Superhydrophobic 3D Porous PTFE/TiO2 Hybrid Structures

Combining hard‐templating and infiltration processes, micro‐ and nanoscale topography induced by 2D assembling of TiO2 nanoparticles is extended to 3D TiO2. By applying an ultrathin and highly conformal polytetrafluoroethylene (PTFE) layer on prepared 3D TiO2 via initiated chemical vapor deposition (iCVD), a robust superhydrophobic bulk material (3D PTFE/TiO2) is achieved. A comparative study is conducted to reveal the stability of Cassie state for 3D PTFE/TiO2 against the external pressure by squeezing a water droplet between 2D and 3D PTFE/TiO2 structures. The use of such a stable 3D superhydrophobic PTFE/TiO2 structure for the controlled release medium is shown by a case study. Superhydrophobic bulk materials are promising candidates for various applications including water treatment, filtering, and controlled delivery systems. In this Communication, it is presented how to turn a superhydrophilic 3D TiO2 porous structure into a water repelling superhydrophobic bulk material by initiated chemical vapor deposition.