Swelling Behavior Study of Physically Crosslinked Gelatin Hydrogels

A series of physically crosslinked gelatin networks were prepared and the effects of salt, pH, temperature and polymer concentration on the swelling properties of gelatin hydrogels were studied in detail. The swelling equilibrium of the gelatin networks can be described as a simple superposition of polyelectrolyte behavior and polyampholyte behavior. It was found that high temperature, low gelatin concentration and deviation from the isoelectric point can promote the swelling of the polymer networks. Moreover, the swelling kinetics of gelatin hydrogels at different salt concentration solutions was also investigated. It is found that the rate of swelling of gelatin could be described by a second-order rate equation, which indicated that the structure of the gelatin networks is homogenous.