Bioinspired superhydrophobic surface via one-step electrodeposition and its corrosion inhibition for Mg-Li alloy

Icing behavior of supercooled droplets on superhydrophobic polymercoatings between lotus effect and petal effect

This paper investigated anti-icing behavior and wettability of droplets on superhydrophobic polymercoatings between lotus effect and petal effect, which were prepared on surfaces of 2021 aluminum alloy with 1H, 1H, 2H, 2H-heptafluorodecyl (FAS-17). The prepared surfaces displayed excellent hydrophobicity with contact angles of 154.9° ± 1.5°and 139.8° ± 1.3°, while rolling angles are 4° ± 1.0° (lotus effect) and 30° ± 1.5° (petal effect). Thus, the present study focused on the different characterizations and the anti-icing potential of the superhydrophobic polymersurfaces were analyzed based on three parameters including the icing delay time, the crystallization temperature of water droplets, and contact time of impinging droplets on the cold superhydrophobic polymer coatings (−15 °C). Furthermore, the anti-icing of superhydrophobic coatings between lotus effect and petal effect with freezing time and crystallization temperature experimental phenomena were consistent with the thermodynamic analysis. It is also proved that the droplets have different bounce behavior on different polymercoating surfaces by droplet impact experiment. The study offers a comprehensive perspective on polymercoatings of different wetttablility for anti-icing behavior applications.

Flower-like Superhydrophobic Surfaces Fabricated on Stainless Steel as a Barrier against Corrosion in Simulated Acid Rain

Functionalisation of the metal surface of low-carbon ferritic stainless steel (from hydrophilic to hydrophobic properties) was achieved by flower-like hierarchical structures on a steel substrate prepared by a low-cost immersion method. The flower-like structured hydrophobic layers on the steel substrate were obtained by immersing the samples in an ethanolic solution of stearic acid with the addition of various concentrations of expired vitamin E ((+)α-tocopherol). The stability and corrosion-inhibiting effect of the hierarchically structured (such as natural cornflower) hydrophobic layers were studied systematically during short and long immersion tests, 120 h (five days) in an acidic environment (pH = 3) using potentiodynamic measurements, electrochemical impedance spectroscopy and chronopotentiometry. The surfaces of the samples, their wettability, surface morphology and chemical composition were characterised by contact angle measurements, SEM, ATR-FTIR and EDAX. After 120 h of immersion, the inhibition efficiency of the flower-like structured hydrophobic layers on the steel substrate in the selected corrosion medium remained above 99%, and the hierarchical structure (flower-like structure) was also retained on the surface.