Fabrication and characterization of interpenetrating network hydrogels based on sequential amine‐anhydride reaction and photopolymerization in water

Abstract Herein, interpenetrating network (IPN) hydrogels were successfully prepared for the first time through integrating two cross‐linking reactions in water in one pot, including amine‐anhydride reaction and subsequent photopolymerization. First, the polymer containing anhydride groups was prepared via free radical copolymerization of maleic anhydride and acrylamide. Second, the as‐prepared polymer was dissolved in water with polyacrylamine hydrochloride, N ‐isopropylacrylamide, polyethylene glycol dimethacrylate, 2‐acrylamido‐2‐methylpropanesulfonic acid, and photoinitiator to obtain a homogeneous transparent solution. Third, the mixed solution was put in water bath of 50°C for 1 h to obtain the first network via the amine‐anhydride click reaction. Afterward, the second network was formed by photopolymerization. Finally, the swelling and drug release behavior of the hydrogels were studied with isoniazid as a model drug. The results show the IPN hydrogel possesses pH and temperature sensitivity and their controlled‐release behavior can be tuned via adjusting pH and temperature. In view of the advantages of amine‐anhydride reaction and photopolymerization, the strategy described here is of significance for the preparation of IPN hydrogel.