Pre-Freezing-Assisted Wet Annealing Yields Mechanically Robust Hydrogels with Tunable Water Content

), outperforming conventional single-step hydrogels. Multiscale characterizations reveal enhanced crystallinity and intensified hydrogen bonding as key contributors. Notably, the water content is tunable (55-88%). These hydrogels exhibit superior fatigue and swelling resistance, along with low friction coefficients (0.03-0.15) under physiological conditions, promising for underwater load-bearing applications. This work establishes a versatile processing paradigm for engineering high-performance hydrogels via synergistic phase transition and macromolecular reorganization.