Fast-responsive macroporous hydrogels

In 1960, the history of synthetic hydrogels witnessed the rst generation of its application in the biomedical eld. Wichterle and Lim developed the rst biomaterial hydrogel based on 2-hydroxyethyl methacrylate [1]. Since then, more and more hydrogels have been introduced with biomedical and pharmaceutical applications. Interestingly, all these developments have been more associated with the microstructure than chemical structure of these hydrogels. Hydrogel is generally a two-phase composite network of water and solid hydrogel. The hydrogel itself is a synthetic or natural-based hydrophilic polymer with the strong ability to interact intra-and intermolecularly with itself and with water. These two interactions are generally controlled by the composite makeup, in other words, the hydrogel structure and the amount of water inside the hydrogel. As a result, the composite is provided with properties that are known as swelling thermodynamics (capacity), swelling kinetics (rate), as well as mechanical properties.