Superhydrophobic micro/nano dual-scale structures

• Published in: Journal of nanoscience and nanotechnology Vol. 13; no. 2; p. 1539
• Main Authors: Zhang, Xiaosheng, Di, Qianli, Zhu, Fuyun, Sun, Guangyi, Zhang, Haixia
• Format: Journal Article
• Language: English
• Published: United States 01.02.2013
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2013.5986

In this paper, we present superhydrophobic micro/nano dual structures (MNDS). By KOH-etching of silicon, well-designed microstructures, including inverted pyramids and V-shape grooves, are first fabricated with certain geometry sizes. Nanostructures made of high-compact high-aspect-ratio nanopillars are then formed atop microstructures by an improved controllable deep reactive ion etching (DRIE) process without masks, thus forming MNDS. Resulting from both the minimized liquid-solid contact area and the fluorocarbon layer atop deposited during the DRIE process, the MNDS show a reliable superhydrophobicity. The contact angle and contact angle hysteresis are -165 degrees and less than 1 degrees, respectively. This superhydrophobicity of MNDS is very stable according to squeezing and dropping test, even in high voltage conditions with the electrowetting threshold voltage of -300 V. Therefore, this micro/nano dual-scale structure has strong potential applications to the self-cleaning surface and superhydrophobic micro/nano fluidics.