Recent advances in the mechanical durability of superhydrophobic materials

This review provides an overview of recent advances in the application of superhydrophobic surfaces to act as corrosion barriers. The adverse consequences of corrosion are a serious and widespread problem resulting in industrial plant shutdowns, waste of valuable resources, reduction in efficiency, loss or contamination of products, and damage to the environment. Superhydrophobic surfaces, inspired by nature, can be considered as an alternative means for improving the protection of metals against corrosion. Due to the possibility of minimizing the contact area between liquids and a surface, superhydrophobic surfaces can offer great resistance to corrosion. Artificial superhydrophobic surfaces have been developed with the potential of being applied in numerous settings including self-cleaning, anti-icing, oil-water separation, and especially anti-corrosion applications. In this paper, we review the concept of superhydrophobicity through presentation of different theoretical models. The fabrication and application of superhydrophobic surfaces are presented, and we then discuss the use of superhydrophobic coatings as barriers against the corrosion of metals.

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Application of superhydrophobic coatings as a corrosion barrier : a review

https://profdoc.um.ac.ir/articles/a/1087371.pdf

Science and Engineering of Superhydrophobic Surfaces: Review of Corrosion Resistance, Chemical and Mechanical Stability

Icephobic materials: Fundamentals, performance evaluation, and applications

https://ddd.uab.cat/pub/artpub/2019/214190/desstrsha_a2019v138p68.pdf

Design Strategies for Shape-Controlled Magnetic Iron Oxide Nanoparticles

A simple one-step process was developed to fabricate a superhydrophobic surface on copper alloy substrates, which was applied by immersing the sheets in a solution containing sodium hydroxide (NaOH), ammonium persulphate ((NH4)2S2O8) and fluoroalkyl-silane (FAS-17) molecules. The consequent surface was characterized by contact angle measurements, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The water contact angle (CA) and sliding angle (SA) on the resulting surface were ∼158° and ∼4°, respectively. Here, the stability of the obtained surfaces was measured by a wearing test. The damaged coatings can be quickly repaired by a one-step solution-immersion process. Subsequently, the liquid/solid friction on the distinct wetting surface was studied by using a water spraying system. By comparing the friction on a normal surface and the as-prepared surface at different flow velocities, we found that superhydrophobic coatings exhibited an excellent drag reduction of ∼40% at a low wall shear rate and ∼20% at high wall shear rate. Based on these results, we attribute the superhydrophobic drag-reducing results to the plastron effect, which is characterized by surface wetting and roughness. This study not only presented a simple one-step method to fabricate a superhydrophobic surface on the copper alloy substrates but also showed the drag-reducing effect on the obtained surfaces for engineering applications.

Superhydrophobic surfaces created by a one-step solution-immersion process and their drag-reduction effect on water

Facile and fast fabrication method for mechanically robust superhydrophobic surface on aluminum foil

The present invention relates to a preparation method for a superamphiphobic surface of aluminum and an alloy thereof. According to the present invention, a two-step method is adopted to prepare a superhydrophobic surface, and a low surface energy material is adopted to modify the hydrophobic surface, wherein an electrochemical etching method is adopted to prepare an aluminum micron-scale rough surface, then a hydrothermal synthesis method is adopted to synthesize a zinc oxide micro-nano double rough structure, and the prepared superhydrophobic surface provides a contact angle of more than 156 DEG for water, and provides an oleophobic angle of more than 150 DEG C for lubricating oil; and the method has the following characteristics that: simpleness and practicality are provided, equipment requirements are low, the used electrochemical etching technology and the used hydrothermal synthesis technology are mature, the large-area superamphiphobic surface is easily prepared, and industrial manufacturing is easily achieved.

Preparation method for superamphiphobic surface of aluminum and alloy thereof

The invention relates to a preparation method of aluminum or aluminum alloy super-hydrophobic surface. The method comprises the followings: using ethanol and deionized water sequentially to ultrasonically cleaning an aluminum or an aluminum alloy piece; taking oxalic acid aqueous solution as electrolyte, an aluminum or aluminum alloy piece as an anode, and graphite as a cathode, carrying out oxidation in electrifying and water bathing, constructing a pyramidal surface with a micro-nano composite structure in one step, then cleaning the aluminum or aluminum alloy piece again, and drying; and decorating the aluminum or aluminum alloy piece after anode oxidation by adopting a low surface energy material, and then drying, namely the super-hydrophobic surface is obtained. By adopting the anode oxidation technology, a duality composite structure with a pyramidal micron structure and a nanowire can be constructed under high current in one step, the method used is simple and convenient, the technology is mature, and the preparation time is reduced greatly; and temperature requirements for anode oxidation are very low, and the preparation can be performed under low temperature and constant-temperature conditions. The contact angle of the prepared super-hydrophobic surface to water can reach more than 155 degrees.

Preparation method of aluminum or aluminum alloy super-hydrophobic surface

The resistance of the bearing is a significant factor affecting the performance of the ball-disk rotor gyroscope. The micro and nano combined surface with low surface energy material modifications can be hydrophobic. This can reduce the drag when the bearing is lubricated by deionized water. Laser ablation method is utilized to form micron-scaled structures on the surface of the stainless steel rotor ball. And the nanostructures are formed by PEI (Polyetherimide) regulated ZnO nanowires growth. After low surface energy material modification, the water contact angle of processed surface was 163° and the sliding angle was less than 4°. The maximum rotational speed was enhanced by up to 82.77% at 1.5 W driving power. Experiments show that the superhydrophobic drag-reduction spherical bearing has good short-term reliability. At 5 V drive voltage, the bearing can extend the rotational speed of ball-disk rotor gyroscope to 35000 rpm, and maintain the normal operation for longer than 40 minutes. This is quite meaningful for short-term-work or one-time-use rotor gyroscopes.

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Yang Wang

Papers

Superhydrophobic surfaces created by a one-step solution-immersion process and their drag-reduction effect on water

Facile and fast fabrication method for mechanically robust superhydrophobic surface on aluminum foil

Preparation method for superamphiphobic surface of aluminum and alloy thereof

Preparation method of aluminum or aluminum alloy super-hydrophobic surface

Superhydrophobic Drag-Reduction Spherical Bearing Fabricated by Laser Ablation and PEI Regulated ZnO Nanowire Growth