Swelling, Elasticity and Spatial Inhomogeneity of Poly(N,N-dimethylacrylamide) Hydrogels Formed at Various Polymer Concentrations

The equilibrium swelling degree, modulus of elasticity and the spatial inhomogeneity of poly(N,N‐dimethylacrylamide) (PDMAAm) hydrogels were investigated over the entire range of the initial monomer concentration. The degree of dilution of the networks after their preparation was denoted by ν 20, the volume fraction of crosslinked polymer after the gel preparation. The linear swelling ratio of the gels increased linearly with increasing ν 20. Depending on the value of ν 20, three different gel regimes were observed: (1) For ν 20