Polymer gels have unusual properties, including the ability to absorb water in volumes hundreds of times greater than their own. For example, some hydrogels are capable of holding up to two kilograms of water per gram of dry gel. By changing the temperature or adding solvents, various desired properties can be achieved. This is why polymer gels are used in industry and biomedicine, including for the targeted delivery of medication, creation of artificial skin, children s toys, etc.
If you take a gel containing a high volume of solvent and gradually lower its temperature, when a certain temperature threshold is reached, there will be a sharp decrease in the volume of the gel and a large amount of liquid will be squeezed out of it the gel will collapse (contract).