On the near-infrared light-responsive and mechanical properties of PNIPAM-based nanocomposite hydrogels

Smart near-infrared (NIR) light-responsive poly N-isopropylacrylamide (PNIPAM) nanocomposite hydrogels were prepared by incorporating sparse chemical cross-linking of small molecules. The thermo-sensitive, NIR light-responsive, toughness and strength of the pure PNIPAM, PNIPAM-Graphene oxide(GO) and PNIPAM-GO-Zirconia(ZrO2) hydrogels were invesitgated. The introduction of GO induced PNIPAM the transformation from the thermosensitive to NIR light-responsive, and the oxidized groups of GO nanosheets could physically cross-link the PNIPAM chains to increase the toughness of the hydrogel networks. The loading capability and penetration resistance of PNIPAM-GO-ZrO2 composite hydrogel was obviously improved due to that the ZrO2 powder stabilize the hydrogel networks and strengthen the hydrogen bond interaction with the amide groups of PNIPAM chains compared with that of the pure PNIPAM and PNIPAM-GO, respectively.