Poly(N,N‐dimethylacrylamide) hydrogels obtained by frontal polymerization

Frontal polymerization (FP) has been used as an alternative technique for the preparation of poly(N,N‐dimethylacrylamide) hydrogels. Samples were synthesized in bulk, water, or dimethyl sulfoxide (DMSO), and the obtained materials were characterized and compared in terms of their yield, swelling behavior, thermal properties, and morphology. It was found that their features are dependent on the presence and type of the solvent used. Samples prepared in bulk are characterized by the lowest yields and the highest front temperatures (Tmax) and velocities (Vf), whereas those synthesized in water have the highest yields and the lowest values of Tmax and Vf. No significant differences have been found in terms of Tg among the three series of samples. By contrast, the reaction conditions influenced the porous morphology of the samples and, consequently, their swelling capability in water. The swelling ratio ranges from about 670–700% for some samples prepared in water up to 3500% for a sample obtained in DMSO, thus indicating that this parameter can be properly tuned by using the most suitable FP conditions.