Fig. 4. Schematics and representative recovery process of the liquid-gas interface on submerged single level surfaces (top panel: (a)$\sim$(d)) and\\ hierarchically structured surfaces with nanoparticles-coated bottom (bottom panel: (e)$\sim$(h)). (a) shows the W state of the single level surface and (e) illustrates the nano-CB state of nanoparticles-coated hierarchically structured surface