Temperature- and pH-sensitive nanocomposite gels with semi-interpenetrating organic/inorganic networks

An intelligent nanocomposite hydrogel with a semi-interpenetrating organic/inorganic network was synthesized through in situ free-radical polymerization of NIPA in the presence of an inorganic clay and linear PAA. The resulting semi-interpenetrating nanocomposite gels (sI-NC gels) showed mechanical and swelling/deswelling properties greatly superior to those of other PNIPA/PAA hydrogels. The sI-NC gels repeatedly changed their swelling behavior in response to both temperature and pH while retaining their remarkable mechanical properties. The structure and homogeneity of these networks were studied and related to the properties of sI-NC gels and the hydrogen bonding interactions among the constituents.