High-performance PVA hydrogels with high strength, fatigue resistance, and low hysteresis via high-temperature stretching-assisted post-rehydration

Polyvinyl alcohol (PVA) has emerged as a fundamental matrix material for constructing mechanically robust and fatigue-resistant hydrogels, owing to its unique combination of excellent biocompatibility, outstanding chemical stability, remarkable hydrophilicity, and cost-effectiveness. As physically cross-linked single-component systems, mechanical properties of PVA hydrogels are predominantly governed by two structural parameters: crystallinity and orientation of the crystallites. Herein, we propose a facile “high-temperature stretching-assisted post-rehydration” strategy to fabricate high-performance PVA hydrogels through simultaneous enhancement of crystallinity and crystalline alignment. Remarkably, the developed method successfully integrates multiple traditionally incompatible mechanical properties, including high tensile strength (30 MPa), exceptional fracture energy (22.4 kJ/m 2 ), superior fatigue resistance (9100 J/m 2 ), low hysteresis (8.3 %), and characteristic J-shaped stress-strain behavior.