CC BY
21HiLASE-O-2
Two-step nanosecond laser processing for dual-scale micro- and nanostructure fabrication of superhydrophobic stainless steel surface.
P. Hauschwitz1,2, J. Radhakrishnan1, R Bicistova1, D. Jochcova1,2, J. Brajer1, D. Rostohar1, T. Mocek1
1HiLASE Centre, Institute of Physics of the Czech Academy of Sciences, Dolni Brezany, Czech Republic
2Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic
Growing demand for superhydrophobic surfaces in recent years is associated with many attractive science and engineering applications including self-cleaning, anti-icing and anti-corrosive behaviours. Stainless steel type AISI 304L is one of the most versatile and widely used engineering material in industries. Inspired by the "lotus effect" dual scale nano/microstructures have been fabricated by direct laser writing method with nanosecond laser source using two ablation regime. Primarily, microstructures were fabricated with a tightly focused beam in strong ablation regime and subsequently in soft ablation regime to create nano-scale structures by a defocused laser beam. However, the formation of a metal oxide layer on the top of the geometries of freshly prepared laser patterned metal surface causes hydrophilic behaviour. The hydrophilic to superhydrophobic transformation takes several days or weeks by the ageing technique in atmospheric condition unless the laser-patterned surface is covered with non-polar elements with some chemical techniques. In this study, the transition time has been drastically reduced to a few hours by high vacuum processing technique by accelerating the chemisorption process. Wetting properties with respect to laser processing parameters and surface morphology are examined and found to be consistent for large droplet volumes.
