Superamphiphobic Coatings Research Articles

Topography, antisoiling and anticorrosion behavior of the superamphiphobic composite coating on 5083 aluminum alloy based on microarc oxidation

Abstract The inadequate corrosion resistance of aluminum alloys significantly limits their widespread application, thereby necessitating research on enhancing their resistance to corrosion and contamination. Superamphiphobic coatings present a promising solution to mitigate this issue. In this study, spraying technology was employed in conjunction with MAO to create a superamphiphobic composite coating with exceptional corrosion resistance on the surface of 5083 aluminum alloy. The morphology, superamphiphobic characteristics, and corrosion resistance of the material were comprehensively assessed. The corrosion current density of the optimal superamphiphobic composite coating obtained via MAO followed by spraying with modified TiO2 nanoparticles (Icorr = 9.23 × 10-13 A·cm-2) was six and three orders of magnitude lower than that of 5083 aluminum alloy and the unmodified MAO coating, respectively. Furthermore, the coating exhibited a large capacitive arc diameter, enhanced charge-transfer resistance, and high |Z| value at a low frequency (0.01 Hz), signifying its excellent corrosion resistance. Additionally, the coating exhibited superamphiphobic properties with high contact angle (>150°) and low sliding angle (<10°), promoting nonwetting behavior toward various liquids with different surface tensions. This behavior can be attributed to the micro-nanostructure, which significantly enhances surface hydrophobicity and oleophobicity. Moreover, the coating demonstrated dynamic self-cleaning and antisoiling capabilities. These attributes underscored the ability of the coating to exhibit super-repellency, antisoiling performance, ultralow surface energy, and interfacial adhesion forces. Finally, the superamphiphobic composite coating demonstrated noteworthy thermal and chemical stabilities—as evaluated through heat, acid, and alkali resistance tests—thereby affirming its practical viability.

Robust and anti-corrosive superamphiphobic coatings regulated by self-levelling

Robust and anti-corrosive superamphiphobic coatings regulated by self-levelling

Dip-assembling of robust photocatalytic superamphiphobic coatings for multiple self-cleaning and anti-fouling

Superamphiphobic surface exhibits excellent self-cleaning and anti-fouling properties, which can be applied in many fields. However, the accumulation of non-volatile organic contaminates can make the superamphiphobicity invalid gradually. Herein, we proposed a novel design of superamphiphobic coating with photocatalytic ability to degrade organic contaminates, aiming for multiple self-cleaning surface. It was realized through a simple dip coating strategy with layered and self-assembled micro-nano reentrant structure assistant with low surface energy. The dip coating surface exhibits superamphiphobicity against a variety of liquids, even for hexadecane (with a low surface energy of 27.5 mN/m) also has a contact angle of 152.4° and sliding angle of 8.4°, respectively. Simultaneously, due to the photocatalytic degradation of accumulated organic contaminants that on the surface, the dip coating surface can effectively restore the superamphiphobicity cyclically with both experimental and real outdoor conditions. Besides, this novel strategy can be applied to a variety of substrates and exhibits excellent flexibility and good durability, which can resilience to over 500 times of abrasion, chemical reagent corrosion for over 48 h, endure high temperature at 300 °C for over 12 h, and over 1,000 times of bending or 500 times of torsions. Consequently, we convince that this photocatalytic superamphiphobic coating strategy brings a promising method for maintaining long-term self-cleaning and anti-fouling capabilities in variety of applications even in harsh environments.

Oil-Resistant Underoil Superhydrophilic Metallic Foams for Lampblack Prefiltration.

Superwetting/repelling coatings have been utilized to address the issue of oil contamination on lampblack prefiltration metallic foam by both academia and industry. Nevertheless, the widely adopted superamphiphobic coatings are currently costly and suffer from poor wear resistance. In this study, we propose an oil-resistant underoil superhydrophilic (LSH) coating by a dip-coating method. The subsequent heating process at 200 °C for 5 min strengthens the designed coating based on lithium polysilicate cross-linking reinforcement. The LSH coating with a minimal water contact angle up to 3.4° under soybean oil can spontaneously achieve oil desorption within 7 s under water. Moreover, the coating retains its superhydrophilicity after enduring 900 friction cycles under a 500 g load or being immersed in 50 °C soapy water for 48 h. Hence, the LSH coating with great durability on metallic foam for lampblack prefiltration resulted in a 9.3% decrease in the oil absorption weight ratio after a 17-day cooking test. This work underscores the potential application of the LSH coating in lampblack prefiltration components, presenting promising technological advancements in self-cleaning for the catering industry.

Surface engineering of Q235 carbon steel through a superamphiphobic composite coating enabling robust corrosion resistance and antifouling

Developing an efficient strategy to ensure the resistance of corrosion on Q235 carbon steel from liquid-based contaminants is a challenging work. Although superhydrophobic and superamphiphobic coatings have been fabricated, their susceptibility to oily liquids and poor mechanical robustness still limits their ability to tackle corrosion. Herein, the synthesis and fabrication of a new robust superamphiphobic nanocomposite was presented by combining the reinforcement properties of silicon oxide and the mechanical and thermal stability of zinc oxide into a polytetrafluoroethylene polymer matrix via a colloidal homogenization route. The newly developed composite exhibits a hierarchical bumpy structure, leading to excellent water and oil repellent properties. Importantly, the composite possesses a robust mechanical stability to sandpaper abrasion over a distance of 2000 cm under a 100 g load and a stronger adhesion to substrate. As a result, Q235 coated with this composite exhibits an excellent corrosion resistance in saline water for up to 120 days, and a good self-cleaning and antifouling abilities in most corrosive media. This finding reveals a new pathway for resisting the corrosion attacks on Q235 carbon steel and thereby rendering this strategy with practical application in industrial and marine settings.

Preparation of a Stable Super-Amphiphobic Coating via a Simple Sol–Gel Method

Preparation of a Stable Super-Amphiphobic Coating via a Simple Sol–Gel Method

The Preparation and Properties of a Ni-SiO2 Superamphiphobic Coating Obtained by Electrodeposition

Superamphiphobic coatings have shown great potential in many fields such as with their anti-corrosion, high-temperature resistance, self-cleaning, and drag reduction properties. However, due to the poor stability of their coatings, it is difficult to apply them on a large scale. In this paper, two kinds of SiO2 particles and nickel were co-deposited on the surface of steel to construct a micro/nano dual-scale structure by composite electrodeposition. The surface of the coating was then fluorinated with the low-surface-energy material 1H,1H,2H,2H-Perfluorodecyltriethoxysilane (AC-FAS) to prepare a Ni-SiO2 superamphiphobic coating. The coating has a water contact angle of 159° and an oil contact angle of 151°. The effect of nanoparticle concentration on the wettability and surface morphology of the coating was systematically studied. Comparative experiments revealed that the optimal micro/nanoparticle concentrations were 8 g/L of 20 nm SiO2 and 2 g/L of 1 μm SiO2. This preparation method greatly improves the corrosion resistance, wear resistance, chemical stability, and high-temperature resistance of the coating.

Robust anti-icing double-layer superamphiphobic composite coatings for heat exchangers

The formation and accumulation of ice on the heat exchangers of air conditioners significantly reduce the performance issues, as well as the stability and heating efficiency. Superhydrophobic anti-icing coatings passively achieve multifunctional anti-icing properties by minimizing water droplet contact and promoting Cassie ice formation. However, long-term performance in frigid environments remains challenge for these coatings due to limitations in anti-icing durability and mechanical properties. Herein, a double-layer polymer-SiC/F-SiO2 superamphiphobic composite coating is developed. The bottom layer comprises a polymer PAI and SiC composite, and the top layer consists of F-SiO2. The composite coating demonstrates superior performance in simultaneous frost prevention, low ice adhesion, easy frost removal, exceptional mechanical strength, and long-lasting anti-icing durability. Our developed double-layer coating exhibits low ice adhesion strength down to 9.2 kPa, remarkable mechanical resilience against scratching and flushing, and delayed frost properties. These superior anti-icing properties, manifested by both lower adhesion strength and improved frost repellency, lead to a doubling of frosting time and the easier removal of ice on coated heat exchangers compared to traditional units. The development of this novel superamphiphobic composite coating provides a practical approach to creating durable anti-icing materials, leading to significant improvements in air conditioner performance.

Rare earth oxide nanoparticles for superhydrophobic, antifouling and self-cleaning coatings

The widely used rare earth oxides (REOs) have a limited application in antifouling coatings. Here, coatings composited with REOs-1H,1H,2H,2H-perfluorodecytrimeth-oxysilane (REOs-FAS) based on hydrothermal reaction were prepared for study if REOs can be used in marine antifouling coatings. A network consisting of polydimethylsiloxane (PDMS) and REOs-FAS (REOs-FAS/PDMS) (RE = Ce, Pr, Nd) was created by using the blending method and polymerization reaction. The presence of the REOs-FAS imparts to the polymers an amphiphobic structure and disrupts the cell membrane, resulting in excellent antifouling properties and antibacterial performance. The water, coffee, and soya-bean milk droplet state on the Pr6O11-FAS/Sylgard 184 silicone elastomer with the ratio of 4:1 (PFSR-4) and the ink self-cleaning experiment demonstrated that the PFSR-4 has a perfect self-cleaning property. The most suitable surface roughness of PFSR-4 not only empowered the superhydrophobic (the contact angle of water is as high as 157° ± 2° and the sliding angle of water is as low as 5° ± 2°)-oleophobic characteristic (the contact angle of diiodomethane is as high as 132° ± 3°), but also endowed the coating with the anti-diatom (as high as 97.7 %) and anti-mussel adhesive properties. Moreover, the colored PFSR coatings were prepared to do another barrier for the adhesion of large fouling organisms, especially for the white coatings. The anti-mussel attachment ratio of purely whited PDMS was high to 84.6 %. The antibacterial REOs are appropriate for preparing multi-functional coatings. In general, the designed coating has the potential to be a durable, self-cleaning, antibacterial, and antifouling coating and could serve as a foundation for developing innovative super-amphiphobic coatings.

Superamphiphobic coating prepared via a two-step spray method: An effective coating for reducing VOCs emission from crude oil tank

In the petrochemical industry, crude oil adhesion in storage tanks leads to volatilization of volatile organic compounds (VOCs), causing environmental harm and economic losses. Superamphiphobic coatings show promise in addressing this issue, but current options face challenges like complexity, limited durability, and poor corrosion resistance. This work introduces a durable and corrosion-resistant superamphiphobic coating on Q235 carbon steel using the "paint + adhesives" two-step spray method. The first layer comprises polytetrafluoroethylene (PTFE) and epoxy resin (E-44), while the second layer consists of fluorine modified silica nanoparticles (F-SiO2). The numerous and homogeneously dispersed fluorine on the coating imparts excellent liquid-repelling properties for both water and crude oil, with a water contact angle of 164.1 ± 2.4° and a sliding angle of 1.1 ± 0.1°, as well as a crude oil contact angle of 172.1 ± 0.9° and a sliding angle of 2.5 ± 0.5°. Systematic stability tests confirm the coating's mechanical and chemical stability, suggesting its potential in practical applications. Importantly, a crude oil tank with our superamphiphobic coating can reduce non-methane hydrocarbon (NMHC) volatilization by 77.4 % ± 7.8 % compared to an uncoated tank. This research provides a superamphiphobic coating to reduce crude oil loss and VOC volatilization in petrochemical enterprises, showing significant contribution to environmental sustainability.

Multifunctional Superamphiphobic Coating Based on Fluorinated TiO2 toward Effective Anti-Corrosion.

The application of superamphiphobic coatings improves the surface's ability to repel fluids, thereby greatly enhancing its various functions, including anti-fouling, anti-corrosion, anti-icing, anti-bacterial, and self-cleaning properties. This maximizes the material's potential for industrial applications. This work utilized the agglomeration phenomenon exhibited by nano-spherical titanium dioxide (TiO2) particles to fabricate 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) modified TiO2 (TiO2@fluoroPOS) fillers with low surface energy. This was achieved through the in-situ formation of protective armor on the surface of the agglomerates using the sol-gel method and fluorination modification. Polyvinylidene fluoride-tetrafluoropropylene (PVDF-HFP) and TiO2@fluoroPOS fillers were combined using a spraying technique to prepare P/TiO2@fluoroPOS coatings with superamphiphobicity. Relying on the abundance of papillae, micropores, and other tiny spaces on the surface, the coating can capture a stable air film and reject a variety of liquids. When the coatings were immersed in solutions of 2 mol/L HCl, NaCl, and NaOH for a duration of 12 h, they retained their exceptional superamphiphobic properties. Owing to the combined influence of the armor structure and the organic binder, the coating exhibited good liquid repellency during water jetting and sandpaper abrasion tests. Furthermore, the coating has shown exceptional efficacy in terms of its ability to be anti-icing, anti-waxing, and self-cleaning.

Superamphiphobic coatings with excellent properties

Superamphiphobic coatings with excellent properties

Impalement-Resistant, Mechanically Stable, and Anti-Static Superamphiphobic Coatings Enabled by Solvent Regulation and Their Application in Anti-Icing.

Superamphiphobic coatings have good application prospects in many fields but are limited by their low impalement resistance, weak mechanical stability, and easy adhesion of tiny droplets. Here, impalement-resistant, mechanically stable, and antistatic superamphiphobic coatings were fabricated by spraying a mixture of conductive carbon black (CB), silicone-modified polyester adhesive/fluorinated SiO2 microspheres onto Al alloy. The microspheres were obtained by adhesive phase separation and the binding of fluorinated SiO2 to them. The morphology, superamphiphobicity, impalement resistance, and mechanical stability of the coatings could be regulated by using solvents with different boiling points. As a result, the coatings simultaneously exhibited outstanding mechanical stability, impalement resistance, and superamphiphobicity. The addition of conductive CB endowed the coatings with good antistatic and tiny droplet repellent properties. In addition, the coatings exhibited good anti-icing properties due to the steady air layer at the solid-liquid interface and the very small contact area between them. We suppose that the coatings are very promising for practical application in various fields, including anti-icing, due to their outstanding comprehensive properties and simple preparation process.

Hybrid superamphiphobic anti-corrosion coating with integrated functionalities of liquid repellency, self-cleaning, and anti-icing

Superhydrophobic materials have shown tremendous potential in various fields. However, the adhesion, wetting, and pinning of low-surface-tension liquids greatly limit their multifunctional applications. Therefore, the creation of superamphiphobic coatings that combine superhydrophobic and superoleophobic properties through a simple preparation strategy is desirable. In this study, we successfully developed an organic-inorganic hybrid superamphiphobic coating on Q235 carbon steel using aluminum oxide nanoparticles, organosilanes, and waterborne epoxy resin via a versatile spray-coating technique. The coating exhibited high contact angles (> 151°) and low sliding angles (< 7°) for water and oil liquids, demonstrating excellent superamphiphobic characteristics. Electrochemical tests demonstrated significant improvements in charge transfer resistance and low-frequency modulus for the superamphiphobic coating. The corrosion potential shifted positively by 590 mV, and the corrosion current density decreased by four orders of magnitude. Additionally, the coating endured 480 h of salt spray and 2400 h of outdoor atmospheric exposure, showcasing superior anti-corrosion capacity. Freezing tests of water droplets at –10 °C and –15 °C confirmed that the coating significantly prolonged the freezing time with reduced ice adhesion strength. We believe that the designed superamphiphobic coating with integrated functionalities of self-cleaning, anti-corrosion, anti-icing, and anti-liquid-adhesion can provide important solutions for extending the lifespan of materials in marine and industrial environments.

Flexibility and abrasion tolerance of superamphiphobic coatings with rigid core–shell particles

Superamphiphobic coatings maintain surfaces clean even facing severe oil contamination, which is crucial for ensuring the lifespan of materials in highly polluted environments. Achieving excellent wear resistance and flexibility individually on superamphiphobic surfaces is relatively simple, but simultaneously obtaining both properties is challenging and often requires compromises. In this study, we develop an innovative approach inspired by “overcoming firmness by gentleness” to create superamphiphobic composite coatings with flexibility and abrasion tolerance. This innovative strategy combines a soft polyurethane resin with rigid diatomite/aluminum hydroxide (core–shell) particles, resulting in a coating structure resembling karst topography. Depositing aluminum hydroxide enhances the reactivity and content of hydroxyl groups on diatomite particles, simultaneously improving the hardness and 1H,1H,2H,2H-Perfluorodecyltrichlorosilane (FDTS) grafting degree of the core–shell particles. Residual hydroxyl groups on the semi-fluorination core–shell particles chemically bond with the isocyanate groups in the waterborne polyurethane resin, leading to enhanced crosslinking density and improved wear resistance of the coating. The top coating of F-SiO2 particles leads to a reduction in the surface energy of the core–shell coating. The obtained core–shell coating demonstrates excellent oil resistance even after 800 cycles of Taber abrasion under a load of 250 g and 1000 cycles of 360° bending, demonstrating remarkable wear resistance and flexibility simultaneously. This approach provides valuable insights for developing superamphiphobic composite coatings with flexibility and abrasion tolerance and opens new possibilities for their applications in flexible electronics and droplet manipulation.

Heating repairable superamphiphobic coatings for long-lasting antifouling application

Superamphiphobic materials exhibit broader applications and possess greater potential compared to their superhydrophobic counterparts. Therefore, it is crucial for superamphiphobic coatings to exhibit applications while maintaining a long service life. To address this challenge, the surface of natural clay kaolin particles was modified through the reaction of ethyl orthosilicate and 1 H, 1 H, 2 H, 2 H -perfluorodecyl triethoxysilane to form organic-inorganic cage fluorinated polyhedral oligomeric silsesquioxane (fluoroPOS) modifiers. Subsequently, antimicrobial ZnO nanoparticles were prepared in situ using hydrothermal methods. Finally, a durable superamphiphobic coating was achieved by physical blending of a polydimethylsiloxane (PDMS) solution with the superamphiphobic powder. Experimental results demonstrate that the as-prepared ZnO/kaolin@fluoroPOS/PDMS coatings are resistant to water, milk, coffee, soy sauce, tea, sunflower oil, lubricant base oils, and other everyday liquids at contact angles greater than 150 degrees, demonstrating superior superamphiphobic and self-cleaning properties. Moreover, the coatings can withstand harsh external environments such as strong acid and alkali chemical corrosion, high temperature heating, photo-radiation aging, mechanical friction and wear, and show good durability. More importantly, the low surface energy fluoroPOS can spontaneously migrate from the interior of the coating to the surface when exposed to heat, thus restoring their impaired superamphiphobic properties. The coatings also have good antimicrobial adhesion due to the incorporation of ZnO nanoparticles. In addition, coatings can be fabricated on a variety of soft and hard substrate materials, such as cotton fabrics, sponges, aluminum sheets, and wood. Therefore, the repairable and durable superamphiphobic antifouling coatings constructed in this study are expected to find applications in many areas, such as building coatings, oil and gas pipelines, fluid drag reduction, and biological anti-corrosion.

Superhydrophobicity transfer effect in superwetting coatings for strengthening anti-pollution flashover performance

Superhydrophobic (SH) and superamphiphobic (SAP) coatings have been viewed as an alternative to conventional hydrophobic room temperature vulcanizing (RTV) silicone rubber coatings in anti-pollution flashover application. However, being one of the most important properties in RTV-based anti-flashover materials and devices, the hydrophobicity transfer property was rarely documented for SH and SAP coatings, which restricts their practical applications in environments with heavy contamination. Herein, we propose for the first time a superhydrophobicity transfer effect in superwetting (SW) coatings (e.g., SAP and SH coatings) containing low-surface-energy molecules (e.g., polydimethylsiloxane (PDMS)) as a migratory reagent. When the surface is stained by artificial simulated pollutants, PDMS molecules can migrate from the coating to the contamination layer, followed by a surface modification. Through this process, the surface wettability of the contaminant layer gradually evolves from superhydrophilicity to hydrophobicity, and finally to SH state. This evolution is investigated in relation to the amount and species of migratory reagents, migration time, pollution grade, and pollutant species. The superhydrophobicity transfer effect offers the coated glass insulators an outstanding anti-pollution flashover strength. This work can provide a novel and universal protocol to realize a superhydrophobicity transfer property in SW coatings, which may stimulate further investigation and applications in not only anti-pollution flashover but also other fields such as anti-fouling and anti-icing.

Super-amphiphobic arabic gum-based coatings on textile for on-demand oily and dye wastewater treatment

Different membrane materials have broadly been constructed for oil-containing water separation, but most of preparation routes involve corrosive or toxic chemicals and especially many materials have only single superwetting property. Herein, a novel and eco-friendly cellulose-based textile membrane is developed by incorporating the composite coating consisting of arabic gum (AG), attapulgite (APT), and iron (Fe) onto cellulose textiles. The functionalized textile is superoleophobic underwater and superhydrophobic underoil. As a result, the textile prewetted with water or oil can be employed to separate light oil layer/water and heavy oil layer/water mixtures, respectively, and the separation efficiency to the two types of mixtures is larger than 98.3 %. Results also reveal that the decorated textile possesses superior stability and recyclability in purifying oily wastewater. More importantly, such coated textile is capable of filtrating water-soluble contaminants (dyes) from polluted water. Due to the versatility and environmental compatibility of product as well as the accessibility as agricultural and forestry product as raw materials, the advanced textiles may offer effective solutions to oily wastewater purification and water-soluble contaminant removal.

Stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension

Superamphiphobic coatings have great potential in various fields but surfer from weak mechanical stability, low impalement resistance and poor repellency to viscous liquids with low surface tension. Here, we report stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension. By fluorination of silica (F-silica) nanoparticles and solvent induced phase separation of an adhesive, a homogeneous suspension was obtained, which could be readily used for preparing superamphiphobic coatings via spray-coating. The effects of phase separation degree and adhesive/F-silica mass ratio on superamphiphobicity, impalement resistance and mechanical stability of the coatings were studied. The coatings have a hierachical micro-/nanostructure and numerous perfluorodecyl groups on the surface. Thus, the coatings show excellent static and dynamic superamphiphobicity, e.g., high contact angles, low sliding angles, high maximum release height, short solid-liquid contact time and large bouncing height for various liquids with high viscosity and low surface tension. The coatings also show excellent mechanical stability, good chemical and temperature stability. Furthermore, the coatings are applicable onto diverse substrates and could be easily scaled-up.

Preparation of Mechanically Stable Superamphiphobic Coatings via Combining Phase Separation of Adhesive and Fluorinated SiO2 for Anti-Icing.

Superamphiphobic coatings have widespread application potential in various fields, e.g., anti-icing, anti-corrosion and self-cleaning, but are seriously limited by poor mechanical stability. Here, mechanically stable superamphiphobic coatings were fabricated by spraying the suspension composed of phase-separated silicone-modified polyester (SPET) adhesive microspheres with fluorinated silica (FD-POS@SiO2) on them. The effects of non-solvent and SPET adhesive contents on the superamphiphobicity and mechanical stability of the coatings were studied. Due to the phase separation of SPET and the FD-POS@SiO2 nanoparticles, the coatings present a multi-scale micro-/nanostructure. Combined with the FD-POS@SiO2 nanoparticles of low surface energy, the coatings present outstanding static and dynamic superamphiphobicity. Meanwhile, the coatings present outstanding mechanical stability due to the adhesion effect of SPET. In addition, the coatings present outstanding chemical and thermal stability. Moreover, the coatings can obviously delay the water freezing time and decrease the icing adhesion strength. We trust that the superamphiphobic coatings have widespread application potential in the anti-icing field.