Hydrophobic and superhydrophobic surfaces fabricated using atmospheric pressure cold plasma technology: A review.

Functional surfaces for reversibly switchable wettability and oil–water separation have attracted much interest with pushing forward an immense influence on fundamental research and industrial application in recent years. This article proposed a facile method to fabricate superhydrophobic surfaces on steel substrates via electroless replacement deposition of copper sulfate (CuSO4) and UV curing of vinyl-terminated polydimethylsiloxane (PDMS). PDMS-based superhydrophobic surfaces exhibited water contact angle (WCA) close to 160° and water sliding angle (WSA) lower than 5°, preserving outstanding chemical stability that maintained superhydrophobicity immersing in different aqueous solutions with pH values from 1 to 13 for 12 h. Interestingly, the superhydrophobic surface could dramatically switch to the superhydrophilic state under UV irradiation and then gradually recover to the highly hydrophobic state with WCA at 140° after dark storage. The underlying mechanism was also investigated by scanning electron...

Polydimethylsiloxane-Based Superhydrophobic Surfaces on Steel Substrate: Fabrication, Reversibly Extreme Wettability and Oil-Water Separation.

Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

Mechanically robust and self-cleaning antireflection coatings from nanoscale binding of hydrophobic silica nanoparticles

The deposition of ice, snow, pollution or their mixtures on the surface of outdoor insulators may severely affect their performance, resulting in electrical and or mechanical failures. Various preventative methods are used to minimize the problems of ice and pollution build up on the surface of outdoor insulators. In the last few decades, advanced coatings have been developed for better performance of outdoor insulators in contaminated and freezing environments. These advanced coatings offer the advantage of low wettability, high thermal and ultraviolet resistance, self-cleaning, self-healing, low ice adhesion strength and delayed freezing time. It is believed that these benefits will not only increase the reliability of transmission systems but may also reduce the capital cost of transmission infrastructure. This paper presents a detailed review on the properties and applications of superhydrophobic coatings in outdoor high voltage insulation. This review can be beneficial to scientists and engineers in evaluating the performance and durability of superhydrophobic coatings in polluted and freezing conditions. It also highlights the need for standardized tests and procedures for better understanding the behavior of superhydrophobic coatings in different environments and their long-term durability.

Properties and applications of superhydrophobic coatings in high voltage outdoor insulation: A review

In this Letter, the dewetting behavior of superhydrophobic condensing surfaces under a tangential AC electric field is reported. The surface coverage of condensed droplets only exhibits a negligible increase with time. The jumping frequency of droplets is enhanced. The AC electric field motivates the dynamic transition of droplets from stretch to recoil, resulting in the counterforce propelling droplet jumping. The considerable horizontal component of jumping velocity facilitates droplet departure from superhydrophobic surfaces. Both the amplitude and frequency of AC voltage are important factors for droplet departure and dewetting effect. Thereby, the tangential electric field provides a unique and easily implementable approach to enhance droplet removal from superhydrophobic condensing surfaces.

Droplet condensation on superhydrophobic surfaces with enhanced dewetting under a tangential AC electric field

In this letter, we report a fast, simple, and single step approach to the preparation of transparent super-hydrophobic coatings on a copper conductor via atmosphere pressure arc discharges The preparation procedures, hydrophobic characteristics, anti-pollution capability, and transparency of the super-hydrophobic coating are presented A dual micro- and nano-scale hierarchical structure is observed on the super-hydrophobic coating with a water contact angle greater than 150° The coating is, thus, capable of removing a significant amount of contaminants with a small quantity of water droplets Attenuated total reflection Fourier transform infrared spectroscopy indicates that hydrophobic methyl groups exist on the surface of the coating The surface roughness measurement results prove that the super-hydrophobic surface obeys the Cassie-Baxter model and its light scattering is very weak Results demonstrate the conceptual feasibility of production of optically transparent super-hydrophobic coating by arc spraying of polymers under the atmospheric pressure

One-step preparation of transparent superhydrophobic coatings using atmospheric arc discharge

Super-hydrophobic coatings have recently drawn considerable attention in research and applications towards self-cleaning materials. This paper presents experiments and analysis of water droplet behaviors on glass, silicone rubber, and super-hydrophobic surface in an ac electric field applied parallel to the surface. Experimental results show that a water droplet tends to move on a super-hydrophobic surface while it tends to stretch or deform on glass and silicone rubber surfaces. A physical model of the water droplet deformation and motion mechanism is presented. An electrostatic force acting as the domain driving force plays a key role in water droplet motion on super-hydrophobic surface. The electrostatic stress acting along the external profile of a water droplet cross section was simulated using a surface integral of the Maxwell stress tensor. The simulation for surfaces with different wetting properties are in good agreement with the experimental results. Super-hydrophobic coating demonstrates a prospective electric field enhanced self-cleaning property.

Investigation of the electric field driven self-propelled motion of water droplets on a super-hydrophobic surface

In this paper, the pollution flashover performance of a superhydrophobic surface with different coating strategies are studied. The results show that a superhydrophobic coating is effective in preventing pollution flashover under high voltage. The superhydrophobic coatings show increased pollution flashover voltage when compared to room temperature vulcanized silicone rubber and to an uncoated glass substrate. A novel suppression mechanism of the superhydrophobic coating is proposed which is driven by the electrostatic force produced by the applied voltage. The coalesced slippery slurry droplets and the expanded dry area on the superhydrophobic surface contributes to increased flashover voltage on the superhydrophobic surface. The superhydrophobic coating promises to be a prospective application in anti-pollution performance of insulators.

Yuan Wei

Papers

Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

Droplet condensation on superhydrophobic surfaces with enhanced dewetting under a tangential AC electric field

One-step preparation of transparent superhydrophobic coatings using atmospheric arc discharge

Investigation of the electric field driven self-propelled motion of water droplets on a super-hydrophobic surface

Enhanced Pollution Flashover of a Slurry Coalescence Superhydrophobic Coating