Superhydrophobic surfaces by dynamic nanomasking and deep reactive ion etching

Abstract

This paper reports a study on fabricating superhydrophobic surfaces with microand nanohierarchical topography by dynamic nanomasking (DNM) and deep reactive ion etching (DRIE). In this study, thin layers of gold (Au) were sputtered on silicon (Si) wafers followed by annealing the samples in a conventional furnace to break the thin films into Au nanoparticles attached to the Si surfaces. These randomly distributed nanoparticles served as dynamic nanomasks during DRIE processes, in which sulphur hexafluoride (SF 6 ) and octofluorocyclobutane (C 4 F 8 ) were used as etching and polymerization gases, respectively. Surface topography and wetting properties of the samples were characterized by scanning electron microscopy (SEM) and a video-based optical contact angle meter (VOCAM). SEM images show that this technique created micro-sized craters with Au nanoparticles residing on the ridges of the microstructures. The largest water contact angle (WCA) obtained by this method is about 163 . The surface superhydrophobicity is attributed to the combination of micro-and nanohierarchical topography and surface polymerization.

Engineering a nanostructured “super surface” with superhydrophobic and superkilling properties

“…44 Here, due to the superhydrophobicity and low adhesion, the surface exhibits a similar behavior as the cicada wing 44 as the water droplet was unable to adhere and rolled off the surface (ESI, Video S1 †). The superhydrophobicity of the nanostructured surface is also facilitated by the C 4 F 8 gas discharges during the fabrication stage that deposits a hydrophobic Teon-like (polytetrauoroethylene, PTFE) passivation layer on the silicon material 45,46 as conrmed by the EDAX measurements (Fig. 1C).…”

Superhydrophobic surfaces produced by applying a self-assembled monolayer to silicon micro/nano-textured surfaces

“…Numerous methods of creating superhydrophobic surfaces have been reported by combining surface chemical and topography modifications, which include using aligned carbon nanotubes [10], electroless etching [11], electroplating [12], oxygen plasma etching [6], soft lithography imprinting [13], deep reactive ion etching [14], and many others. Each of these methods, however, has advantages and limitations.…”

Atmospheric synthesis of superhydrophobic TiO2 nanoparticle deposits in a single step using Liquid Flame Spray

“…(Borras et al, 2008;Feng et al, 2005) as well as combinations of different structures (Lai et al, 2009). Also other hydrophilic materials have been turned hydrophobic due to the creation of nanosized features using techniques such as deep reactive ion etching of e.g., Si surfaces (Song & Zou, 2007). The cause of the superhydrofobicity is claimed to be due to the so called lotus structure (Barthlott & Neinhuis, 1997).…”