Durable Superhydrophobic Surfaces Research Articles

Preparation and performance study of highly durable silicone rubber superhydrophobic surfaces

Superhydrophobic coatings are widely applied in aerospace and other fields to address issues such as surface drag reduction, anti-icing, and corrosion resistance. Due to the poor durability and unstable performance encountered in the application of most superhydrophobic coatings, we have combined the template method with the spray method to prepare a superhydrophobic surface with excellent durability. Experimental results demonstrate that the contact angle and sliding angle of the prepared surface reached 160.9° and 2.5°, respectively. Importantly, even after undergoing tests such as high-load sandpaper abrasion, tape peeling, and high-speed steel ball impact, the surface maintained outstanding hydrophobic performance. Furthermore, the surface exhibited not only excellent chemical corrosion resistance and self-cleaning effects but also, after experiencing high-load mechanical wear, extended the ice formation delay time to 201 seconds compared to a silicone rubber surface. This study employed a simple and environmentally friendly preparation process, providing robust guidance for the theoretical analysis and practical operation of designing and preparing superhydrophobic surfaces with outstanding durability.

A Route towards Durable Underwater Stable Superhydrophobic Surfaces: PET-Reinforced Candle Soot Layers

Superhydrophobic coating is widely used due to its waterproof and self-cleaning properties. Carbon soot (CS) nanoparticles are naturally superhydrophobic and non-toxic which are superior to other superhydrophobic coating. However, the weak binding force of the CS nanoparticle layers hinders their practical application. In this study, micro-nanostructured PET-CS superhydrophobic coatings were prepared by a simple method. The obtained coatings presented durable superhydrophobicity and underwater stability, which are superior to PDMS-CS coatings and CS layers. The coating surfaces demonstrated superhydrophobicity under a water pressure of 13.72 kPa for up to 16 days. The surface could withstand water flush for more than 15 min. The coatings also demonstrated good mechanical stability and maintained superhydrophobicity after an abrasion length of 8 m. The stable long-lasting underwater superhydrophobic surface is of great importance for marine applications.

Preparation of mechanically durable superhydrophobic aluminum surfaces by LST/MAO and chemical modification

In this paper, a superhydrophobic surface with mechanical durability was prepared on 6061 aluminum (Al) alloy by combining laser surface texturing (LST) and micro-arc oxidation (MAO) techniques followed by chemical immersion treatment. The effects of processing on Al alloys with different texturing spacings on the surface morphology, roughness, surface wettability, and corrosion resistance of the subsequently formed composite coatings were analyzed. The results show that a superhydrophobic surface was obtained with the water contract angle (WCA) of 158.3 ° and the roll-off angle of 9.5 ° at a texture spacing of 300 μm. This was due to the fact that the surface microroughness texturization process created by LST on the surface increased the generation of surface nanostructures, and combined with the natural nanostructure possessed by MAO, unique " double " nanostructure was formed on the surface. This surface structure increased the area of fluoride attachment, reduced the solid-liquid contact area, and decreased the adhesion of droplets to the surface, resulting in higher hydrophobicity. Electrochemical corrosion experiment showed that the corrosion current density of LM-300 was 2 orders of magnitude lower than that of the LM-0 sample, clearly demonstrating better corrosion resistance. In addition, the prepared superhydrophobic surface presented excellent mechanical durability, and in the ceramic zirconia cyclic abrasion experiment, the superhydrophobic surface was able to withstand 61 cycles of abrasion at a pressure of about 2.5 kPa.

Fabrication and characterization of durable superhydrophobic and superoleophobic surfaces on stainless steel mesh substrates

Introduction. This study explores the fabrication of durable superhydrophobic and superoleophobic surfaces on stainless steel mesh, inspired by natural structures like lotus leaves. Achieving superoleophobicity, especially with enhanced durability, is challenging due to the lower surface tension of oils. Methodology. This novel technique involves using Perfluorooctyltriethoxysilane (PFOTES) and silicon dioxide nanoparticles to create re-entrant structures, low surface energy, and high roughness. This cost-effective approach ensures simplicity without requiring expensive equipment. Results. The resulting surfaces exhibit remarkable superoleophobic properties, with hexadecane and soybean oil contact angles reaching 170° and 163.8°, respectively. Scanning electron microscopy confirms successful fabrication, and wear abrasion tests demonstrate mechanical durability, with contact angles remaining high even after cyclic loading and sandpaper abrasion. Conclusion. This study presents a pioneering, cost-effective method for fabricating durable superoleophobic surfaces on stainless steel mesh. These surfaces hold promise for applications in self-cleaning coatings and oil-repellent materials.

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.

Rapid UV-curable preparation of durable soybean oil-based superhydrophobic anti-icing surfaces with excellent photothermal deicing property

Photothermal superhydrophobic coatings are promising for anti-icing/deicing. However, preparing such coatings from environmentally friendly and sustainable strategies is challenging. Herein, a bio-based and durable photothermal superhydrophobic coating is prepared via layer-by-layer strategy. Bio-based methacrylic acid epoxidized soybean oil oligomers are synthesized as an alternative to petroleum-based binders. Meanwhile, efficient photothermal conversion of hydrophobic particles are enabled by oxidative self-polymerization of dopamine to decorate hydrophobic silica particles grafted with hydrophobic long-chain alkanes and photo-curable methacrylic acid moieties. Ultimately, the superhydrophobic coating is achieved by spraying photothermal hydrophobic particles onto an oxygen-inhibited layer of pre-cured bio-based binder followed by thorough photocuring treatment. The coating exhibits powerful water repellency (WCA of 158.2 ± 1.6°, SA of 4.6 ± 0.8°), good robustness, chemical and UV irradiation resistance. Moreover, under NIR laser irradiation (808 nm, 1 W/cm2), the coating features excellent photothermal conversion efficiency (ΔT of 41.0 °C at 30 s) and stable photothermal conversion performance. And in frigid conditions (-15 °C, ∼73 ± 5 % RH), the coating delivers rapid defrosting (few seconds) and deicing (20 μL water droplet melts in 42 s) performance under NIR irradiation of 1 W/cm2. Therefore, the as-prepared coating provides valuable insight into global anti-icing/deicing action.

Research Progress on Superhydrophobic Surface Preparation Methods and Mechanical Durability

Abstract: Superhydrophobic surfaces have great application prospects due to their unique surface- wetting characteristics. However, superhydrophobic surfaces' micro-nano binary rough structure and low surface energy components are easily damaged or lost by wear and grease, which affects their durability and limits their practical application, so it is of great significance to study the durability of superhydrophobic surfaces. The review first introduces the preparation methods and application fields of superhydrophobic surfaces, then sorts out the test methods for the durability performance of superhydrophobic surfaces, methods to improve the durability of superhydrophobic surfaces are summarized， and finally points out some problems in the current research on the durability of superhydrophobic surfaces, aiming to have a comprehensive understanding of the research progress of durable superhydrophobic surfaces, provide some theoretical guidance for the development of durable superhydrophobic surfaces, and look forward to the development direction and trend of durable superhydrophobic surface research in the future. There have been substantial improvements achieved in the preparation techniques to increase the mechanical durability of superhydrophobic surfaces and widen their applications. This review examines pertinent patents and articles on the fabrication of superhydrophobic surfaces from both domestic and foreign sources. The paper introduces the fundamental preparation methods for superhydrophobic surfaces and examines three common techniques: the template method, the spraying method, and the etching method. Additionally, the study discusses these preparation methods and presents future development trends based on the latest research findings. Aiming at the mechanical durability of superhydrophobic surfaces, the test methods for the durability performance of superhydrophobic surfaces under mechanical action are reviewed. The paper also suggests four key methods for enhancing the durability of superhydrophobic surfaces. The refinement of superhydrophobic surface preparation techniques plays a crucial role in enhancing durability and broadening the applications of these surfaces. Additionally, it holds the potential to unlock new possibilities across various domains. The future holds promising prospects for the invention of additional patents and papers focused on superhydrophobic surfaces.

Preparation of Superhydrophobic Fabric Based on Dopamine and Michael Addition under Ultraviolet Light.

This work reports a simple, stable, and environmentally friendly method to prepare durable superhydrophobic surfaces. First, a polydopamine coating is formed by oxidative polymerization of dopamine to form a secondary reaction platform to provide reaction sites for subsequent experiments. We applied a polydopamine layer onto a fiber surface using the Michael addition-reaction-grafted tetrakis (3-mercaptopropionic acid) pentaerythritol ester, followed by the introduction of tetraallyl silane and (mercapto) methyl siloxane-dimethyl siloxane copolymer on the polydopamine by a thiol-ene click-reaction under ultraviolet light. The resulting superhydrophobic Nylon 56 fabric exhibited a 166° static contact angle as well as excellent stability. The surface morphology of all samples was observed by field emission scanning electron microscope, X-ray photoelectron spectroscopy and energy dispersion spectroscopy, and the elemental composition and surface chemical state of the samples were analyzed. It also had the ability of oil-water separation. Fabric with such benefits broadens the applicability and innovation of superhydrophobic textiles for environmental and industrial applications.

Durable superhydrophobic surface in wearable sensors: From nature to application

AbstractThe current generation of wearable sensors often experiences signal interference and external corrosion, leading to device degradation and failure. To address these challenges, the biomimetic superhydrophobic approach has been developed, which offers self‐cleaning, low adhesion, corrosion resistance, anti‐interference, and other properties. Such surfaces possess hierarchical nanostructures and low surface energy, resulting in a smaller contact area with the skin or external environment. Liquid droplets can even become suspended outside the flexible electronics, reducing the risk of pollution and signal interference, which contributes to the long‐term stability of the device in complex environments. Additionally, the coupling of superhydrophobic surfaces and flexible electronics can potentially enhance the device performance due to their large specific surface area and low surface energy. However, the fragility of layered textures in various scenarios and the lack of standardized evaluation and testing methods limit the industrial production of superhydrophobic wearable sensors. This review provides an overview of recent research on superhydrophobic flexible wearable sensors, including the fabrication methodology, evaluation, and specific application targets. The processing, performance, and characteristics of superhydrophobic surfaces are discussed, as well as the working mechanisms and potential challenges of superhydrophobic flexible electronics. Moreover, evaluation strategies for application‐oriented superhydrophobic surfaces are presented.

Perspectives on superhydrophobic surface durability

Superhydrophobicity is a remarkable adaptation observed in various natural surfaces, which can potentially play a crucial role in the efficient functioning of numerous applications. The attainment of long-lasting or “durable” superhydrophobicity has significant implications for global energy production, water conservation, and the overall carbon footprint of industrialized and developing nations. Many applications requiring superhydrophobicity have been limited to laboratory scale experiments due to poor durability. In this article, we discuss important recent advancements and challenges to the development of durable superhydrophobic surfaces, including scalable fabrication, efficacy with low surface tension fluids, and the absence of standardized durability testing methods. To help address these challenges that hinder the implementation of superhydrophobicity, we conclude the article by providing a roadmap that outlines the crucial areas where the community should focus its research and development efforts, both from a fundamental and applied perspective.

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.

Recent Advances in Fabrication of Durable, Transparent, and Superhydrophobic Surfaces.

Transparent superhydrophobic coatings have been extensively investigated due to their ability to provide self-cleaning properties for outdoor applications. However, the widespread implementation of these coatings on a large scale is impeded by the challenges of poor durability and complex fabrication procedures. In this review, the fundamentals and theories governing the mutually exclusive properties of superhydrophobicity, optical transparency, and susceptibility to wear are introduced, followed by a discussion of representative examples of advanced surface design and processing optimizations. Also, robust evaluation protocols for assessing mechanical and chemical stabilities are briefed and potential research directions are presented. This review can offer the research community a better understanding of durable and transparent superhydrophobic surfaces, thereby facilitating their development for real-world applications.

Long-time durability of superhydrophobic surface fabricated by laser texturing and carbon soot

In this work, a novel approach to fabricate highly durable superhydrophobic surfaces (SHSs) with exceptional long-term performance. The demand for real-world applications in various areas such as self-cleaning, anti-bacterial, anti-icing, and water droplet non-wetting behaviour has driven significant attention towards SHSs fabrication. As inspired by the lotus leaf's hierarchical structure, which combines low surface energy and a micro/nanopillar structure to achieve Superhydrophobicity. To achieve this, a fibre laser marking machine has been used to create circular-shaped microstructures on an AISI 420 steel substrate, with a pitch and diameter of 100 µm. To further enhance the surface's water-repellent properties, a unique technique that involves the deposition of carbon soot onto the textured geometry using a candle has been adopted. This resulted in a surface with impressively low surface energy. The most notable aspect of our research is the long-term durability of the fabricated SHSs. Even after two years of exposure to ambient conditions, the surface maintained a maximum contact angle of 158.6°, which is remarkably high, exceeding 150°. This research shows a robust and enduring superhydrophobic surface fabrication method, highlighting its potential for diverse real-world applications.

In-depth analysis of corrosion-resistance and dynamic stability of superhydrophobic copper developed by a green approach

This study gives a systematic analysis of corrosion resistant behaviour of superhydrophobic copper fabricated by two-step (electrodeposition followed by coating) and one-step (coating without electrodeposition) processes using behenic acid. Wetting and corrosion characteristics of coated copper have been continuously evaluated by abrasion with sand paper, immersion in acidic and alkaline solutions, and heating at elevated temperature. Although, wetting properties of coating have been obviously decreased with continuous abrasion, contact with acidic and alkaline ambiance, and hot temperature exposure, but corrosion properties of coated copper have not shown the similar trends which has been discussed through polarisation tests and EIS study in detail. Additionally aforesaid both processes generate durable superhydrophobic copper surface with excellent corrosion-resistant and anti-wetting characteristics; however, a two-step process is proved more efficient than the one-step process and promises to produce anti-wetting coatings for real-world applications.

One-step rapid synthesis of robust superhydrophobic surfaces through acrylate crosslinking/polymerization

A new synthetic approach is proposed to fabricate highly durable and eco-friendly superhydrophobic surfaces using acrylate click chemistry. This approach does not require complex or time-consuming fabrication processes and can be used for the rapid fabrication of durable anti-fouling materials/coatings. The use of long-chain acrylates provides the surface with extreme water repellency, and the resulting surface exhibits long-term stability under various harsh conditions, including prolonged exposure to chemicals, mechanical stress, and physical abrasions. Unlike existing techniques that suffer from poor durability and stability, the proposed method is facile and uses a temperature-initiated acrylate crosslinking/polymerization chemistry that provides a hierarchical morphology with low surface energy to the surface during the reaction. This technique results in highly robust 3D superhydrophobic surfaces that can be easily molded or sprayed onto various flexible and rigid substrates. These surfaces have potential applications in the fabrication of emerging advanced and functional materials. Furthermore, the superhydrophobic gel materials can be extended in 3D print molding using silicone templates, and the spray coating exhibits self-cleaning performance even after harsh physical abrasion. Overall, this new approach is a promising step towards the development of durable and eco-friendly superhydrophobic materials and coatings that can be used in practical applications.

Very simple method to produce superhydrophobic stainless steel surfaces at room temperature

The development of superhydrophobic (SHP) and self-cleaning surfaces has gained significant attention due to their potential applications in various fields. This study presents a rapid, simple, and environmentally friendly method for producing superhydrophobic and self-cleaning surfaces on AISI 347 stainless steel. The process involves mild chemical etching followed followed by Plasma Enhanced Chemical Vapor Deposition (PECVD) deposition of a fluorocarbon film using 1,1,1,2-tetrafluorethane (C2H2F4) as a precursor. The resulting surfaces exhibited contact angles (CA) of up to 164° and sliding angles (SA) as low as 3°. Characterization of the surfaces revealed favorable mechanical properties, including a maximum hardness of 1.1 GPa and an elastic modulus of 9.7 GPa. The method offers potential for large-scale applications and anti-fouling purposes, as demonstrated by initial fouling tests. The findings contribute to the development of cost-effective and durable superhydrophobic surfaces with enhanced mechanical strength and corrosion resistance.

Preparation of durable superhydrophobic composite surface

Surface durability deficit is the most serious challenge confronting superhydrophobic surfaces. The creation of durable superhydrophobic surfaces is therefore of significant importance. In this study, we etched the surface of 1060 aluminum alloy coated with polydimethylsiloxane and nano-fumed silica (PDMS&NF-SiO2) using an infrared nanosecond laser to yield a durable superhydrophobic hybrid surface (SHS). We characterized the composite surface’s static water contact angle (WCA), water roll-off angle (WSA), morphology, and composition using a contact angle meter, scanning electron microscope (SEM), three-dimensional profilometer, energy-dispersive spectrometer (EDS), and Fourier-transform infrared spectroscopy (FT-IR). We also conducted tests for the mechanical durability and thermal stability of the SHS surface using tape peeling, steel wool friction wear, blade scraping, sand impact, and heat treatment. Results indicated that the WCA and WSA of the SHS surface were 158.1° and 6.2°, respectively. The SHS surface maintained its superhydrophobic properties after withstanding at least 150 tape peeling tests, 100 steel wool friction wear tests, 50 blade scraping tests, and a 450 g sand impact test, demonstrating exceptional mechanical durability. The surface WCA and WSA of the SHS after a 30-hour heat treatment at 100 ℃−300 ℃ were 157.4° and 7.6°, respectively, demonstrating good thermal stability. We believe that this study's design and fabrication of superhydrophobic composite surfaces offer new insights for the preparation of wear-resistant and high-temperature resistant superhydrophobic surfaces.

Controllable Construction and Corrosion Resistance Mechanism of Durable Superhydrophobic Micro-Nano Structure on Aluminum Alloy Surface

Aluminum alloy corrosion resistance could be improved by micro-nanostructures on superhydrophobic surfaces, but inadequate mechanical stability remains a bottleneck concern in the sector. Herein, femtosecond laser processing and spray modification techniques are employed to fabricate “armor-style” micro-nanostructures on aluminum alloy surfaces. The construction of durable superhydrophobic surfaces was controllably constructed using this strategy. Applying a spray of hydrophobic nano silica onto the surface of aluminum alloys is an effective method for creating a low surface energy coating, while the femtosecond laser-processed “armor-style” micro-nano structure offers additional adhesion sites for the hydrophobic nano-silica. The findings indicated that the treated surface’s contact angle (CA) reached 152.5° while the slide angle (SA) was only 2.3°, exhibiting favorable superhydrophobic performance. Being worn 100 times with 400# sandpaper, the superhydrophobic surface retained a contact angle above 150°. Electrochemical tests demonstrated significant reductions in the self-corrosion current of superhydrophobic surfaces. Meanwhile, the impedance increased significantly, showing good thermal, mechanical, and chemical stability, enabling better sustainable use of aluminum alloys. These results will serve as a theoretical foundation for the surface protection of aluminum alloys.

Durable superhydrophobic surfaces

Durable superhydrophobic surfaces

Fabrication of a durable superhydrophobic surface with corrosion resistance on copper

In order to fabrication a durable superhydrophobic surface with corrosion resistance, we have constructed a copper oxide layer with a hierarchical structure in situ on the copper surface by using a chemical treatment. The corrosion resistance and superhydrophobic durability of the surface are enhanced due to the chemical stability of the oxide and the stability of the hierarchical structure. The surface morphology, composition and phase structure were characterized by SEM, EDS, XPS, FT-IR and XRD. The superhydrophobicity of the surface was investigated by wettability tests. The superhydrophobicity durability was investigated by acidic and alkaline solution contact angle test, water immersion test, and UV irradiation test. Electrochemical tests were conducted to examine the potentiodynamic polarization curves and electrochemical impedance spectra to investigate the corrosion resistance of the superhydrophobic specimen. The experimental results are as follows. The oxide formed by chemical treatment is CuO. In the oxide layer, the nano-needles are aggregated into bundles, and the bundles are intertwined with each other to form a stable pyramidal hierarchical structure. The superhydrophobic surface has a water contact angle of 160° and a sliding angle of less than 2°. The superhydrophobic surface is chemically stable. The contact angle is greater than 150 ° for both acidic and alkaline test liquids. The superhydrophobic surface retains its hydrophobicity for a long time when immersed in water. After 20 days of exposure to UV light, the surface remains superhydrophobic. The superhydrophobic specimen has a low corrosion rate and high impedance. The superhydrophobic surface is corrosion resistant and can provide corrosion protection to the substrate.