Engineering Cartilage-Like PVA Hydrogels: Dual-Stage Crystallization Kinetics Regulations Overcome the Strength-Water Content Trade-Off.

The development of PVA hydrogels for cartilage repair is limited by the challenge of simultaneously combining high mechanical strength with high water content. To address this, a "Dual-Stage Temperature-Controlled Crystallization Quenching Method" is proposed. The approach precisely regulates crystallization kinetics, enabling meticulous control over the gel network topology. The obtained hydrogel achieves a water content of 83.41% ± 0.51%, a tensile strength of 2.68 ± 0.14 MPa, and a compressive modulus of 0.53 ± 0.02 MPa, exceeding machine learning-predicted thresholds for each property by over 300%. This performance is attributed to a uniform, isotropic network of refined crystallites, as revealed by multiscale analysis, which facilitates homogeneous stress distribution and efficient energy dissipation. Furthermore, the hydrogel possesses a low friction coefficient, biomimetic porosity, and excellent chondrocyte compatibility. This work provides an advanced cartilage repair material and establishes a novel thermodynamic paradigm for polymer gel design through crystallization kinetics regulation.