Fig. 6.

Visible-light-controlled reversible switching of the surface wettability. a Photographs of the porous silica coating before and after modification with Ru-H₂O. b Scanning electron microscope (SEM) image of the Ru-H₂O-modified porous silica coating. Scale bar is 400 nm. c Schematic illustration of the reversible hydrophilic-to-superhydrophobic transitions based on visible-light-controlled metal–ligand coordination. d Change in the static contact angles when the ligands on the surface were interconverted between MTE and HFDMS. Blue squares indicate MTE ligands on the surface. Purple squares indicate HFDMS ligands on the surface