Durable Superhydrophobic Coatings Research Articles

Construction of Durable, Colored, Superhydrophobic Wood-Based Surface Coatings Using the Sand-In Method.

Highly durable color superhydrophobic coatings have attracted much attention in indoor and outdoor decorative applications. In this paper, colorful superhydrophobic coatings with excellent durability were prepared using silane coupling agent-modified iron oxide as the pigment and polydimethylsiloxane-compounded epoxy resin as the base material by the three-step method of "spraying-sanding-spraying". The method is low cost, has a simple preparation process, enables large-area preparation, and has a restorative function. The use of red, yellow, blue, and green four kinds of modified iron oxides through the single color or multicolor into the sand can be obtained by a variety of color coatings, and silica mixed with a variety of colors can be obtained from light to dark coatings. The coating has excellent superhydrophobicity and self-cleaning ability to withstand sandpaper abrasion, water impact, sand impact, UV exposure, and environmental testing. The coating is suitable for interior and exterior decoration and for protection of wooden buildings.

Durable Superhydrophobic Coatings with Attapulgite for Inhibiting 5G Radome Rain Attenuation.

5G radomes are easily wetted and stained by rainfall, which greatly reduces the quality of signal transmission. Superhydrophobic coatings are expected to solve this problem because of their unique wettability, but it is still challenging to develop robust superhydrophobic coatings via simple methods. Here, we report the design of robust superhydrophobic coatings containing oxalic acid-modified attapulgite (MDP) for inhibiting rain attenuation of 5G radomes. First, a homogeneous suspension was prepared by nonsolvent-induced phase separation of a silicone-modified polyester adhesive (SMPA) solution containing fluorinated MDP (F-MDP) nanorods. Superhydrophobic coatings can be easily prepared by spraying the suspension. The effects of phase separation and the SMPA/F-MDP ratio on the surface morphology, superhydrophobicity, and stability of the coatings were systematically investigated. The micro-/nanostructure and low surface energy endow the coatings with excellent static and dynamic superhydrophobicity. Compared with previous studies, the coatings exhibit excellent mechanical stability, flexibility, chemical stability, and pressure resistance due to the combined effects of adhesion by SMPA, self-similar micro-/nanostructures, reinforcement by the MDP nanorods, etc. Consequently, the coatings show good performance in preventing rain attenuation of 5G radomes, an emerging application of Superhydrophobic coatings. We believe that the coatings have great application potential in various fields, including 5G communication.

Preparation of Pressure-Resistant and Mechanically Durable Superhydrophobic Coatings via Non-Solvent Induced Phase Separation for Anti-Icing.

Inspired by the lotus leaf effect, superhydrophobic coatings have significant potential in various fields, However, their poor pressure resistance, weak mechanical durability, and complex preparation processes severely limit practical applications. Here, a method for preparing pressure-resistant and durable superhydrophobic coatings by simply spray-coating a phase separation suspension containing fluorinated silica nanoparticles and polyolefin adhesive onto substrates is introduced, which forms superhydrophobic coatings with a porous and hierarchical micro-/nanostructure. The resulting superhydrophobic coatings exhibit outstanding pressure resistance, maintaining a Cassie-Baxte state after 18 days of submersion in 1 m of water. Furthermore, the coatings demonstrate remarkable mechanical durability, withstanding 200 cycles of Taber abrasion, 100 cycles of tape-peeling, and 750g of sand abrasion. The coatings also show excellent chemical stability, enduring long-term immersion in corrosive liquids and 120 d of outdoor exposure. Additionally, the coatings display excellent anti-icing properties and can be applied to various substrate surfaces. This approach improves on the limitations of conventional superhydrophobic coatings and accelerates the application of superhydrophobic coatings in real-world environments.

A surfactant-mediated dynamic protection strategy for 100% waterborne fabrication of durable superhydrophobic coatings

Waterborne preparation of superhydrophobic coatings now becomes strongly favored because of its environmental and health friendliness. However, the huge surface energy difference between low surface-energy components and water still poses a challenge for achieving their co-dispersion. Here, a surfactant-mediated protection strategy is proposed to achieve well dispersion of both SiO2 nanoparticles and perfluorosilane in water as well as block their conjugation, thereby fabricating a 100% waterborne F-FC-SiO2 suspension with high homogeneity and dispersion stability. During the painting and drying process, demulsification spontaneously triggers the deprotection and enables sufficient covalent conjugation between perfluorosilane and SiO2, thus achieving a superhydrophobic coating. This supramolecular protection/deprotection approach enables high compatibility of the F-FC-SiO2 suspension with versatile waterborne polymer emulsions (e.g., waterborne polyurethane, waterborne polysiloxane, and waterborne epoxy resin) to fabricate durable superhydrophobic coatings. The resulting composite coating can impart super-repellency to various substrates against aqueous solutions and multiple oils, displaying high antifouling and self-cleaning properties, as well as resistance to extreme mechanical abrasion and weathering. This work provides a promising approach for the convenient production of totally waterborne superhydrophobic coatings.

Latex-Bridged Inverse Pickering Emulsion for Durable Superhydrophobic Coatings with Dual Antibacterial Activity.

There is agreement that every colloidal structure produces its own set of unique characteristics, properties, and applications. A colloidal phenomenon of latex-bridged water in a dimethyl carbonate (DMC) Pickering emulsion stabilized by R202 hydrophobic silica was investigated for its ability to act as a superhydrophobic coating (SHC) for cellulose substrates. First, various emulsion compositions were screened for their stability and droplet size. The final composition was then cross-examined by cryogenic scanning electron microscopy and optical and fluorescent microscopy to verify the colloidal structure. The drying pattern of the coating was investigated by using labeled samples under a fluorescent microscope and by scanning electron microscopy on a paper substrate. After the final ∼3 μm of dry coating was applied, it exhibited superhydrophobicity (advancing contact angle = 155°) and full functionality after 5 min at room temperature (RT). Coated samples maintained superhydrophobicity after 20 abrasion cycles and mechanical integrity after 50 s of water immersion. The SHC-coated paper demonstrated compatibility with a standard laser printer, and the coated paper demonstrated superhydrophobicity after printing. Finally, a propolis/DMC extract was produced and then analyzed by gas chromatography-mass spectroscopy (GC-MS) and infused into the SHC (PSHC). The newly formed PSHC demonstrated its ability to act effectively against E. coli biofilm and S. aureus planktonic cells and reduce their viability by over 90% and 99.99%, respectively.

Enhancing durability of superhydrophobic surfaces via nanoparticle-induced bipolar interface effects and micro-nano composite structures: A femtosecond laser and chemical modification approach

Superhydrophobic coatings are vital in energy, aerospace, and chemical engineering, while their complex preparation and limited durability hinder widespread application. Therefore, inspired by the unique structures of hydrophobic cotton surfaces and mosquito eyes in nature, a durable aluminum alloy superhydrophobic surface is developed using a combination of femtosecond laser and chemical modification methods. Initially, porous microneedle micro-nanostructures are ablated on the surface of the aluminum alloy via femtosecond laser technology. Then, epoxy resin modified with γ-aminopropyl triethoxysilane (KH550) forms a covalently bonded intermediate layer. Finally, biphasic silicon dioxide (BP-SiO2) nanoparticles modified by hexadecyltrimethoxysilane (HDTMS) are used to construct the top hydrophobic layer. The covalent interface interactions between the aluminum alloy substrate and the intermediate layer, as well as between the intermediate layer and the top layer, significantly enhance the durability of the superhydrophobic surface. The prepared F-M@KH-EP/BP-SiO2 coating exhibits outstanding superhydrophobic properties, with a water contact angle (CA) as high as 168.56° and a sliding angle (SA) as low as 1.52° More encouragingly, the composite coating maintains its excellent water resistance even when subjected to harsh mechanical durability damage, including sandpaper wear, tape stripping tests, water drop and sand impact tests. Moreover, the prepared coatings maintain distinguished non-wettability in harsh operating conditions such as corrosive liquid environments, ultraviolet radiation, ultrasonic vibration, etc. Additionally, the coating demonstrates remarkable self-cleaning properties. Superhydrophobic surface durability is significantly enhanced by combining nanoparticle-induced bipolar interface effect and micro-nano structures. These findings provide theoretical reference for the design and application of durable superhydrophobic coatings.

A facile preparation of durable superhydrophobic PFA coatings with superior anti-icing, anti-corrosion and self-cleaning performance

The potential of superhydrophobic coatings for various applications has been widely recognized. However, preparing durable superhydrophobic coatings on metal surfaces remains a significant challenge. Perfluoroalkoxy Alkane (PFA), a fluorine-rich material, has recently emerged as a promising candidate for constructing superhydrophobic coatings. In this study, a mechanically stable superhydrophobic PFA coating was prepared using a simple combination of electrodeposition and annealing. The prepared PFA coating displays excellent water repellency, as evidenced by a water contact angle of 171 ± 0.3° and a sliding angle of 1.0 ± 0.4° The water contact angle of the coating only decreases by 0.6°after undergoing 400 tape stripping tests, indicating the remarkable stability. The PFA coating significantly prolongs the freezing time of water droplets on a cool surface at temperatures of -6 °C, -8 °C, and -10 °C, with improvements of 19.4, 72.5, and 47.8 times respectively. The corrosion current density on the coated surface is reduced by four orders of magnitude compared to bare aluminum alloy, and the PFA coating exhibits a high inhibition corrosion efficiency of 99.995 %. Furthermore, the coating possesses exceptional self-cleaning performance by repelling dirt particles and maintaining a clean surface. Consequently, the developed superhydrophobic PFA coating holds significant promise for long-lasting anti-icing, anti-corrosion and self-cleaning applications.

Facile and sustainable upcycling of fly ash into multifunctional durable superhydrophobic coatings

Fly ash (FA), a hazardous byproduct of coal combustion in power plants, poses significant environmental and health risks due to improper disposal and utilization. This study introduces a facile, sustainable, and cost-effective method for converting FA into a robust superhydrophobic material for various substrates. -FA particles are modified with polydopamine (PD) in water and covalently grafted with octadecylamine (ODA) via the Michael Addition-Schiff Base reactions, resulting in robust superhydrophobic FA (SH-FA) with a water contact angle (WCA) of 163° (±3.1). When applied as a coating to jute, cotton, polyester fibers, PU sponge, and wood, they became superhydrophobic, with WCAs ranging from 154.7 to 161.2° except for the wood substrate, which achieved a WCA of 132° (±3°). The coated polyester fabric exhibited remarkable durability, retaining consistent WCA values after 70 abrasion cycles, 75 adhesive tape peelings, and 20 detergent washing cycles. It also showcased excellent self-cleaning properties, effectively repelling dust and various liquids. Additionally, the coated PU sponge demonstrated exceptional performance in separating oil from different oil/water mixtures, achieving rapid separation of organic solvents within seconds and maintaining a separation efficiency of over 98% even after 12 reuse cycles. These results indicate the potential for transforming FA through effective management.

Study on the construction of durable superhydrophobic coatings using simple spray coating method and their underwater drag reduction performance

Superhydrophobic surfaces have significant applications in industrial and chemical fields. However, their current mechanical stability and underwater durability are insufficient, limiting their widespread application. This study successfully developed a durable superhydrophobic coating suitable for various substrates using a simple one-step spraying technique. By thoroughly investigating the effects of SiO2 concentration and curing temperature on the coating's wettability, underwater durability and mechanical stability, the preparation process was optimized. The prepared superhydrophobic coating achieved a contact angle (CA) of 159.6° and a sliding angle (SA) of less than 1°. In tests of underwater immersion, sandpaper abrasion, repeated water impact, corrosion resistance and ultraviolet (UV) resistance, the coating demonstrated excellent underwater durability, mechanical stability, chemical stability and UV stability. Furthermore, when applied to the steel sphere, the superhydrophobic coating exhibited significant drag reduction effects underwater, reducing the drag coefficient by approximately an order of magnitude and achieving a drag reduction efficiency of 79.1 %. Numerical simulations using STAR-CCM+ showed that the streamlined cavity formed by the superhydrophobic coating effectively suppressed fluid separation, reduced pressure-induced drag, and allowed the superhydrophobic steel sphere to attain a higher terminal velocity. Therefore, the superhydrophobic coating developed in this study has tremendous application potential in underwater drag reduction and is expected to provide effective solutions for energy-saving and drag reduction in fields such as maritime navigation.

Preparation of Durable Superhydrophobic Coatings Based on Discrete Adhesives

Due to the low adhesion observed at the interface between solid and liquid, superhydrophobic coatings hold significant promise for various applications, such as self-cleaning, anti-corrosion, anti-icing, and drag reduction. However, a notable challenge hindering their widespread adoption in these domains lies in their delicate durability. In this study, we propose a straightforward method for preparation. The fluorosilicone resin is initially discretized through a gradual introduction of nonsolvent into its solution, followed by thorough mixing and stirring with silica nanoparticles. The resulting mixture is then sprayed onto the substrate surface after drying, forming a self-similar, porous, and rough structure extending from top to bottom. This process yields a coating exhibiting excellent chemical and mechanical durability simultaneously. Using this approach, we achieved a superhydrophobic coating with a contact angle of 156° and a roll angle of 2.2°, with water droplet adhesion of only 10.8 ± 0.4 µN. Remarkably, the coating maintained excellent superhydrophobicity even after undergoing sandpaper abrasion (10 m), tape peeling (30 times), and prolonged water impact (60 min), showing its robust mechanical stability. Furthermore, following exposure to acid, alkali, and aqueous solutions (7 days), UV irradiation (10 days), and extreme temperature variations (–20 °C to 80 °C), the coatings retained their superhydrophobic properties and exhibited good chemical durability. This method offers a novel approach to enhance the durability and practicality of superhydrophobic coatings.

Robust and Durable Superhydrophobic Coatings with Antipollution Flashover Performance via Silane-Modified Polyurea.

The inadequate hydrophobicity and the degradation in usage seriously hampered the applications of the existing antipollution flashover coatings. In this paper, a superhydrophobic polyurea coating with antipollution flashover ability was fabricated through chemically grafting the silica onto the chains of polyurea by utilizing silane coupling agent and hydrophobic modification. It is demonstrated that the coating exhibits outstanding antipollution flashover performances. Noteworthy, the surface pollution flashover voltage has been increased by 33.8% compared with the room temperature vulcanizing silicone rubber (RTV silicone rubber). In addition, the volume resistivity is above 1.0 × 1012 Ω·m, and the dielectric strength achieves to 28.85 kV/mm, which represents excellent insulating property. Furthermore, the superhydrophobic polyurea coating exhibits outstanding abrasion resistance, adhesion, acid-base resistance, and durability. As a result, it holds great promise for use in preventing pollution flashover in electrical insulators.

Durable Superhydrophobic Surfaces with Self-Generated Wenzel Sites for Efficient Fog Collection.

Harvesting freshwater from fog is one of the possible solutions to the global water scarcity crisis. Surfaces with both hydrophobic and hydrophilic regions are extensively employed for this purpose. Nevertheless, the longevity of these surfaces is still constrained by their delicate surface structures. The hydrophilic zones may become damaged or contaminated after repeated use, thereby compromising their effectiveness in fog collection. The preparation of generally applicable durable superhydrophobic coatings with self-generated Wenzel sites is reported here for long-term efficient and stable fog collection. The coatings are prepared by depositing the poly(tannic acid) coating as the primer layer on various substrates, self-assembly of trichlorovinylsilane into staggered silicone nanofilaments, and then thiol-ene click reaction with 1H,1H,2H,2H-perfluorodecanethiol. The coatings demonstrate remarkable static superhydrophobicity, robust impalement resistance, and stable self-generated Wenzel sites for water droplets. Therefore, the fog collection rate (FCR)of the coatings reaches 2.13g cm-2 h-1 during 192h continuous fog collection, which is triple that of bare substrate and outperforms most previous studies. Moreover, the systematic experiments and models have revealed that the key factors for achieving high FCR on superhydrophobic coatings are forming condensed droplets ≈1mm in critical radius and a Wenzel site proportion of 0.3-0.4.

Durable and Scalable Superhydrophobic Colored Composite Coating for Subambient Daytime Radiative Cooling

Durable and Scalable Superhydrophobic Colored Composite Coating for Subambient Daytime Radiative Cooling

Facile preparation of durable superhydrophobic coating with microstructure self-repairing function by spraying method

Self-healing superhydrophobic coatings have attracted tremendous attention recently, although their practical applications are severely limited by hydrophobic instability and poor structure durability. In this study, a durable superhydrophobic coating was fabricated by a rapid micro/nano structural reconstruction strategy. Carbon nanofibers (CNF) with high aspect ratio were interspersed in fluorosilicone resin (FSR) to construct a uniform network structure. By combining with temperature-responsive carnauba wax (CW) and modified fluororubber (MFR), we obtained a superhydrophobic FSR/CNF/CW/MFR coating with a water contact angle (WCA) of 157 ± 1.2° and water sliding angle (WSA) of 4.5 ± 0.4°. Under the triple synergy of polymer segment migration of FSR, temperature-responsive phase transition of CW, and elastomer rebound repair of MFR, the damaged FSR/CNF/CW/MFR coating surface was rapidly reformed to a new hierarchical micro/nanostructure with short heat treatment (less than 120 s). As a result, for a flat surface, after 1000 abrasion cycles or falling ball impact, a rich micro/nano structure was rapidly reconstructed and superhydrophobic properties were restored. The reconstructed micro/nano multistage structure could effectively capture air, which led to the repaired area exhibiting a charming silver mirror effect and excellent self-cleaning performance. Therefore, this work is expected to provide new insight into the restoration of micro/nanostructures of durable superhydrophobic coatings.

Retraction of “Durable Superhydrophobic Coatings Based on Silica Nanoparticles for 5G Radome”

Retraction of “Durable Superhydrophobic Coatings Based on Silica Nanoparticles for 5G Radome”

Fabricating durable and stable superhydrophobic coatings by the atmospheric pressure plasma polymerisation of hexamethyldisiloxane

The paper was devoted to the results of the study of methods to obtain superhydrophobic film based on the plasma polymerisation of hexamethyldisiloxane (HMDSO) inside the plasma jet at atmospheric pressure. The 3D printing technology was intended for film deposition, which has the advantage of producing superhydrophobic surfaces over a wide range of scales. The effect of synthesis parameters on the hydrophobic properties of the film has been studied. The obtained superhydrophobic films demonstrated stability and resistance in chemical solutions, at high temperatures, under the influence of UV-irradiation and in various weather conditions. The results can be used in various fields, including automotive, construction, electronics, medicine and others, where surface protection against moisture, contamination and corrosion is required.

Robust and applicable superhydrophobic coatings with multi-layer self-similar structure and self-healing properties

To prepare durable superhydrophobic coatings with low-cost is of great importance for its practical application. How to improve the mechanical endurance by a facile method is rarely mentioned in reports. Achieving thicker coating with multi-layer micro-nano structures is critical for obtaining the robust superhydrophobic coating due to the high abrasion resistance to mechanical damage. Herein, a superhydrophobic coating with a multi-layer self-similar structure was fabricated by a facile blending and spraying method. Epoxy resin, neutral silicone glue, polysiloxane and nano-SiO2 are the main composition of the ESPS coating which are important for the multi-layer micro-nano structure construction and adhesion stability between the coating and the substrate. The water contact angle (WCA) and sliding angle (SA) of the ESPS coating were 162.5 ± 0.5° and 4.6 ± 0.4°, respectively. Notably, the ESPS coating with four layers can be abraded with 1500-grid sandpaper under the load of 400 Pa for 24 m. In addition, the prepared samples were put in an outdoor environment for 180 days and exhibited excellent durability and stability. These outstanding properties could be attributed to the hierarchical self-similar structure of the composited coating and the good resistance and adhesion stability provided by polysiloxane. Additionally, the ESPS coating could restore its superhydrophobic characteristic by self-healing realized by the neutral silicone glue in the composition. The good stability and operability of the ESPS coating make it applicable to a wide range of applications.

Mechanically durable superhydrophobic coating of poly(ethyl cyanoacrylate)/SiO2/polydimethylsiloxane with superior abrasion resistance

Mechanical durability of superhydrophobic coating relies on not only the matrix robustness of the coating but also the adhesion stability between the coating and its substrate. Mechanically durable superhydrophobic composite coating of poly(ethyl cyanoacrylate)/SiO2/polydimethylsiloxane (PECA/SiO2/PDMS) was fabricated by pretreating substrate with ethyl cyanoacrylate (ECA) followed by spray-coating composite of PDMS precursors, SiO2 nanoparticles and ECA monomers. In the coating process, the ECAs were in situ polymerized into PECA as an adhesive in between to bind the upper coating with the substrate and inside the composite to strengthen the coating matrix. The as-obtained PECA/SiO2/PDMS coating has strong mechanical stability and excellent superhydrophobicity even after sandpaper abrasion, sand grain impacting, water tumbling over, or acidic/basic solutions corrosion. This adhesive strategy can be applied on all kinds of substrates, providing a facile way to mechanically durable superhydrophobic coatings for expanding the applications.

RETRACTED: Durable Superhydrophobic Coatings Based on Silica Nanoparticles for 5G Radome

RETRACTED: Durable Superhydrophobic Coatings Based on Silica Nanoparticles for 5G Radome

Metallic hierarchical structures uniformly covered with WC@PDMS composite coatings toward comprehensively durable superhydrophobic surfaces

Superhydrophobic surface is one of the most promising materials for the prevention and elimination of ice in daily lives but its durability remains a tremendous problem. Inevitable deterioration on the low-free-energy coating caused by harsh environment restrains their potential applications. Icephobic polymers are more durable than mostly used fluorosilanes for their higher thickness and cohesive strength but difficult to be uniformly modified on rugged micro-nanostructures. In this study, a nanostructured tungsten carbide doped PDMS layer was uniformly covered on aluminum microcones via a hybrid fabrication process combining nanosecond and femtosecond laser ablations and a rotational homogenization process. The prepared superhydrophobic surfaces exhibited excellent water repellency and anti-icing properties in icing-deicing cycles, water flow impacting and freezing-melting cycles. Multiple mechanical/chemical damage tests were performed to test their durability comprehensively. In mechanical tests, the surfaces could withstand linear abrasion length of 240 cm under 5.2 kPa pressure, impacting sand amount of at least 80 g or tape peeling for at least 200 cycles. The chemical durability was elucidated in −40 to 200 °C cycles, 2-day ultraviolet exposure and immersion in different liquids. The proposed hybrid method to form homogenous, ductile and durable superhydrophobic coatings could yield a prospective candidate for applications in anti-fouling and anti-icing.