Interpenetrating network (IPN) hydrogels composing of poly(N-isopropylacrylamide) (PNIPAAm) using inorganic clay (Laponite XLS) as physically crosslinking agent and polyacrylamide (PAAm) chemically crosslinked by N，N′-methylenebis(acrylamide) (MBAAm)

were prepared by ultraviolet irradiation polymerization.The structure of resultant IPN hydrogels was successfully characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM); the water retention at 50℃ was measured gravimetrically; dependence of storage modulus on temperature and phase transition behavior were investigated by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC)

respectively.The results show that this kind of IPN hydrogels are temperature-sensitive

and

compared with inorganically crosslinking PNIPAAm hydrogels

these IPN hydrogels exhibit enhanced storage modulus and ultrafast response rate

such as losing water of 90% within 10 min because of the porous structure which provides the waterreleasing channel; by incorporation of PAAm network

the phase transition of PNIPAAm hydrogels is weakened

but the lower critical solution temperature (LCST) is increased.