Special Issue "Water and Oil Repellent Surfaces"

A special issue of Coatings (ISSN 2079-6412).

Deadline for manuscript submissions: closed (30 July 2020).

Special Issue Editor

Prof. Dr. Ioannis Karapanagiotis
Website
Guest Editor
University Ecclesiastical Academy of Thessaloniki, N. Plastira 65, 542 50 Thessaloniki, Greece
Interests: coatings; surfaces & interfaces; wetting & dewetting; superhydrophobicity & superomniphobicity; water-repellency & self-cleaning; nanostructured materials; biomimetics; nanocomposites; nanoparticles; polymers; archaeological chemistry; conservation science
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Special Issue Information

Dear Colleagues,

In the last two decades, materials of extreme wetting properties (MEWP) have received significant attention, as they offer new perspectives providing numerous potential applications. Biomimetics, super-hydrophobic/oleophobic and water-/oil-repellent surfaces can be used, for instance, in automobiles; ships and aircrafts; microelectronics; textiles; biomedical devices and implants; devices in renewable energy systems; constructions and buildings; and in other applications relevant to self–cleaning, friction reduction, oil–water separation, water harvesting and desalination, drug delivery, anti-icing, anti-corrosion, and anti-bacteria methods.

Despite the large scientific progress on MEWP, there are still some obstacles that have to be solved to make these materials available for real life applications. For example, the durability of the surfaces of MEWP is clearly a main obstacle. Recent advances on the production strategies, including methods and materials, of MEWP showed that the durability and sustainability obstacles can be addressed. Recent studies suggest that metals, semiconductors, ceramics, polymers (natural and synthetic), and modern materials such as nanocomposites and graphene can be tuned to MEWP following cost-effective and eco-friendly methods and materials.

 The scope of this Special Issue will serve as a forum for papers on the following concepts:

  • Robust water/oil repellent surfaces;
  • Transparent water/oil repellent surfaces;
  • Self-recovery water/oil repellent surfaces;
  • Waterborne coatings with extreme wetting propeties;
  • Anti-icing surfaces;
  • Antibacterial surfaces of extreme wetting properties;
  • Antigraffiti surfaces of extreme wetting properties;
  • Blood-repellent surfaces ;
  • Engineered wettability for water harvesting;
  • Superhydrophilic-superhydrophobic micropatterns;
  • Water-repellent cellulose surfaces (fabrics, paper);
  • Water-repellent coatings for electronics;
  • Water-repellent coatings for automobiles, aircrafts, and ships;
  • Water-repellent wood surfaces;
  • Water-repellent metal surfaces;
  • Water-repellent coatings for building protection;
  • Graphene: from superhydrophilic to superhydrophobic surfaces.

 Prof. Dr. Ioannis Karapanagiotis

Guest Editor

Keywords

  • Superhydrophobic surfaces and coatings;
  • Water-repellent surfaces and coatings;
  • Superoleophobic surfaces and coatings;
  • Oil repellent surfaces and coatings.

Published Papers (7 papers)

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Editorial

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Open AccessEditorial
Water- and Oil-Repellent Surfaces
Coatings 2020, 10(10), 920; https://doi.org/10.3390/coatings10100920 - 25 Sep 2020
Abstract
In the last two decades, materials of extreme wetting properties have received significant attention, as they offer new perspectives providing numerous potential applications [...] Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)

Research

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Open AccessArticle
Artificial Superhydrophobic and Antifungal Surface on Goose Down by Cold Plasma Treatment
Coatings 2020, 10(9), 904; https://doi.org/10.3390/coatings10090904 - 20 Sep 2020
Abstract
Plasma treatment, especially cold plasma generated under low pressure, is currently the subject of many studies. An important area using this technique is the deposition of thin layers (films) on the surfaces of different types of materials, e.g., textiles, polymers, metals. In this [...] Read more.
Plasma treatment, especially cold plasma generated under low pressure, is currently the subject of many studies. An important area using this technique is the deposition of thin layers (films) on the surfaces of different types of materials, e.g., textiles, polymers, metals. In this study, the goose down was coated with a thin layer, in a two-step plasma modification process, to create an artificial superhydrophobic surface similar to that observed on lotus leaves. This layer also exhibited antifungal properties. Two types of precursors for plasma enhanced chemical vapor deposition (PECVD) were applied: hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDSN). The changes in the contact angle, surface morphology, chemical structure, and composition in terms of the applied precursors and modification conditions were investigated based on goniometry (CA), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). The microbiological analyses were also performed using various fungal strains. The obtained results showed that the surface of the goose down became superhydrophobic after the plasma process, with contact angles as high as 161° ± 2°, and revealed a very high resistance to fungi. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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Open AccessArticle
Effect on Silt Capillary Water Absorption upon Addition of Sodium Methyl Silicate (SMS) and Microscopic Mechanism Analysis
Coatings 2020, 10(8), 724; https://doi.org/10.3390/coatings10080724 - 24 Jul 2020
Abstract
Silt has the characteristics of developed capillary pores and strong water sensitivity, and capillary water is an important factor inducing the erosion and slumping of silt sites. Therefore, in order to suppress the effect of capillary water, this article discusses the improvement effect [...] Read more.
Silt has the characteristics of developed capillary pores and strong water sensitivity, and capillary water is an important factor inducing the erosion and slumping of silt sites. Therefore, in order to suppress the effect of capillary water, this article discusses the improvement effect of sodium methyl silicate (SMS) on silt. The effect was investigated by capillary water rise testing and contact angle measurement, and the inhibition mechanism is discussed from the microscopic view by X-ray diffraction (XRD) testing, X-ray fluorescence (XRF) testing, scanning electron microscope (SEM) testing and mercury intrusion porosimetry (MIP) testing. The results show that SMS can effectively inhibit the rise of capillary water in silt, the maximum height of capillary rise can be reduced to 0 cm when the ratio of SMS (g) to silt (g) increases to 0.5%, and its contact angle is 120.2°. In addition, considering also the XRD, XRF, SEM and MIP test results, it is considered that SMS forms a water-repellent membrane by reacting with water and carbon dioxide, which evenly distribute on the surface of silt particles. The membrane reduces the surface energy and enhances the water repellence of silt, and combines with small particles in the soil, reduces the number of 2.5 μm pores and inhibits the rise of capillary water. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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Open AccessCommunication
Superhydrophobic Coatings Based on Siloxane Resin and Calcium Hydroxide Nanoparticles for Marble Protection
Coatings 2020, 10(4), 334; https://doi.org/10.3390/coatings10040334 - 01 Apr 2020
Cited by 1
Abstract
Calcium hydroxide (Ca(OH2)) nanoparticles are produced following an easy, ion exchange process. The produced nanoparticles are characterized using transmission electron microscopy (TEM) and Fourier- transform infrared spectroscopy (FTIR) and are then dispersed in an aqueous emulsion of silanes/siloxanes. The dispersions are [...] Read more.
Calcium hydroxide (Ca(OH2)) nanoparticles are produced following an easy, ion exchange process. The produced nanoparticles are characterized using transmission electron microscopy (TEM) and Fourier- transform infrared spectroscopy (FTIR) and are then dispersed in an aqueous emulsion of silanes/siloxanes. The dispersions are sprayed on marble and the surface structures of the deposited coatings are revealed using scanning electron microscopy (SEM). By adjusting the nanoparticle concentration, the coated marble obtains superhydrophobic and water repellent properties, as evidenced by the high static contact angles of water drops (> 150°) and the low sliding angles (< 10°). Because Ca(OH)2 is chemically compatible with limestone-like rocks, which are the most common stones found in buildings and objects of the cultural heritage, the produced composite coatings have the potential to be used for conservation purposes. For comparison, the wetting properties of another superhydrophobic and water repellent coating composed of the same siloxane material and silica (SiO2) nanoparticles, which were commonly used in several previously published reports, were investigated. The suggested siloxane+Ca(OH)2 composite coating offers good protection against water penetration by capillarity and has a small effect on the aesthetic appearance of marble, according to colorimetric measurements. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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Open AccessFeature PaperArticle
Anti-Graffiti Behavior of Oleo/Hydrophobic Nano-Filled Coatings Applied on Natural Stone Materials
Coatings 2019, 9(11), 740; https://doi.org/10.3390/coatings9110740 - 07 Nov 2019
Cited by 2
Abstract
In recent years, graffiti writings are increasingly regarded as a form of art. However, their presence on historic building remains a vandalism and different strategies have been developed to clean or, preferably, protect the surfaces. In this study, an experimental nano-filled coating, based [...] Read more.
In recent years, graffiti writings are increasingly regarded as a form of art. However, their presence on historic building remains a vandalism and different strategies have been developed to clean or, preferably, protect the surfaces. In this study, an experimental nano-filled coating, based on fluorine resin containing SiO2 nano-particles, and two commercial products have been applied on compact and porous calcareous stones, representative of building materials used in the Mediterranean basin, and their anti-graffiti ability has been analyzed. All the tested experimental and commercial coatings exhibited high hydrophobicity and oleophobicity, thus meeting one of the basic requirements for anti-graffiti systems. The effects of staining by acrylic blu-colored spray paint and felt-tip marker were, then, assessed; the properties of the treated stone surfaces after cleaning by acetone were also investigated. Visual observations, contact angle measurements and color evaluations were performed to this aim. It was found that the protective coatings facilitated the spray paint removal; however high oleophobicity or paint repellence did not guarantee a complete cleaning. The stain from the felt-tip marker was confirmed to be extremely difficult to remove. The cleaning with a neat unconfined solvent promoted the movement of the applied polymers (and likely of the paint, as well) in the porous structure of the stone substrate. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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Open AccessArticle
A Facile Route to Fabricate Superhydrophobic Cu2O Surface for Efficient Oil–Water Separation
Coatings 2019, 9(10), 659; https://doi.org/10.3390/coatings9100659 - 12 Oct 2019
Cited by 2
Abstract
The mixture of insoluble organics and water seriously affects human health and environmental safety. Therefore, it is important to develop an efficient material to remove oil from water. In this work, we report a superhydrophobic Cu2O mesh that can effectively separate [...] Read more.
The mixture of insoluble organics and water seriously affects human health and environmental safety. Therefore, it is important to develop an efficient material to remove oil from water. In this work, we report a superhydrophobic Cu2O mesh that can effectively separate oil and water. The superhydrophobic Cu2O surface was fabricated by a facile chemical reaction between copper mesh and hydrogen peroxide solution without any low surface reagents treatment. With the advantages of simple operation, short reaction time, and low cost, the as-synthesized superhydrophobic Cu2O mesh has excellent oil–water selectivity for many insoluble organic solvents. In addition, it could be reused for oil–water separation with a high separation ability of above 95%, which demonstrated excellent durability and reusability. We expect that this fabrication technique will have great application prospects in the application of oil–water separation. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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Open AccessArticle
Assembly Mechanism and the Morphological Analysis of the Robust Superhydrophobic Surface
Coatings 2019, 9(8), 472; https://doi.org/10.3390/coatings9080472 - 26 Jul 2019
Cited by 1
Abstract
Robust superhydrophobic surfaces are fabricated on different substrates by a scalable spray coating process. The developed superhydrophobic surface consists of thin layers of surface functionalized silica nanoparticle (SiO2) bound to the substrate by acrylate-polyurethane (PU) binder. The influence of the SiO [...] Read more.
Robust superhydrophobic surfaces are fabricated on different substrates by a scalable spray coating process. The developed superhydrophobic surface consists of thin layers of surface functionalized silica nanoparticle (SiO2) bound to the substrate by acrylate-polyurethane (PU) binder. The influence of the SiO2/PU ratio on the superhydrophobicity, and the robustness of the developed surface, is systematically analyzed. The optimized SiO2/PU ratio for prepared superhydrophobic surfaces is obtained between 0.9 and 1.2. The mechanism which yields superhydrophobicity to the surface is deduced for the first time with the help of scanning electron microscopy and profilometer. The effect of mechanical abrasion on the surface roughness and superhydrophobicity are analyzed by using profilometer and contact angle measurement, respectively. Finally, it is concluded that the binder plays a key role in controlling the surface roughness and superhydrophobicity through the capillary mechanism. Additionally, the reason for the reduction in performance is also discussed with respect to the morphology variation. Full article
(This article belongs to the Special Issue Water and Oil Repellent Surfaces)
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