Fig. 1. Schematic illustration of the preparation and modification of the hydrogel. (a) Common monomers (blue), anchor monomers (green) and clay nanosheets (crosslinker) were used to prepare the nanocomposite hydrogel. (b) All monomers and crosslinkers were homogeneously dispersed in water and, after the gelation process, the surface of the resulting hydrogel was covered with dimethylamino groups (active points). (c) Molecular formula of the photo-responsive molecule IBSP. (d) The modification process was realized through quaternization reactions. (e) Schematic illustration of the modification using IBSP as a modifier at the hydrogel/oil interface (with a limited thickness on the hydrogel).