Preparation of photodegradable polyacrylamide hydrogels via micellar copolymerization and determination of their phototunable elasticity and swelling behaviors

Polyacrylamide (PAAm) hydrogels were prepared by micellar copolymerization methodology in the presence of acrylamide and photo-decomposable hydrophobic crosslinker (diacrylated Irgacure-2959). After the synthesis of hydrophobically functionalized hydrogels via free radical copolymerization, gel samples were exposed to UV irradiation for different time intervals between 0 and 17 hours in aqueous medium. According to the results of swelling and compression tests, the physical properties of the hydrogels were altered by UV exposure time. The swelling degree of the hydrogels increased gradually with the irradiation time. Moreover, the 17 h irradiated hydrogel sample was entirely decomposed at the end of the swelling test. According to Scanning Electron Microscopy images, UV irradiated hydrogel samples exhibited an apparent degradation behavior.