The preparation and characteristic of robust inorganic/organic IPN nanocomposite hydrogels with fast response rate

In order to prepare a robust thermosensitive hydrogels with ultrarapid response rate, the –Si–O– network was incorporated into the first clay cross-linked poly(N-isopropylacrylamide) network by the simultaneous hydrolytic polycondensation of tetramethoxysilane (TMOS); the two-step freezing polymerization technique was used in polymerization process for guaranteeing the very fast response rate of gels. The properties of resulting hydrogels (T-NC gels) including mechanical properties, hydrophily, swelling and response behavior show an obvious dependency on the content of added TMOS. With the increase of added TMOS, the more integrated and high-density –Si–O– network was formed in gels, which makes the gels become more robust with higher strength and modulus, while the swelling ratio and response rate decreases due to the lapped effect of increased network density and hydrophobicity. Interestingly, T-NC gels show better volume stability than that of NC gels in shrinking process.