Chemical and UV durability of hydrophobic and icephobic surface layers on femtosecond laser structured stainless steel

Abstract

Femtosecond-laser processing significantly alters the surface's structure and chemical composi-tion, impacting its wetting properties. Post-treatments such as immersion in a hydrocarbon liq-uid (petrol) or storage in a vacuum can significantly reduce ice adhesion, making the surfaces interesting for anti-ice applications. This study investigates their durability against acetone, eth-ylene-glycol as well as against UV radiation. The laser-structured surfaces were immersed in the respective liquids for up to 48 hours. The results indicate limited durability of the superhydro-phobic and icephobic layers when submerged in acetone and ethylene-glycol, with more favor-able results for petrol treatment than vacuum treatment. Similar results were obtained after 100 hours of UV exposure, showing a decrease in superhydrophobic properties and an increase in ice adhesion; however, a repeated vacuum treatment conducted after the chemical durability tests revealed the potential for a partial recovery of the hydrophobic and icephobic properties. XPS analysis was performed throughout the experiments to evaluate changes in surface chemistry resulting from the post-laser treatments and the durability tests.