Effect of porosigen and hydrophobic monomer on the fast swelling–deswelling behaviors for the porous thermoreversible copolymeric hydrogels

A series of porous thermoreversible copolymeric hydrogels were prepared from N‐isopropylacrylamide (NIPAAm) and hydrophobic monomers such as 2,2,3,3,4,4,5,5‐octafluoropentyl methacrylate (OFPMA) and n‐butyl methacrylate (BMA) and CaCO₃ or poly(ethylene glycol) 8000 (PEG8000) as porosigen by emulsion polymerization. The effect of hydrophobic monomers and porosigens on the fundamental properties, such as equilibrium swelling ratio, swelling kinetics, gel strength, crosslinked densities, etc., and fast swelling–deswelling behavior for the present copolymeric hydrogels were investigated. Results showed that the deswelling rates for the gels porosigened by CaCO₃ were more rapid than those gels foamed by PEG8000. Results also showed that the swelling rates for the gel foamed by CaCO₃ were higher than those for the gel foamed by PEG8000. At the same time, results also showed that the gels with OFPMA foamed by CaCO₃ exhibit a faster swelling–deswelling behavior than those gels with BMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3152–3160, 2006