Superhydrophobic and self-cleaning surfaces prepared from a commercial silane using a single-step drop-coating method

A simple and time-saving approach for preparing superhydrophobic and self-cleaning surfaces from a commercial silane, Octadecyltrichlorosilane (ODTS) is reported in this study. A solution of the silane was prepared by dissolving in hexane. Prior to film deposition, the substrates were treated with oxygen plasma etching to remove organic contaminants from the surface followed by immediate immersion in deionized (DI) water to form hydroxyl groups. A few drops of the prepared silane solution were then placed on the treated surface and allowed to dry under ambient conditions. The modified surfaces exhibited superhydrophobic behavior with advancing water contact angles (WCA) in the range 160–170° and the contact angle hysteresis (CAH) less than 10°. Surface characterization with scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed the presence of dual-scale roughness. Dust particles readily adhered to and were washed away with the rolling water droplets placed on the deposited film. Furthermore, the resulting surface was able to maintain these characteristics under the impact of a water jet. It should be mentioned that the demonstrated efficiency of this method makes it very feasible candidate for preparing self-cleaning surfaces for a variety of industrial applications.