Temperature-Governed\nMicrostructure of Poly(vinyl\nalcohol) Hydrogels Prepared through Mixed-Solvent-Induced Phase Separation

The formation of phase-separated structures in hydrogels\nplays\na crucial role in determining their optical and mechanical properties.\nTraditionally, phase-separated hydrogels are prepared through a two-step\nprocess involving initial hydrogel synthesis followed by post-treatment.\nIn this study, we present an approach for temperature-governed phase\nseparation microstructure modulation in hydrogels, harnessing the\ncononsolvency effect. This method allows the phase-separated structure\nto develop during hydrogel synthesis, significantly simplifying the\npreparation process. Importantly, we found that the preparation temperature\nhas a substantial effect on the internal structure of the phase-separated\nhydrogel. We systematically investigated how the temperature influences\nthe phase structure, optical properties, and mechanical performance\nof these hydrogels. The resulting hydrogels demonstrate excellent\nmoisturizing and antifreezing capabilities. Additionally, the incorporation\nof sodium chloride imparts remarkable electrical conductivity to the\nhydrogels, making them suitable for strain sensing applications across\na wide temperature range.