Preparation and properties of cryogels based on poly(sulfopropyl methacrylate) or poly(sulfobetaine methacrylate) with controlled swelling

We report the synthesis and characterization of interconnected macroporous network structures of poly(sulfopropyl methacrylate) or poly(sulfobetaine methacrylate) under cryogenic conditions. It has been shown that since the gels obtained from PSPM and PSBMA homopolymers have poor mechanical properties, the gels were synthesized in the presence of comonomers (2-hydroxyethylmethacrylate (HEMA) and vinyl acetate (VA)) and a crosslinking agent (N,N’-methylene-bis-acrylamide, MBA). Preparation of PSBMA-based cryogels requires a 5-fold increase in the concentration of N,N,N’,N’-tetramethylethylenediamine (TMEDA). Morphology, specific surface area, and mechanical properties of cryogels obtained after freeze-drying were dependent on initial freezing temperature and the nature of the functional comonomers in polymerization mixture. The swelling behaviors of copolymer-based cryogels were investigated in water, saline and formic acid solutions and compared with those of chemically crosslinked PSPM and PSBMA cryogels.