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Herein, on a zinc substrate, a superhydrophobic Co5Zn21 alloy surface with a nanometer needle structure was fabricated by immersing processed Zn sheets perpendicularly into a cobalt(ii) nitrate aqueous solution followed by the annealing treatment. This alloy surface exhibited not only outstanding superhydrophobicity with a water contact angle of 160° but also excellent mechanical durability and corrosion resistance. The morphology and chemical composition of the superhydrophobic surface (SHS) were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction pattern (XRD), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the samples was characterized via polarization, Nyquist, and bode modulus plots. The SHS endures mechanical stretch for more than 800 mm of abrasion using sandpaper with different grit sizes (P1200, P800, and P400) and shows abrasion resistance. When the superhydrophobic surface lost its superhydrophobicity after a long-term damage, the superhydrophobicity could be easily regenerated again by immersion and annealing treatment. The surface after repair can still maintain its superhydrophobicity after anti-friction, anti-ice, and UV irradiation tests. [ABSTRACT FROM AUTHOR]

A stable Ni-AlNi-AlO superhydrophobic surface (SHS) was fabricated on aluminum (Al) substrate via etching, subsequent replacement deposition and then annealing. The water contact angle of the SHS could reach to 155°, and the water sliding angle was less than 2°. The morphology and chemical composition of the samples were characterized using scanning electron microscopy, X-ray diffraction pattern, energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. Anti-corrosion behaviors of the samples were investigated via Tafel extrapolation and electrochemical impedance, and the SHS showed a better corrosion resistance than that of pure Al. In addition, when the water drops impinged on the SHS, the drops could fully bounce, exhibiting exquisite self-cleaning property. The catalytic property of the samples was evaluated by the reduction of 4-nitrophenol (4-NP) at room temperature, in which the SHS served as the hydrogen generator as well as a catalyst. The degradation rate of 4-NP at the existence of the superhydrophobic samples in NaOH aqueous solution was 97%. And the reaction rate constant of 4-NP at the existence of the superhydrophobic samples was 9.51 × 10 s, which was about twice as large as that at the existence of pure Al. This work offers an effective strategy to fabricate SHSs and expands industrial applications for Al and its alloys. [ABSTRACT FROM AUTHOR]

The paper reports on the preparation of NiO/ZnO superhydrophobic surfaces (SHS) on zinc via chemical substitution/deposition and thermal annealing. The resulting surfaces display superhydrophobic behavior with a water contact angle (WCA) of 153° and a sliding angle (SA) of ∼5° without the use of any additional organic coating. Using the Cassie-Baxter equation, it is found that about 91.6% serves as the contact area of the water droplet and air, leading to the roll down property of the water droplet on the surface. The surface superhydrophobicity is controlled and influenced by various preparation conditions: the thermal treatment, which causes the generation of NiO and ZnO layers, and the formation of polygonal honeycomb structures and disappearance of silk flower-like clusters. The resulting NiO/ZnO SHS exhibit roll down, anti-corrosion and anti-abrasion properties. The corrosion current density of the NiO/ZnO SHS (5.7 × 10 −4 A cm −2 ) is decreased by more than 1 order of magnitude when compared to the untreated Zn surface (1.4 × 10 −3 A cm −2 ). EIS results also indicate that the SHS possesses higher anti-corrosion performance. The superhydrophobic sample, after annealing treatment, can sustain a collapsing force of about 7.8 N, which is better than the superhydrophilic sample without annealing treatment (∼5.2 N). This controlled fabrication process may offer new avenues for designing superhydrophobic surfaces with corrosion resistance for more practical applications. [ABSTRACT FROM AUTHOR]

Herein, Cu–CuO–Fe2O3/Fe superhydrophobic surfaces (SHSs) were successfully fabricated on an iron substrate via chemical substitution deposition and subsequent annealing treatment. The resulting surfaces exhibit remarkable superhydrophobicity with a water CA of 165 ± 2° and an SA of approximately 0° without any organic modification. The surface morphology and chemical compositions were investigated using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS); moreover, the surface roughness was analyzed via atomic force microscopy (AFM). The thermal treatment, which caused generation of a new chemical substance and formation of micro-/nano-binary architectures, was important for superhydrophobicity and also enhanced the affinity of the iron substrate for the coatings. The annealing temperature and time were further investigated to explain the significance of the surface morphology and chemical composition in the fabrication of the optimal SH samples under appropriate conditions. The resulting SHSs exhibit roll-down, anti-abrasion, and anti-corrosion properties, which may have significant potential value for more applications. [ABSTRACT FROM AUTHOR]

In this work, a facile approach was developed for producing stable Ag–Fe2O3/Fe superhydrophobic surfaces (SHSs) with dendritic structures. The hierarchical structures were fabricated on iron substrates through etching in a hydrochloric acid aqueous solution and a simple replacement deposition process was carried out without any organic modification, followed by annealing. The contact angle can reach 164 ± 1° and the sliding angle is almost 2 ± 1°. By comparison, the catalytic properties of the hydrophilic sample and SHS were examined. The SHS exhibited excellent catalytic performance. The rate constant of SHS was 3.00 × 10−3 s−1, which was about three times higher than that of the hydrophilic sample without annealing, and the degradation rate was maintained above 90% after ten recycles. The experimental results showed that the as-prepared SHSs exhibited excellent catalytic, self-cleaning, anti-corrosion, and anti-icing properties. [ABSTRACT FROM AUTHOR]