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Highlights: [•] Increasing the height and decreasing the space of the micro-rod may result in Cassie wetting state. [•] Decreasing the height and increasing the space of the micro-rod may result in Wenzel wetting state. [•] A suspended wetting state model due to wall scallops was proposed. [•] The wetting state transition was interpreted by intruding height, de-pinning and sag mechanism. [ABSTRACT FROM AUTHOR]

Abstract: Wettability tailoring of patterned silicon surface has great potential in fields producing integrated circuits, solar cells, sensors, detectors, and micro/nano electromechanical systems. The present paper presents a convenient yet effective method of combining reactive ion etching and catalyzed etching to prepare silicon surface with micro–nano dual-scale pillars. The experimental results indicate that the hydrophilic surface transformed to a superhydrophobic surface when micro–nano dual-scale pillars were formed. The surface preserved superhydrophobicity even when the geometric parameters of the micropillars were changed. Overhangs of water drops on steep micro–nano dual-scale pillars result in superhydrophobicity. This method offers a new way for tailoring the wettability of patterned silicon surfaces. [Copyright &y& Elsevier]