A versatile and simple rectangular-topology strategy enables robust hydrogels

High‑strength, tough hydrogels are urgently needed for biomedicine and soft robotics, yet single‑network architectures suffer from an inherent trade‑off between mechanical robustness and high water content. Herein, we propose a rectangular topological network (RN) composed of rectangular motifs in a single-network hydrogel via stoichiometric crosslinking of long and short polymer chains. This architecture achieves a high elastic modulus via dense intermolecular hydrogen bonds while maintaining large mesh sizes. Driven by a strain-induced hardening mechanism, the hydrogel achieves a simultaneous increase in strength and toughness. Successful fabrication using two crosslinkers demonstrates broad applicability. A representative PEG‑based RN hydrogel exhibits a Young’s modulus of 21.97 MPa, a toughness of 31.04 MJ·m−3, and a tensile strength of 7.72 MPa. Thus, we show that this facile and versatile RN strategy offers a route for high‑energy dissipation and can be extended to other platforms. Tough hydrogels have potential in a range of applications, but balancing mechanical robustness and high water content is challenging. Here, the authors report the development a rectangular topological network for high mechanical robustness in a single network hydrogel.