Three kinds of polyisopropylacrylamide hydrogels (HNB) with 5~80 m of pore size were prepared by using surfactants Brij 52/56/58 with same hydrophobic alkyl chain C16H33 and different hydrophilic poly(ethylene oxide) (PEO

(CH2CH2O)n=2

10

20) segments as template.The results show that the hydrophobicity increases with decreasing n values.The Brij aqueous solutions with different n values show clear liquid crystal texture at a concentration of 15 wt%.At t=4 and 7 min

the transmittance of HNB58 and HNB56 pre-polymerized liquids decreases to 3.3~3.5.However

the transmittance of HNB52 pre-polymerized liquid keeps at 3.5 throughout the reaction time.The HNB58 hydrogel using Brij 58(n=20) as template shows numerous pores

and the size is 5~10 m.The HNB52 hydrogel using Brij 52(n=2) as template shows layered pore structure

and the maximum swelling ratio is 6.9 g/g.The HNB56 hydrogel using Brij 56(n=10) as template presents honeycombed state

having largest pore size from 40 to 80 m.In addition

the maximum swelling ratios of HNB56 is 7.9 g/g

and water loss rate exceeds 80% at 37℃ and 20 min.Since the template action of Brij

the volume phase transition temperature (VPTT33℃) of HNB hydrogels keeps almost the same in spite of the difference of n value

but the endothermic peak area becomes wider with increasing n value.