Using Nanoimprint Lithography to Create Robust, Buoyant, Superhydrophobic PVB/SiO2 Coatings on wood Surfaces Inspired by Red roses petal

Wood Surface-Embedding of Functional Monodisperse SiO2 Microspheres for Achieving Robust, Durable, Nature-Inspired, Programmable Superrepellent Interfaces

Nature-inspired, robust, durable, liquid-repellent interfaces have attracted considerable interest in the field of wood biomimetic intelligence science and technology application. However, realizing green environmental protection and low maintenance and replacement cost wood surfaces constructed with micro/nanoarchitectures is not an easy task. Aiming at the problem of poor waterproof performance of wood, a silicon dioxide/polydimethylsiloxane (SiO2/PDMS) self-cleaning programmable superhydrophobic coating was biomimetically constructed on the wood substrate by surface-embedded dual-dipping design based on the "substrates + nanoparticles" hybrid principle of the lotus leaf effect. This robust, durable, nature-inspired, self-cleaning, programmable superhydrophobic coating was found to have no observable impact on the original color and texture of the natural wood. The SiO2/PDMS/wood prepared exhibited exceptional liquid repellency and a high static water contact angle (WCA) of 158.5° and a low slide angle (SA) of 10°, including everyday general-purpose droplets, indicating that the introduction of the monodisperse SiO2 microspheres can effectively enhance the superhydrophobic properties of the hydrophilic wood. We applied this strategy to a variety of substrates, including wood-cellulose aerogel and wood-cellulose paper, and demonstrated that the liquid-repellent nature of the self-cleaning superhydrophobic coating remained unchanged. Moreover, the superhydrophobic surface of SiO2/PDMS/wood was preserved even after harsh abrasion conditions, including mechanical damage (sandpaper, sharp steel blade, and tapes), thermal damage (UV irradiation and low/high-temperature exposure such as steaming and freezing), chemical damage, and solvent corrosion (immersion in acid, alkali), demonstrating robust stability of the superhydrophobic coating. Furthermore, the SiO2/PDMS programmable superhydrophobic coating exhibits exceptional exciting self-cleaning and stain-resistant properties, making it offer greater possibilities in terms of scientific challenges and real-world problem-solving at biomimetic smart superhydrophobic interfaces in wood.

Engineering superhydrophobicity: a survey of coating techniques for silicone-based oil-water separation membranes

Oil spills in the ocean and the release of contaminated wastewater from industries cause significant harm to the ecosystem and water sources. To tackle this environmental problem, oil-water mixture separation has been the subject of extensive research over the past few decades. Improving oil absorbents is crucial in removing organic contaminants from wastewater produced by industrial activities. To this end, there is an increasing need for materials that can efficiently and flexibly recover oils from contaminated ocean waters, industrial wastewater, and other sources. Silicones are often used for this purpose because of their exceptional mechanical and thermal durability, as well as their low toxicity. The materials produced from silicones, such as foam, sponge, or substrate, exhibit excellent oil-absorbing properties (maximum oil absorption range, 23.2-77 g/g) and outstanding compression cycles. This article review highlights the advancements in the manufacturing of silicone-based products that have been extensively researched for oil-water separation. Understanding the interdependencies that determine the structure, performance, and manufacturing strategy is essential to producing selective oil absorbents with more commercial potential in the future. Recycling of silicones has also become increasingly important as a goal for the circular economy.

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.

Superhydrophobic Non-Metallic Surfaces with Multiscale Nano/Micro-Structure: Fabrication and Application

Multiscale nano/micro-structured surfaces with superhydrophobicity are abundantly observed in nature such as lotus leaves, rose petals and butterfly wings, where microstructures typically reinforce mechanical stability, while nanostructures predominantly govern wettability. To emulate such hierarchical structures in nature, various methods have been widely applied in the past few decades to the manufacture of multiscale structures which can be applied to functionalities ranging from anti-icing and water-oil separation to self-cleaning. In this review, we highlight recent advances in nano/micro-structured superhydrophobic surfaces, with particular focus on non-metallic materials as they are widely used in daily life due to their lightweight, abrasion resistance and ease of processing properties. This review is organized into three sections. First, fabrication methods of multiscale hierarchical structures are introduced with their strengths and weaknesses. Second, four main application areas of anti-icing, water-oil separation, anti-fog and self-cleaning are overviewed by assessing how and why multiscale structures need to be incorporated to carry out their performances. Finally, future directions and challenges for nano/micro-structured surfaces are presented.

Electrohydrodynamic Nanopatterning: A Novel Solvent-Assisted Technique for Unconventional Substrates

Electrohydrodynamic (EHD)-driven patterning is a pioneering lithographic technique capable of replicating and modifying micro/nanostructures efficiently. However, this process is currently restricted to conventional substrates, as it necessitates a uniform and robust electric field over a large area. Consequently, the use of nontraditional substrates, such as those that are flexible, nonflat, or have high insulation, has been notably limited. In our study, we extend the applicability of EHD-driven patterning by introducing a solvent-assisted capillary peel-and-transfer method that allows the successful removal of diverse EHD-induced structures from their original substrates. Compared with the traditional route, our process boasts a success rate close to 100%. The detached structures can then be efficiently transferred to nonconventional substrates, overcoming the limitations of the traditional EHD process. Our method exhibits significant versatility, as evidenced by successful transfer of structures with engineered wettability and patterned structures composed of metals and metal oxides onto nonconventional substrates.

Advances in the research of carbon-, silicon-, and polymer-based superhydrophobic nanomaterials: Synthesis and potential application

With the rapid development of science and technology, superhydrophobic nanomaterials have become one of the hot topics from various subjects. Due to their distinct properties, such as superhydrophobicity, anti-icing and corrosion resistance, superhydrophobic nanomaterials are widely used in industry, agriculture, defense, medicine and other fields. Hence, the development of superhydrophobic materials with superior performance, economical, practical features, and environment-friendly properties are extremely important for industrial development and environmental protection. Aimed to provide a scientific and theoretical basis for the subsequent study on the preparation of composite superhydrophobic nanomaterials, this paper reviewed the latest progress in the research of superhydrophobic surface wettability and the theory of superhydrophobicity, summarized and analyzed the latest development of carbon-based, silicon-based and polymer-based superhydrophobic nanomaterials in terms of their synthesis, modification, properties and structure sizes (diameters), discussed the problems and unique application prospects of carbon-based, silicon-based and polymer-based superhydrophobic nanomaterials.

Recent Advances in Superhydrophobic Surfaces and Applications on Wood

Superhydrophobic substances were favored in wood protection. Superhydrophobic treatment of wood is of great significance for improving the service life of wood and expanding its application fields, such as improving dimensional stability, durability, UV stability, and reducing wetting. The superhydrophobic phenomenon is attributed to the interaction of micro/nano hierarchical structure and low surface energy substances of the wood surface. This is the common method for obtaining superhydrophobic wood. The article introduces the common preparation methods of superhydrophobic wood material coatings and their mechanisms. These techniques include lithography, sol–gel methods, graft copolymerization, chemical vapor deposition, etc. The latest research progress of superhydrophobic wood material coatings application at domestic and overseas is reviewed, and the current status of superhydrophobic coating application in wood materials and construction is summarized. Finally, superhydrophobic on wood in the field of applied research is presented, and the development trend in the field of functional improvement of wood is foreseen.

Biology and nature: Bionic superhydrophobic surface and principle

Nature is the source of human design inspiration. In order to adapt to the environment better, creatures in nature have formed various morphological structures during billions of years of evolution, among which the superhydrophobic characteristics of some animal and plant surface structures have attracted wide attention. At present, the preparation methods of bionic superhydrophobic surface based on the microstructure of animal and plant body surface include vapor deposition, etching modification, sol-gel method, template method, electrostatic spinning method and electrostatic spraying method, etc., which have been used in medical care, military industry, shipping, textile and other fields. Based on nature, this paper expounds the development history of superhydrophobic principle, summarizes the structure and wettability of superhydrophobic surfaces in nature, and introduces the characteristics differences and applications of different superhydrophobic surfaces in detail. Finally, the challenge of bionic superhydrophobic surface is discussed, and the future development direction of this field is prospected.

Recent Developments in Blood-Compatible Superhydrophobic Surfaces

Superhydrophobic surfaces, as indicated in the name, are highly hydrophobic and readily repel water. With contact angles greater than 150° and sliding angles less than 10°, water droplets flow easily and hardly wet these surfaces. Superhydrophobic materials and coatings have been drawing increasing attention in medical fields, especially on account of their promising applications in blood-contacting devices. Superhydrophobicity controls the interactions of cells with the surfaces and facilitates the flowing of blood or plasma without damaging blood cells. The antibiofouling effect of superhydrophobic surfaces resists adhesion of organic substances, including blood components and microorganisms. These attributes are critical to medical applications such as filter membranes, prosthetic heart valves, extracorporeal circuit tubing, and indwelling catheters. Researchers have developed various methods to fabricate blood-compatible or biocompatible superhydrophobic surfaces using different materials. In addition to being hydrophobic, these surfaces can also be antihemolytic, antithrombotic, antibacterial, and antibiofouling, making them ideal for clinical applications. In this review, the authors summarize recent developments of blood-compatible superhydrophobic surfaces, with a focus on methods and materials. The expectation of this review is that it will support the biomedical research field by providing current trends as well as future directions.

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing. However, in order to have a positive impact on the society, these surface improvements must be applied in real buildings. In this review, the last five years of research in the domain of wood surface improvements and modifications is first presented by sorting the latest innovations into different trends. Afterward, these trends are correlated to specifications representing different normative, ecologic and economic factors which must be considered when expecting to introduce a wood treatment to the market. With this review, the authors hope to help researchers to take into consideration the different factors influencing whether new innovations can leave the research laboratory or not, and thereby facilitate the introduction of new wood surface treatments in the society.

Shape-Deformed Mushroom-like Reentrant Structures for Robust Liquid-Repellent Surfaces

Artificial liquid-repellent surfaces inspired by biomimetic structures provide a wide range of functional surfaces for various practical applications, such as self-cleaning, antisticking, oil/water separation, and droplet manipulation. However, functional biomimetic structures cannot be fabricated using conventional techniques. For example, mushroom-like topologies on the skin of springtails, which are referred to as "doubly reentrant structures," have attracted significant attention owing to their extraordinary liquid-repellent properties. Current methods of fabricating these reentrant structures have several limitations, such as complex material systems, processing steps, and additional chemical treatments. This study proposed a simple micro-shape-deformed approach to fabricate mushroom-like reentrant structures by digital light processing, a three-dimensional (3D) printing technique, with volumetric shrinkage. The nonuniform cross-linking process and light propagation during photopolymerization caused the deformation of the topological patterns atop the micropillar arrays, resulting in bent structures for mushroom-like shape-deformed microarchitectures. This 3D-printed shape-deformed microstructure exhibits a highly stable liquid repellency without perfluorinated coatings.

Bio-inspired wettability patterns for biomedical applications

Benefiting from the remarkable wettability heterogeneity, bio-inspired wettability patterns present a progressive and versatile platform for manipulating and patterning liquids, which provides an emerging strategy for operating liquid samples with crucial values in biomedical applications. In this review, we present a general summary of bio-inspired wettability patterns. After a compendious introduction of natural wettability phenomena and their underlying mechanisms, we summarize the general design principles and fabrication methods for preparing artificial wettability materials. Next, we shift to patterned surface wettability with an emphasis on the fabrication approaches. Then, we discuss in detail the various practical applications of wettability patterns in the biomedical field, including cell culture, drug screening and biosensors. Critical thinking about the current challenges and future outlook is also provided. We believe that this review would propel the prosperous development of bio-inspired wettability patterns to flourish in the field of biomedical engineering.

Preparation of Fluorine-Free Superhydrophobic Paper with Dual-Response of Temperature and pH

Although various superhydrophobic materials have been manufactured and effectively used for oil–water separation, it is still highly desirable to explore materials which are eco-friendly, low-cost, and multifunctional. In this paper, a stable copolymer solution was prepared from the fluorine-free superhydrophobic copolymer with dual-responsiveness of temperature and pH. The functional superhydrophobic paper was prepared by immersing paper in copolymer solution by the dip-coating method. The surface element and structure analysis of the prepared superhydrophobic paper shows that the dual-responsive copolymer adheres successfully to the surface of the paper without destroying the fiber structure of the paper. At pH ≥ 7 and T > 25 °C, the paper has a good superhydrophobic performance, while under the conditions of pH < 7 and T < 25 °C, the paper comes into a hydrophilic state. Therefore, the dual-responsive superhydrophobic paper is more likely to adapt to the complicated oil-water separation environment than the single-response.

Fabrication of Robust Water-Repellent Technology on Cotton Fabric via Reaction of Thiol-ene Click Chemistry

A robust superhydrophobic fabric coating was fabricated on cotton fabric under UV light, which was achieved by convenient surface modification with mercaptopropyltriethoxysilane, tetramethyltetravinylcyclotetrasiloxane, and octadecyl mercaptan. The modification of cotton fabric with 3-mercaptopropyltriethoxysilane introduces reactive mercapto groups, after which 2,4,6,8-tetramethyltetravinylcyclotetrasiloxane reacts with mercapto groups, and octadecyl mercaptan provides microscale roughness. The nonpolar carbon chains of thiol cause the cotton to have a low surface energy. As reported, the combination of microscale roughness with low surface energy has a superhydrophobic effect on cotton, which leads to a high contact angle of 161.8° and sliding angle of 8°. Infrared spectroscopy, XPS, and SEM tests were used to characterize the chemical structure and morphological changes of the surface of cotton fabric before and after click reaction. The fabric after click reaction exhibited an oil–water mixture separation ability owing to its superhydrophobicity. Thus, the finished fabric could be used in the oil–water separation field. Importantly, the superhydrophobic textile displays resistance to laundering, mechanical abrasion, strong acidic and alkaline environments, and UV irradiation. We hope that this study can broaden the real-life applications of cotton fabric.