Farag, Reem KHani,  Salma 2020-11-062020-11-062020-1010.1007/978-3-030-45135-6_4https://t.ly/ERrzThe use of synthetic crosslinked polymer gels has increased in recent years, due to their unique characteristics such as high mechanical strength, service life and water and oil swelling, as well as being biocompatible. They have been studied as promising candidates in various fields such as cardiac and oil sobrieties, contact lenses, cosmetics, drug delivery, tissue engineering, wound dressing, among others. This chapter provides general information on polymer gels, including defini- tion, classification, preparation methods and applications.en-USSwellingHydrophobic polymerGel applicationsHydrophilic polymerBook chapter