Comprehensive mechanical reinforcement of hydrogels via network refinement.

Traditional single-network hydrogels are limited by trade-offs among key mechanical properties, such as elastic modulus and toughness, and are further compromised by structural defects introduced during synthesis. These constraints significantly hinder their performance in demanding applications. Here, we propose a network-refinement strategy using repeated crosslinking to achieve comprehensive mechanical reinforcement. Through network refinement, structural defects within polymer networks are progressively filled, and both the network homogeneity and effective chain density are improved. The reinforced hydrogels exhibit up to a 6-fold increase in elastic modulus, a 10-fold enhancement in fracture toughness, a 20-fold increase in tensile strength, and a 42-fold improvement in work of fracture, while maintaining high stretchability and negligible hysteresis under moderate deformation. This universal strategy provides an effective route to comprehensively enhance the mechanical properties of hydrogel-like materials, paving the way for robust soft materials in applications such as cardiac healing patches, load-bearing biomedical implants, and wearable electronics.