A novel temperature- and pH-sensitive graft copolymer hydrogel composed of 2-(N,N- dimethylamino)ethyl methacrylate (DMAEMA) and N-isopropylacrylamide (NIPAM) was synthesized by macromonomer technique and free radical solution polymerization. The composition and surface morphology of the hydrogels were investigated by means of Fourier transform infrared spectroscopy and scanning electron microscopy. The deswelling and swelling kinetics of the graft copolymer hydrogels in different pH media at different temperatures demonstrate that the graft copolymer hydrogels have temperature and pH double sensitivities. Compared with conventional polyacrylic acid hydrogels, the pH sensitivity of synthesized hydrogels is contrary and the hydrogels are in swollen state in acid medium. The P(DMAEMA-g-NIPAM) hydrogels have a faster deswelling rate at 55 ℃, and the more the PNIPAM graft chain contents in the hydrogels are, the faster the deswelling rate of the hydrogels is.

Key words: 2-(N,N-dimethylamino)ethyl methacrylate, N-isopropylacrylamide, graft copolymer hydrogel