The microgels with in terpenetrating polymer network(IPN) structure based on poly(N-isopropyl acrylami de)(PNIPAM) and poly(acrylic acid)(PAA) were synthesized by seed-emulsion poly merization

using redox initiator at room temperature and the less crosslinked P NIPAM microgels as seeds.The microgels were determined to be composed of PNIPAM and PAA by Fourier transform infrared spectrometer (FTIR)

and the IPN structur e in the microgels was confirmed by transmission electron microscopy(TEM).The results obtained by dynamic laser light scattering(DLLS) showed that the microg els had good pH/temperature dual stimuli responsiveness without any marked inter action.In the case of the pH of the aqueous media 5.5

the PAA component in t h e microgels had no effect on their volume phase transition temperature

but when the pH of the aqueous media was 4.0

their volume phase transition temperature was slightly decreased due to the formation of hydrogen bonds between PNIPAM and PAA.The pH stimuli responsiveness of the microgels was enhanced by the PAA co ntent within the microgels.