Superhydrophobic Surfaces Prepared by Microstructuring of Silicon Using a Femtosecond Laser

TLDR

Laser irradiation of silicon produces micro‑ and nanoscale surface morphology. We present a simple method for fabricating superhydrophobic silicon surfaces. The method uses femtosecond laser irradiation of silicon wafers followed by fluoroalkylsilane coating, with laser fluence adjusted to tune surface morphology and wetting, and contact angles measured for water and hexadecane. The microstructured surfaces achieve water contact angles above 160° with negligible hysteresis, while hexadecane transitions from nonwetting to wetting.

Abstract

We present a simple method for fabricating superhydrophobic silicon surfaces. The method consists of irradiating silicon wafers with femtosecond laser pulses and then coating the surfaces with a layer of fluoroalkylsilane molecules. The laser irradiation creates a surface morphology that exhibits structure on the micro- and nanoscale. By varying the laser fluence, we can tune the surface morphology and the wetting properties. We measured the static and dynamic contact angles for water and hexadecane on these surfaces. For water, the microstructured silicon surfaces yield contact angles higher than 160° and negligible hysteresis. For hexadecane, the microstructuring leads to a transition from nonwetting to wetting.