Porous Semi-Interpenetrating Hydrogel Networks Based on Dextran and Polyacrylamide With Superfast Responsiveness

AAm was free-radical polymerized at various temperatures in the presence of N,/N'-methy-lenebisacrylamide as a cross-linker and dextran resulting in novel Dx/PAAm semi-IPNs. The structure and morphology of networks were investigated by means of FTIR, DSC, and ESEM. In comparison to the PAAm network, the interior network structures of the novel semi-IPNs prepared at -18 degrees C exhibit a heterogeneous morphology consisting of pores of sizes about 80 mu m, while those formed at +5 and +25 degrees C have pores with sizes about 3 mu m. The Dx/PAAm semi-IPNs exhibited higher swelling ratios, than those without Dx, irrespective of the gel preparation temperature. Moreover, Dx/PAAm semi-IPN hydrogels formed at -18 degrees C attain the equilibrium state in water within 15 s.