he wettability of the one-dimensional (1D) nanostructures was tuned from superhydrophilic to superhydrophobic by simply modifying their surface with fluorinated phosphazene. We showed two extreme wetting regimes, perfect wetting and non-wetting, on the same surface without altering its topography. This perfectly hydrophobic surface may find applications in medicine/ biology, including blood contacting surfaces, cell separation sorting and diagnostic applications. By applying proper masking technology, extreme wetting contrasts can be achieved by keeping the surface topography identical, which is of interest for various microfluidic and membrane applications.

Fig 1. A schematic presentation of the preparation of the superhydrophilic and superhydrophobic surfaces.

Combining hard-templating and infiltration processes, micro- and nanoscale topography induced by two-dimensional (2D) assembling of TiO₂ nanoparticles is extended to three-dimensional (3D) TiO₂ structure. 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. This approach leads to various controlled release mechanism including drug release.

Video 1. Controlled release mechanism for possible drug delivery applications.

Selected publications

O.C. Aktas, S. Schröder, S. Veziroglu, M.Z. Ghori, A. Haidar, O. Polonskyi, T. Strunskus, K. Gleason, F. Faupel, Superhydrophobic 3D Porous PTFE/TiO₂ Hybrid Structures, Adv. Mater. Interfaces. 6 (2019) 1801967.

A. Haidar, A.A. Ali, S. Veziroglu, J. Fiutowski, H. Eichler, I. Müller, K. Kiefer, F. Faupel, M. Bischoff, M. Veith, O.C. Aktas, H. Abdul-Khaliq, PTFEP–Al₂O₃ hybrid nanowires reducing thrombosis and biofouling, Nanoscale Adv. 1 (2019) 4659–4664.