Superhydrophobic microspiked surface structures by ultrashort laser patterning

In this study, self-organised microspiked surface structures were fabricated with a picosecond laser source on austenite stainless steel. The laser-processed surface structures were subjected to low-temperature annealing for chemical modification to reduce the surface free energy of the metal oxides formed due to laser processing. The low-temperature treatment accelerates the adsorption of organic contamination, leading to the formation of ultralow water adhesion surface in few hours compared to the prolonged ageing process. The effect of the number of pulses/spot (PPS) and fluence with respect to the geometrical shape and its impact on wetting behaviour has been systematically investigated. The density of the nanoscale protrusions and the overlay of spongy porous nanoscale structures were influenced by the number of PPS and applied energy density. The multi-scale structures generated with a fluence of 1.3 J/cm(2) showed superhydrophobic character with a high contact angle about 158 +/- 3 degrees and low contact angle hysteresis <5 degrees.

Automated summary

It was found in the study that self-organised microspiked surface structures fabricated with a picosecond laser source on austenite stainless steel can reduce the surface free energy of metal oxides and achieve ultralow water adhesion surfaces after low-temperature treatment. The density and structure of nanoscale protrusions can be controlled by adjusting the number of pulses/spots and fluence, leading to superhydrophobic surfaces with high contact angles and low contact angle hysteresis.