Tailoring the wettability of patterned silicon surfaces with dual-scale pillars: From hydrophilicity to superhydrophobicity

► A convenient yet effective method of combining reactive ion etching and catalyzed etching to prepare silicon surface with micro-nano dual-scale pillars is presented. ► 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.