Femtosecond laser processing of superhydrophobic microstructures on the surface of AH36 steel plate

Superhydrophobic surfaces are the most commonly used functional surfaces. Femtosecond laser processing technology has emerged as a useful instrument for producing micro- and nanoscale structures on superhydrophobic surfaces because of its extremely high processing accuracy and highly controlled features. The substrate materials used in this work are AH36 steel plates. By varying the laser processing parameters, the microstructure shapes of steel plate surface are produced. After processing, the samples were allowed to rest in air for 30 days before characterizing their hydrophobicity. The optical and scanning electron microscopy were used to analyze its morphology, and the contact angles were measured. The study demonstrated that the surface roughness, microstructure, and hydrophobicity of AH36 steel plate samples vary with laser parameters. As a result, the AH36 steel plate exhibits the creation of a superhydrophobic surface when the contact angle reaches 151.2°, with a scanning interval of 100 μm between two lines, scanning speed of 10 mm/s, and an energy density of 3.67 J/cm². This is an important result for promoting femtosecond laser in preparing hydrophobic structures on marine metal surface.