Fabrication of superhydrophobic surface using surface texturing with nano-sized structure and PTFE film

Abstract

We developed a superhydrophobic surface using surface texturing with nano-sized structure and polytetrafluoroethylene (PTFE) film deposition. The properties of superhydrophobic surface were investigated using water contact angle, root mean square (RMS) roughness, and X-ray photoelectron spectroscopy (XPS). The contact angle of a water droplet was greater than 150°, which means extremely low wettability is achievable on superhydrophobic surfaces. For nano-sized structure, we carried out two step etching process using reactive ion etching (RIE) in a large pyramid substrate by potassium hydroxide (KOH) solution. Metal mesh installed RIE etched silicon substrate using SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> and O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas. PTFE films were deposited by conventional RF magnetron sputtering. This process is applicable for stable superhydrophobic and self-cleaning surfaces due to hierarchical structures formed silicon wafer etched by RIE technique.