Progress in Non-Traditional Processing for Fabricating Superhydrophobic Surfaces

Abstract

When the water droplets are on some superhydrophobic surfaces, the surface only needs to be inclined at a very small angle to make the water droplets roll off. Hence, building a superhydrophobic surface on the material substrate, especially the metal substrate, can effectively alleviate the problems of its inability to resist corrosion and easy icing during use, and it can also give it special functions such as self-cleaning, lubrication, and drag reduction. Therefore, this study reviews and summarizes the development trends in the fabrication of superhydrophobic surface materials by non-traditional processing techniques. First, the principle of the superhydrophobic surfaces fabricated by laser beam machining (LBM) is introduced, and the machining performances of the LBM process, such as femtosecond laser, picosecond laser, and nanosecond laser, for fabricating the surfaces are compared and summarized. Second, the principle and the machining performances of the electrical discharge machining (EDM), for fabricating the superhydrophobic surfaces, are reviewed and compared, respectively. Third, the machining performances to fabricate the superhydrophobic surfaces by the electrochemical machining (ECM), including electrochemical oxidation process and electrochemical reduction process, are reviewed and grouped by materials fabricated. Lastly, other non-traditional machining processes for fabricating superhydrophobic surfaces, such as ultrasonic machining (USM), water jet machining (WJM), and plasma spraying machining (PSM), are compared and summarized. Moreover, the advantage and disadvantage of the above mentioned non-traditional machining processes are discussed. Thereafter, the prospect of non-traditional machining for fabricating the desired superhydrophobic surfaces is proposed.

Advances in the Fabrication and Characterization of Superhydrophobic Surfaces Inspired by the Lotus Leaf

“…Different process parameters including scanning distance, laser fluence, pulse repetition rate influence the size and quality of the resulting structures [ 112 , 115 , 120 , 121 , 122 ]. Lu et al [ 123 ] investigated the effect of laser fluence (2.69–9.55 J/cm 2 ) on fabricating different sizes of micro-cracks and microstructures on 316L SS substrates by UV nanosecond laser texturing.…”

“…On the other hand, shorter pulse lasers such as femtosecond lasers provide higher precision and minimal thermal effects around the ablation spot. The main disadvantage of shorter lasers is that they tend to be more expensive [ 120 , 121 , 126 , 127 ]. Khan et al [ 121 ] investigated the wettability and self-cleaning performance of three laser ablated metals (aluminum, copper and galvanized steel) with femtosecond and picosecond pulse durations with different scanning speeds, followed by storage in air and in a low-pressure environment.…”

Biology and nature: Bionic superhydrophobic surface and principle

“…After that, Wensel and Cassie summarized Wensel model ( Wenzel, 1949 ) and Cassie–Baxter model ( Cassie, 1948 ) by studying the relationship between surface roughness and wettability, and pointed out that superhydrophobicity increased with the decrease of surface free energy and the increase of surface roughness. In modern times, more models have been optimized and pointed out ( Miljkovic et al, 2013 ; Jiang et al, 2020 ; Mohseni et al, 2021 ; Shen et al, 2021 ).…”

Facile Manufacture of Oxide-Free Cu Particles Coated with Oleic Acid by Electrical Discharge Machining

“…This phenomenon is illustrated schematically in Figure 1. The continual dielectric fluid flow aids in the maintenance of a neat inter-electrode gap, and contaminants from the machining region are washed away [9]. Equipment for sports, biomedical, pharmaceutical, and motorised investigation are utilised from Electrical Discharge Machining (EDM).…”