Selective de-silanization assisted wettability patterning of aluminum surfaces

Hybrid surfaces with spatial wettability control are key for wider applicability in microfluidics, water harvesting, and inkjet printing. The patterned wettable surface is limited in its use on a broad scale due to the technological challenges of applying it to curved surfaces. In this study, we explore and demonstrate a desilanization technique to pattern hydrophilic spots on a superhydrophobic background. A simple chemical etching technique followed by functionalization with a low-surface-energy polymer yielded superhydrophobicity with contact angle of 178 degrees +/- 1 degrees and sliding angle \ 3 degrees on Al5052. Further, surface processing by fluorine-free desilanization for 5 min yielded hydrophilicity with contact angle of * 20 degrees +/- 1 degrees. To ensure the suitability of this technique in microfluidics, a microchannel surface with 300 lm channel width has been fabricated. Furthermore, the present study demonstrates the efficiency of simple wettability patterning on curved surfaces like Al cups and hollow pipes. Thus, a simple, cost-effective and time efficient methodology to fabricate wetting patterns on curved surfaces is proposed here. [GRAPHICS]

Automated summary

In this study, a desilanization technique is explored and demonstrated to pattern hydrophilic spots on a superhydrophobic background. The results show that this technique is suitable for microfluidics, water harvesting, and inkjet printing, and can be used to create wetting patterns on curved surfaces.