Swelling behavior of gelatin-ionic liquid functional polymers

In this work, hydrogels obtained by mixing gelatin with ionic liquids (ILs) are prepared. Two different ILs, [emim][EtSO₄] and [bmim][N(CN) ₂], are used to prepare hydrogels with different amounts of starting water and phosphate buffer content, which are used after a maturation period. The percentage of swelling in water and phosphate buffer, swelling and diffusion parameters are investigated in thin-film polymers (1 × 1 cm²; 1-mm thick) with different maturation times and at temperatures ranging from 4 to 37 °C. [emim][EtSO₄] polymers show a moderate (100% weight increase) but quick swelling that reaches 80% of the equilibrium within 30 min. They are liquefied and dissolved at temperatures above 25 °C. [bmim][N(CN)₂] polymers with short maturation times exhibit a similar behavior to the former, but more mature hydrogels register a very small swelling, abnormal kinetics and are more resistant to higher temperatures.