The World of Gel Technologies

The materials of interest in this brief review are primarily hydrogels which are polymer networks extensively swollen with water. Hydrophilic gels that are usually referred to as hydrogels are networks of polymer chains that are sometimes found as colloidal gels in which water is the dispersion medium. In this concern researchers over the years have defined hydrogels in many different ways. The most common of these is that hydrogel is a water-swollen and cross-linked polymeric network produced by the simple reaction of one or more monomers. Another definition is that it is a polymeric material that exhibits the ability to swell and retain a significant fraction of water within its structure but will not dissolve in water. Hydrogels have received considerable attention in the past 50 years due to their exceptional promise in wide range of applications. They possess also a degree of flexibility very similar to natural tissue due to their large water content.