Highly biodegradable, thermostable eutectogels prepared by gelation of natural deep eutectic solvents using xanthan gum: preparation and characterization

As a possible alternative to hydrogels, eutectogels are formed by gelling natural deep eutectic solvents (NADESs) that may be closer to the intracellular environment than pure water. This study successfully prepared highly biodegradable and thermostable eutectogels based on polysaccharides and NADESs, and studied the possible mechanism of eutectogel formation. The results show that these eutectogels displayed excellent thermostability as both the G′ and G′′ values remained constant in the temperature range of 60–110 °C, and the weight of the eutectogels remained almost unchanged when held at 80 °C for 10 hours. Similar to the formation of xanthan gum-based hydrogels, water addition and annealing treatment are necessary for the preparation of xanthan gum-based eutectogels. XRD, DSC and FT-IR results show that the existence of xanthan gum affects the original hydrogen bonding network of the NADESs, which further indicate that the hydrogen bond interaction between xanthan gum and NADESs is an important cause of eutectogel formation and changes in gel properties. Rheological results show that the eutectogel is a weak gel with excellent thermostability and structure recovery. As it is more stable than hydrogels and greener than ion gels, the polysaccharide-based eutectogel is expected to be widely used in the fields of food, medicine and materials.