Static and Dynamic Contact Angle of Water Influenced by Femtosecond Laser Based Ripple Structures on Metals

摘要

We report on the static and dynamic contact angle on stainless steel after applying laser induced periodic surface structures and study the influence of applied femtosecond laser fluence and pulse overlap hereupon. In particular, we focus on the temporal evolution of the static contact angle, the advancing and receding contact angle, as well as on the contact angle hysteresis over a period of weeks. While directly after the generation of laser induced periodic surface structures small static contact angles and a small contact angle hysteresis are found, both properties increase after a storage of the structured specimen under ambient conditions. Particularly, the structured steel surface wetta-bility turns into a hydrophobic regime on this time scale.