Fabrication of template with dual-scale structures based on glass wet etching and its application in hydrophobic surface preparation

Template-based methods are a commonly used way to prepare superhydrophobic surfaces, in which, one of the critical issues, is template fabrication. In this work, a template with a dual-scale hierarchical structures fabrication method is investigated, in which, using the Cr and photoresist as etching mask, the fused silica glass substrate is etched in a buffered hydrofluoric solution. Optical photos and atomic force microscopy (AFM) scans show that the excellent ordered and uniform microstructures with a feature size less than 4 μm combining with the nanostructures with a feature size of about 20-30 nm on the etched surface have been fabricated, indicating hierarchical structures being obtained. Then the template with dual-scale structures is used as a master template and experiments of pattern transferring to PDMS and photoresist by cast moulding and by imprint lithography, respectively, have been conducted. The duplicating fidelity is characterised through optical photos and AFM scans. The contact angles of water on various fabricated surfaces are characterised and the influence of the surface roughness on wettability has been discussed.