Hydrogels are a group of materials that consist mainly of water and are held together by three-dimensional polymer chains. Due to their high water content, they are in a constant exchange with their environment. They shrink when dried and expand in humid environments. They are therefore buffer materials whose properties are constantly changing.
This makes hydrogels interesting materials for overheated cities because they can exert a cooling effect via the evaporation of the water they contain. In biology and medicine, hydrogels could be interesting for tissue applications.
