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(ZrO 2 ) 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-ZrO 2 composite hydrogel was obviously improved due to that the ZrO 2 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.