Fabrication of Superhydrophobic Surface with Curved Grooves Using High Power Diode Laser.

Most studies on hydrophobic surfaces processed by lasers rely on the use of pico- or femtosecond lasers. However, in industrial application, the fabrication methods using pico- or femtosecond lasers have the disadvantages of high cost and low efficiency In this study, we tried to fabricate hydrophobic surfaces using a high-power general-purpose diode laser. We have fabricated various micro/nano hierarchical structures for aluminum (Al5052) surface using laser groove processing technology. The surface of laser ablated micro structure is decorated with nano roughness, resulting in micro/nano hierarchical structure. Specimen with curved grooves are fabricated, and the correlation of wettability characteristics with spaces, widths, and curvature radii of grooves are presented. It was found that the higher contact angle was formed with a decrease of the curvature radius. We have also fabricated specimens with various micro-wavy surface pattern. The water droplets on the micro-wavy pattern kept the spherical shape with a high contact angle of 165 degrees or more.