Large-Scale Solution for Superhydrophobic Surfaces

2016 ◽  
pp. 247-259
Author(s):  
O. V. Myronyuk ◽  
A. V. Prydatko ◽  
V. A. Raks
Keyword(s):  
Large Scale ◽  
Superhydrophobic Surfaces

An Easy Approach for Obtaining Superhydrophobic Surfaces and their Applications

2019 ◽  
Vol 813 ◽  
pp. 37-42
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Edoardo Proverbio
Keyword(s):  
Surface Morphology ◽  
Large Scale ◽  
Adhesion Force ◽  
Industrial Applications ◽  
Contact Angles ◽  
Boiling Water ◽  
Superhydrophobic Surfaces ◽  
Acid Mixture ◽  
Short Term Treatment ◽  
Water Contact

Three different methods were used to obtain nature-inspired superhydrophobic surfaces on aluminum alloys: short-term treatment with boiling water, HF/HCl and HNO3/HCl concentrated solution etching. Afterwards a thin octadecylsilane film was deposited on all pre-treated surfaces. The surface morphology analysis showed that each method allow to obtain a specific dual nano/micro-structure. The corresponding water contact angles ranged from 160° to nearly 180°. The adhesion force between the water droplets and superhydrophobic surfaces were evaluated. The specimen etched with HF/HCl acid mixture solution showed the lowest adhesion. However, the boiling water treatment sample was characterized by the highest adhesion. Furthermore, the relationship between hydrophobic behavior and surface morphology was discussed compressively. In addition, the electrochemical measurements show that the different superhydrophobic surfaces have an excellent anti-corrosion performance evidencing promising results suitable to obtain large-scale nature-inspired superhydrophobic surfaces for several industrial applications.

Fabrication of Superhydrophobic Surfaces on Copper Substrates via Brush Plating Technique

2013 ◽  
Vol 834-836 ◽  
pp. 662-669 ◽  
Author(s):  
Ke Hu ◽  
Quan Xin Xu ◽  
Xiao Long Yang
Keyword(s):  
Large Scale ◽  
Superhydrophobic Surfaces ◽  
Scale Production ◽  
Sliding Angle ◽  
Water Contact ◽  
Copper Surfaces ◽  
Plating Technique ◽  
Large Scale Production ◽  
Sample Technique ◽  
Brush Plating

Superhydrophobic surfaces on metal substrates are often prepared via roughing the surfaces and lowering their surface energy. Composite brush plating technique is developed to prepare superhydrophobic n-SiO2/Ni brush plating composite coating on copper surfaces. Under the better process parameters, the water contact angle of the obtained superhydrophobic surface is approximately 160°, and the water sliding angle is less than 10°. The influences of plating voltage and plating time on the coating surface structure and hydrophobicity were discussed. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).The results show that the prepared surfaces have the appearance of the uniform micron papilla-like structures, which are composed of submicron globular Ni particles covered with n-SiO2nanoscale villiform structures. These hierarchical micro/nanostructures are similar to the lotus leaf and play an important role in gaining superhydrophobicity. It is expected that this sample technique will be widely used for large-scale production of superhydrophobic engineering materials.

scholarly journals A Novel Design of Hybrid Hydrophilic-Superhydrophobic Surfaces for Fog Harvesting

2021 ◽  
Vol 6 (3) ◽  
pp. 152-162
Author(s):  
Zaid Almusaied ◽  
Bahram Asiabanpour
Keyword(s):  
Water Scarcity ◽  
Large Scale ◽  
Spray Coating ◽  
Superhydrophobic Surfaces ◽  
Atmospheric Water ◽  
Continuous Growth ◽  
Collection Rate ◽  
Hydrophobic Coating ◽  
Fog Collection ◽  
Water Collection

The continuous growth in the human population and climate change exacerbates the problems related to water scarcity. Harvesting the atmospheric water can mitigate the water scarcity in many regions around the globe. Fog collection using hybrid hydrophilic-superhydrophobic surfaces has the capacity to achieve a higher water collection rate. In this paper, a new method and materials are introduced to create the hybrid surfaces. The method includes additive manufacturing- to make sheets with holes-, mixing and casting polymeric matrix composite, and a controlled spray coating mechanism. The materials comprised of hydrophobic coating on top of the acrylic printed sheet and hydrophilic composite. The ratios of the pitches to diameters of the hydrophilic regions varied during the experiments to obtain the best water generation. The water collection rate for the sample with diameters of 583 um and a pitch of 1600 um has achieved 57% more than the untreated hydrophilic sample. The contrast in wettability accomplished by this novel method has the potential to be implemented on a large scale for atmospheric water harvesting.

scholarly journals Superhydrophobic Materials With Good Oil/Water Separation And Self-Cleaning Prepared Through A Environment-Friendly And Two-Component Method

2021 ◽  
Author(s):  
Wensheng Lin ◽  
Mengting Cao ◽  
Kehinde Olonisakin ◽  
Ran Li ◽  
Xinxiang Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Substrate Surface ◽  
Superhydrophobic Surfaces ◽  
Water Separation ◽  
Environment Friendly ◽  
Two Component ◽  
Oil Water Separation ◽  
Oil Water ◽  
Self Cleaning ◽  
Coated Surfaces

Abstract A novel, versatile, environment-friendly, and economical method was developed to fabricate functional superhydrophobic surfaces on various substrates, including wood, bamboo, cotton, filter paper, sponge, glass, textile, and copper. This method involves synthesizing a two-component modifier solution consisting of SiO2 nanoparticles combination with poly(methylhydrogen)siloxane (PMHS) modification. The superhydrophobicity of the coated surfaces was created by PMHS combined with SiO2 nanoparticles to construct a rough hierarchical structure on the substrate surface. As a result, all superhydrophobic surfaces were maintained under an indoor environment and relative humidity (RH) of 50% for 30 days. Furthermore, the superhydrophobic surfaces were also maintained at environmental conditions of minus 20℃ for 24 hours. It was also confirmed that these surfaces exhibited excellent self-cleaning, oil/water separation, and elimination of underwater oil properties. The method for fabricating superhydrophobic materials proposed in this study will have great application potential in preparing large-scale superhydrophobic surfaces for use in ancient building protection.

scholarly journals A Simple and Efficient Method to Fabricate Superhydrophobic Wood with Enhanced Mechanical Durability

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 750 ◽  
Author(s):  
Han ◽  
Wang ◽  
Zhang ◽  
Pu
Keyword(s):  
Large Scale ◽  
Sio2 Nanoparticles ◽  
Contact Angles ◽  
Superhydrophobic Surfaces ◽  
High Wear Resistance ◽  
Mechanical Resistance ◽  
Water Contact ◽  
Mechanical Durability ◽  
One Step ◽  
Efficient Route

The poor durability and complex production process are two tough challenges for the practical application of superhydrophobic wood. In this work, high-mechanical-resistance superhydrophobic wood was fabricated by a one-step hydrothermal vacuum dipping method using SiO2 nanoparticles (SiO2 NPs) in combination with vinyltriethoxysilane (VTES). The as-prepared superhydrophobic surfaces exhibited water contact angles (CAs) greater than 152° and water sliding angles (SAs) less than 3°. It also exhibited robust stability and durability in harsh conditions, including finger wiping, water brushing, intense sandpaper abrasion, and severe ultrasonic cleaning. The superhydrophobic surface was created by the random distribution of oligomer-wrapped SiO2 NP spheres having different sizes. Further testing showed that the SiO2 NPs were firmly fixed on the wood substrate via chemical bonding, which contributed to the high wear resistance. The modification method developed in this work provides a simple and efficient route to fabricate large-scale, mechanically stable, and durable superhydrophobic surfaces for advanced engineering materials.

scholarly journals Evaluation of the Durability of Slippery, Liquid-Infused Porous Surfaces in Different Aggressive Environments: Influence of the Chemical-Physical Properties of Lubricants

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1170
Author(s):  
Federico Veronesi ◽  
Guia Guarini ◽  
Alessandro Corozzi ◽  
Mariarosa Raimondo
Keyword(s):  
Large Scale ◽  
Variable Viscosity ◽  
Superhydrophobic Surfaces ◽  
Harsh Environments ◽  
Systematic Evaluation ◽  
Operational Conditions ◽  
Chemical Attack ◽  
Enhanced Resistance ◽  
Porous Surfaces ◽  
Water Repellence

Liquid-repellent surfaces have been extensively investigated due to their potential application in several fields. Superhydrophobic surfaces achieve outstanding water repellence, however their limited durability in severe operational conditions hinders their large-scale application. The Slippery, Liquid-Infused Porous Surface (SLIPS) approach solves many of the durability problems shown by superhydrophobic surfaces due to the presence of an infused liquid layer. Moreover, SLIPS show enhanced repellence towards low surface tension liquids that superhydrophobic surfaces cannot repel. In this perspective, SLIPS assume significant potential for application in harsh environments; however, a systematic evaluation of their durability in different conditions is still lacking in the literature. In this work, we report the fabrication of SLIPS based on a ceramic porous layer infused with different lubricants, namely perfluoropolyethers with variable viscosity and n-hexadecane; we investigate the durability of these surfaces by monitoring the evolution of their wetting behavior after exposure to severe environmental conditions like UV irradiation, chemically aggressive solutions (acidic, alkaline, and saline), and abrasion. Chemical composition and viscosity of the infused liquids prove decisive in determining SLIPS durability; especially highly viscous infused liquids deliver enhanced resistance to abrasion stress and chemical attack, making them candidates for applicable, long-lasting liquid-repellent surfaces.

Measurement of Hydrodynamic Frictional Drag on Superhydrophobic Flat Plates in High Reynolds Number Flows

2011 ◽  
Author(s):  
Elias Aljallis ◽  
Mohammad Amin Sarshar ◽  
Raju Datla ◽  
Scott Hunter ◽  
John Simpson ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Reynolds Number ◽  
Turbulent Flow ◽  
Drag Reduction ◽  
Large Scale ◽  
Superhydrophobic Surfaces ◽  
Hydrodynamic Drag ◽  
Air Bubbles ◽  
Superhydrophobic Coating

In this paper, we report the characterization of large-scale superhydrophobic surfaces for hydrodynamic drag reduction in boundary layer flows using a high-speed towing tank system. For making superhydrophobic surfaces, flat aluminum plates (4 ft × 2 ft × 3/8 in, with sharpened leading/trailing edges) were prepared and coated with nano-structured hydrophobic particles. The static and dynamic contact angle measurements indicate that the coated surfaces correspond to a de-wetting (Cassie) state with air retained on the nano-structured surfaces. Hydrodynamic drag of the large-area superhydrophobic plates was measured to cover turbulent flows (water flow speeds up to 30 ft/s, Reynolds number in the range of 105−107) and compared with that of an uncoated bare aluminum control plate. Results show that an acceptable drag reduction was obtained up to ∼30% in the early stage of the turbulent regime which is due to reduced shear forces on the plates because of the lubricating air layer on the surface. However, in a fully developed turbulent flow regime, an increase in drag was measured which is mainly attributed to the amplified surface roughness due to the protrusions of air bubbles formed on the surface. Meanwhile, a qualitative observation suggests that the air bubbles are prone to be depleted during several runs of the high shear-rate flows, as revealed by streak lines of depleted air bubbles. This suggests that the superhydrophobic coating is unstable in maintaining the de-wetted state under dynamic flow conditions and that the increased drag results from the inherent surface roughness of the coating layer where the de-wetted state collapses to a wetted (Wenzel) state due to the depletion of air bubbles. However, it was also observed that the air bubbles would reform on the surface, with the same properties as a dry surface immersed in water, while the plate was kept statically immersed in water for 12 hours, suggesting that the superhydrophobic coating retains static stability for a de-wetted state. The experimental results illustrate that drag reduction is not solely dependent on the superhydrophobicity of a surface (e.g., contact angle and air fraction), but the morphology and stability of the surface air layer are also critical for the design and use of superhydrophobic surfaces for large-scale hydrodynamic drag reduction, especially in turbulent flow regimes.

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