive fracture stress. The SBMA-DA-PE hydrogel possesses excellent mechanical properties (the maximum compressive stress ≥4.85 MPa, the maximum compressive strain ≥90%). Besides, the non-covalent interactions between catechol or ortho-quinones within the SBMA-DA-PE hydrogel, combined with strong intermolecular electrostatic interactions, endow the SBMA-DA-PE hydrogel with great self-healing capabilities and fatigue resistance. The SBMA-DA-PE hydrogel demonstrates low swellability and possesses good antifouling properties. Furthermore, the good printability and conductivity of the tough SBMA-DA-PE hydrogel endows it with new possibilities for developing biological 3D scaffolds and electronic devices. Overall, this work provides new insights into the preparation of zwitterionic hydrogels with high mechanical strength and multi-functionality for biomedical applications.