Nano-microstructured, superhydrophobic, and infrared transparent polytetrafluoroethylene/diamond films

Abstract

A self-assembled polytetrafluoroethylene (PTFE) nanostructure is deposited on microcrystalline diamond (MCD) films, by use of physical and chemical vapor deposition in a two-step process, to produce (fully) superhydrophobic surfaces: high water contact angle (static, 165±2 deg ), very low hysteresis (dynamic, ∼4 deg ), and associated sliding angle (1 deg 5 ′ ±15 ′ ), thus combining the diamond infrared transparency and self-cleaning properties. These are interpreted in light of Wenzel and Cassie-Baxter wetting models, associated with structural microscopy of nano-micro rough PTFE/MCD surfaces, and present a promising perspective for self-cleaning infrared optics applications.