This study employs low‑field nuclear magnetic resonance (LF‑NMR) to probe water dynamics during the thermally reversible sol‑gel transition of agarose. T₂ relaxation measurements reveal a pronounced thermal hysteresis (~40 °C), with gelation occurring at ~30–35 °C upon cooling and melting at ~65 °C upon heating, demonstrating LF‑NMR as a powerful tool for characterizing phase transitions and molecular mechanisms in hydrogels.

Hydrogels are a class of polymer materials with broad application prospects. However, the high water content in most hydrogels limits their functionality to a narrow temperature range. Developing hydrogels with anti-freezing capabilities and reliable mechanical performance at low temperatures is a promising area of research.

Hydrogels are a type of highly hydrophilic three-dimensional network structure gel. They swell rapidly in water and can retain a large volume of water in this swollen state without dissolving.