or partially removed, superhydrophobicity properties vanish easily. Such 2D surfaces provide a metastable superhydrophobic state since the limited entrapped air in such surfaces disappears quickly in contacting with water and the surface gets completely wetted within a short time. In contrast, 3D structures maintain trapped air at the surface and through whole bulk. [7] These kinds of structures may provide a stable and long-running superhydrophobicity since penetrating water will meet continuously with a fresh trapped-air barrier. It is essential to extend the surface topographies responsible for superhydrophobicity into the bulk by creating both roughness and low surface energy to achieve superhydrophobic 3D materials.Herein, a commercially available polyurethane (PU) foam was utilized as the sacrificial hard template to infiltrate TiO 2 nanoparticles in its interstitial pores. By simply burning out PU template and sintering at 850-900 °C, a 3D TiO 2 skeleton (forming inner and outer macropores) was achieved by 2D assembling of TiO 2 nanoparticles through the whole bulk. By combining macrolevel pores and the micro-/nanostructured topography, a 3D high surface roughness was achieved (Figure 1a; Figure S1, Supporting Information). The prepared TiO 2 slurry was also applied to planar quartz substrates by double-doctor blade coating technique to achieve micro-/nanostructured 2D TiO 2 (Figure 1a; Figure S2, Supporting Information). Afterward, initiated chemical vapor deposition (iCVD) was carried out to coat 2D and 3D TiO 2 homogenously with a thin layer of polytetrafluoroethylene (PTFE) while conserving the inner micro-and nanotopography (as shown schematically in Figure 1b). iCVD allows coating various types of substrates varying from simple 2D to complex 3D structures with a high conformity (without altering topographic details of the pristine structure). [8] After coating a thin layer of PTFE, 3D TiO 2 showed an extraordinary superhydrophobicity.3D TiO 2 has a porous structure with the pore size of ≈100-150 µm (Figure 2a) and exhibits approximately the same micro-and nanoscale structures with 2D TiO 2 surface prepared for the comparison by the well-established doctor blade technique. [9] While 2D surface was composed of micro/nano hierarchical porous texture, 3D surface consists additionally macropores (Figure 2a). Clearly micro-and nanoscale roughness was provided through the whole bulk in 3D TiO 2 . Following the iCVD step, we did not observe any significant change in the morphology of both 2D and 3D TiO 2 . This indicates that the deposited PTFE layer was extremely thin and highly conformal. Figure 2b shows the X-ray photoelectron spectroscopy (XPS) survey spectra of the uncoated and coated 3D TiO 2 . Simply Combining hard-templating and infiltration processes, micro-and nanoscale topography induced by 2D assembling of TiO 2 nanoparticles is extended to 3D TiO 2 . By applying an ultrathin and highly conformal polytetrafluoroethylene (PTFE) layer on prepared 3D TiO 2 via initiated chemical vapor deposition (iC...