Fabrication of superhydrophobic surfaces by laser surface texturing and autoxidation

Abstract

The creation of superhydrophobic surfaces (SHS) has received exceptional thought from the entire research community due to its notable application in varied fields such as anti-icing, self-cleaning, drag reduction, anti-bacterial, and oil-water separation. The super­hy­drophobic (SH) conditions for a surface can be attained through the consolidation of a low surface energy surface with appropriate micro/nano-surface roughness through texturing. Motivated by the SH nature of lotus leaf and petal effect, microstructures have been prepared in this work on a metal surface by a fiber laser marking machine at 35 W. The textured surfaces with a different pitch to diameter (p/d) ratio (2.0-0.70) have been turned into hydrophobic and finally SH, after storing in an ambient environment for a few days due to oxide layer deposition on the textured surface. In this study, the maximum contact angle achieved by textured geometry after 30 days of auto-oxidation was 158.6 o. Further, test results showed that the fabricated surfaces have a high potential to maintain their SH nature even after the harsh condition of applications.

Owens–Wendt Method for Comparing the UV Stability of Spontaneous Liquid-Repellency with Wet Chemical Treatment of Laser-Textured Stainless Steel

“…Moreover, the stability of the layer obtained by spontaneous hydrophobization was significantly lower than that obtained by modification even with such a simple chemical substance as stearic acid. This result was also confirmed by the conclusions [79] regarding the instability of such a layer with environmental factors and, thus, casts doubt on the future practical use of such surfaces under conditions of prolonged exposure to sunlight. For outdoor applications, siloxane and possibly fluorinated modifiers are better suited, providing greater durability due to stronger interatomic bonds than hydrocarbon modifiers, such as oleic and stearic acids.…”

Influence of laser texturing on hydrophobicity and slurry erosion behaviour of VC-CuNiCr based HVOF coatings

“…Further, a 50 W fiber laser marking machine was used to create microtexturing of a circular shape with pitch of 200 μm and diameter of 50 μm. In order to create micro-texturing for superhydrophobic conditions using laser texturing, the following parameters were chosen and acquired from the literature: scanning speed of 75 mm s −1 , wavelength of 1064 nm, frequency of 75 kHz, and power of 30 W. The laser beam was repeated three times to achieve a mean surface roughness of 10 to 14 μm, which is considered as a favorable condition for superhydrophobic behaviour [30]. The pitch/diameter (p/d) ratio in laser texturing plays a very critical role and refers to the ratio between the distance between adjacent laser spots (pitch) and the diameter of the laser spot itself.…”

“…Out of the various surface processing, laser texturing is the technique that is being used these days for the development of hydrophobic surfaces [26][27][28][29]. In one of their works, Kumar et al [30], has developed superhydrophobic surfaces by laser surface texturing process. The authors further performed sandpaper abrasion test and peel-off test and attained some exceptional results.…”

Comparative study of fabricated superhydrophobic surfaces via LST with carbon soot, chemical etching and auto-oxidation

“…Thus, these droplets can be rolled off easily from the surface with a slight inclination angle. This has already been established through numerous studies that the wettability of the solid surface is determined by its surface chemistry and microscopic geometry of the surface [3][4][5]. Thus, by modifying the surface roughness and surface topography, the wettability of the solid surface can be controlled.…”