title: Superhydrophobic micro/nano dual-scale structures.
abstract: 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.
authors: Science and Technology on Micro/Nano Fabrication Lab, Peking University, Beijing 100871, China.
authors: Xiaosheng
authors: X
authors: Zhang
authors: Qianli
authors: Q
authors: Di
authors: Fuyun
authors: F
authors: Zhu
authors: Guangyi
authors: G
authors: Sun
authors: Haixia
authors: H
authors: Zhang