Superhydrophobic microspiked surface structures by ultrashort laser patterning

ABSTRACT

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/cm² showed superhydrophobic character with a high contact angle about 158 ± 3° and low contact angle hysteresis <5°.

KEYWORDS:

• Ultrafast laser
• superhydrophobic
• nanoscale
• steel
• picosecond and micro-cones

Acknowledgements

This work was co-financed by the European Regional Development Fund and the state budget of the Czech Republic (project HiLASE CoE: grant number CZ.02.1.01/0.0/0.0/15_006/0000674) and the Ministry of Education, Youth and Sports of the Czech Republic (Programme NPU I Project No. LO1602).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was co-financed by the European Regional Development Fund and the state budget of the Czech Republic (project HiLASE CoE: grant number CZ.02.1.01/0.0/0.0/15_006/0000674) and the Ministry of Education, Youth and Sports of the Czech Republic (Programme NPU I Project No. LO1602).