Evaluation of pH/temperature double responsivity of copolymerized methacrylate-based networks: Solvent diffusion analysis with adjustable swelling kinetics

This study describes detailed investigation on dynamic swelling of cationic copolymeric hydrogels prepared by N,N-dimethylaminoethyl methacrylate (DMAEMA) and 2-Hydroxyethyl methacrylate (HEMA). The effect of pH on the copolymer structure and dynamic swelling kinetics of poly(N,N-dimethylaminoethyl methacrylate-co-2-Hydroxyethyl methacrylate) (P(DMAEMA-co-HEMA)) hydrogels was investigated under various experimental conditions. The pH as well as the temperature-dependent swelling results showed that the copolymeric hydrogels have strong desire to respond to the external temperature- and pH-stimuli. P(DMAEMA-co-HEMA) hydrogels exhibit excellent compositional and mechanical features as well as the unique tunable time-dependent swelling behavior. In methacrylate-based hydrogels, the hydrophilicity of monomers and the degree of crosslinking are not only the factors that determine the degree of swelling of resultant copolymeric hydrogels, the elastic property is a third factor that should be taken into account when discussing the swelling behavior. P(DMAEMA-co-HEMA) hydrogels possess tunable physico-chemical properties that can be adjusted by the changing the copolymer composition.