Nanosecond laser textured superhydrophobic/superhydrophilic patterned surface for efficient fog harvesting

Abstract

Fresh water shortage is considered as growing global problem due to increasing climate crisis in recent years. Fog harvesting is identified as one of the most sustainable means of freshwater collection. Wettability-patterned surfaces are recognized to have a great potential for fog harvesting. In this work, patterned superhydrophobic/superhydrophilic surface has been fabricated directly on aluminum alloy AA6061 via a nanosecond laser texturing. The superhydrophobic region contains low-roughness, isotropic, random nanostructures whereas the superhydrophilic regions contains highly structured porous microchannels. The fabricated AA6061 surface demonstrated ∼72% enhanced fog harvesting capability compared to the untreated one. Moreover, unlike other fabrication processes, the whole process has more flexibility to create innovative patterns without any requirement of mask.