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Adjustable Optical Transmittance of Superhydrophobic Carbon Soot Coatings by in-situ Single-step Control of their Physicochemical Profile
摘要： Soot aerosol formation in the ambient atmosphere, due to inappropriate and incomplete incineration of various fossil fuels or waste materials, has been considered as one of the major anthropogenic contributions to the global warming. However, despite of their adverse environmental impact, the soot nanoparticles are extremely useful in many practical applications if deposited as coatings, since they impart superhydrophobicity of the hosting solid substrate. Here, we unveil novel experimental results on the optical transmittance of superhydrophobic soot coatings with three different physicochemical profiles, synthesized by controlling the atmospheric air flow rate during the combustion of rapeseed oil. The in-depth morphological, chemical and optical analyses using scanning electron microscopy, X-ray photoelectron spectroscopy and spectrophotometry, show relation among the thickness, chemical bonds, morphology and light transmission coefficient (T %) of the soot. In turn, at equal film thicknesses, the gradual decrease of π bonds in the material leads to enhanced light transmittance in the NIR range, while the soot morphology regulates the width of the spectral region with T ?0 %. Our findings demonstrate interconnection between the combustion conditions and the derivative physicochemical properties of the soot coatings, allowing single-step adjustment of their optical behavior, possibly for future underwater optical applications.
关键词： soot,light transmission,physicochemical properties,superhydrophobicity
更新于2025-11-14 15:25:21
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Cross-linked lignin coatings produced by UV light and SF6 plasma treatments
摘要： Lignin is one of the most abundant macromolecules in vascular plants and has been studied for many years due to its high availability and low cost, regarding that lignin is the main by-product of the paper pulping process, and also typically burned as fuel. Despite that, lignin has only a few industrial applications. In this study, we found a simple method for preparing well-defined lignin surfaces. Lignin was extracted from sugar cane bagasse by Soda pulping and its coatings were prepared using solutions with different solvents on various substrates (silicon wafers, paper, steel and glass) by spin-coating. Two methods were tested in order to promote cross-linking on the surface of lignin coatings: SF6 plasma treatment and ultra-violet radiation. Both treatments reduced the amount of hydroxyl groups on the surface leading to more stable, cross-linked coatings as observed by FTIR and thermal analysis. Ultra-violet light radiation turned lignin coatings hydrophilic while stable super-hydrophobic lignin coatings were obtained using SF6 plasma.
关键词： Cross-linking,Surface modification,Coatings,Plasma,Superhydrophobicity,Lignin
更新于2025-09-23 15:23:52
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Design of Chemical Surface Treatment for Laser Textured Metal Alloy to Achieve Extreme Wetting Behavior
摘要： Extreme wetting activities of laser-textured metal alloys have received significant interest due to their superior performance in a wide range of commercial applications and fundamental research studies. Fundamentally, extreme wettability of structured metal alloys depends on both surface structure and surface chemistry. However, compared with the generation of physical topology on the surface, the role of surface chemistry is less explored for the laser texturing processes of metal alloys to tune the wettability. This work introduces a systematic design approach to modify the surface chemistry of laser textured metal alloys to achieve various extreme wettabilities, including superhydrophobicity/superoleophobicity, superhydrophilicity/superoleophilicity, and co-existence of superoleophobicity and superhydrophilicity. Microscale trenches are first created on the aluminum alloy 6061 surfaces by nanosecond pulse laser surface texturing. Subsequently, the textured surface is immersion-treated in several chemical solutions to attach target functional groups on the surface to achieve the final extreme wettability. Anchoring fluorinated groups (-CF2- and -CF3) with very low dispersive and non-dispersive surface energy leads to superoleophobicity and superhydrophobicity, resulting in repelling both water and diiodomethane. Attachment of polar nitrile (-C≡N) group with very high non-dispersive and high dispersive surface energy achieves superhydrophilicity and superoleophilicity by drawing water and diiodomethane molecules in the laser textured capillaries. At last, anchoring fluorinated groups (-CF2- and -CF3) and polar sodium carboxylate (-COONa) together lead to very low dispersive and very high non-dispersive surface energy components. It results in the co-existence of superoleophobicity and superhydrophilicity, where the treated surface attracts water but repels diiodomethane.
关键词： Design,chemical modification,laser texturing,superhydrophilicity,superoleophobicity,superhydrophobicity
更新于2025-09-23 15:21:01
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Roles of chemistry modification for laser textured metal alloys to achieve extreme surface wetting behaviors
摘要： Wetting behaviors of structured metal surfaces have received considerable attention due to the wide range of applications for commercial, industrial, and military uses as well as fundamental research interests. Due to its adaptability, precision, and ease of automation, laser-based texturing techniques are desirable platforms to create micro- and nano-structures, including laser-induced periodic surface structures, or hierarchical structures on a metal substrate. However, micro- and nanostructures alone often do not achieve the desired wettability. A subsequent surface chemistry modification method must be performed to attain target extreme wettability for laser textured metal substrates. This review aims to provide a systematic understanding of the interdependence of surface chemistry modification and physical surface structures formed during the laser-based surface engineering methods. The role of surface chemistry on top of the surface structures is presented to decide the final wetting scenario. Specifically, by controlling the surface chemistry of a laser textured surface, wetting can be modulated from extreme hydrophobicity to hydrophilicity, allowing freedom to achieve complex multi-wettability situations. In each section, we highlight the most fruitful approaches and underlying mechanisms to achieve a fitting combination of surface structures and surface chemistry. Durability and stability of the treatd surface is also discussed in corrosive and abrasive environments. Finally, challenges in current studies and prospects in future research directions of this rapidly developing field are also discussed. This review will provide a comprehensive guideline for the design of laser texturing methods and the fabrication of extreme wetting surfaces for metal alloys.
关键词： superhydrophilicity,superhydrophobicity,metal alloy,Laser surface texturing,chemistry modification,silane treatment
更新于2025-09-23 15:21:01
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Systematic parametric investigation on the CVD process of polysiloxane nano- and microstructures
摘要： Amorphous polysiloxane nano- and microstructures with different shapes can be synthesized from trifunctional organosilane precursors. In the present study, various polysiloxane nano- and microstructures have been produced via a chemical vapor deposition process using ethyltrichlorosilane as precursor. The structure formation and shape are the result of a delicate interplay between temperature, absolute amount of water, and relative humidity. The impact of these reaction parameters during a chemical vapor deposition process has been examined. Experiments have been performed to find a correlation between the reaction conditions and the final shape. Scanning electron microscopy data show that different structures like polysiloxane microrings, microrods, sprouts, nanofilaments, and mixtures of them can be synthesized depending on the reaction conditions. Furthermore, the in-depth comparison of the nanofilament diameters illustrates the dominating influence of relative humidity on structure formation. There is a general trend that at a higher value of relative humidity, structures with a larger diameter are formed independent from the temperature. Here, we clearly differentiate between relative humidity as major and absolute amount of water and temperature as minor important adjusting screws defining the thickness and shape of the resulting nano- and microstructures. Based on these observations, we proof the mechanism of the initial step of structure formation. It is shown that nano- and micro-sized water droplets formed on the substrate surface are likely to act as starting points for structure formation. All results described here strongly confirm the recently published droplet assisted growth and shaping mechanism.
关键词： Superhydrophobicity,Coating,Silicone,Polysiloxane,Surface,Nanofilaments
更新于2025-09-23 15:21:01
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Functionalization of cotton fabric with bismuth oxyiodide nanosheets: applications for photodegrading organic pollutants, UV shielding and self-cleaning
摘要： A multifunctional cotton fabric was prepared by immobilizing bismuth oxyiodide (BiOI) nanosheets on the surface of cotton treated to briefly dissolve surface molecules with upon the low-temperature addition of NaOH and urea (cotton micro-dissolution). Immobilization was accomplished by successive adsorption and reaction (SILAR) at the temperature (* 25 °C). The morphology, structural characteristics, photodegradation ability for organic pollutants, UV shielding, and self-cleaning of the treated fabric were studied. The growth rate and uniformity of the BiOI nanosheets were compared between the treated fabrics and the untreated fabrics. The absorption wavelength of the cotton fabric with BiOI nanosheets was extended to the visible light (* 630 nm) region. Under visible light irradiation, cotton fabric containing BiOI nanosheets (BiOI > 8.4 wt%) showed remarkable photocatalytic ability for degrading rhodamine B (RhB) with a degradation rate of 99% (C0 = 20 mg/L) and 95% after the first and sixth cycle, respectively. The ultraviolet protection factor (UPF) of cotton fabric with BiOI nanosheets was > 50, and its transmittance of ultraviolet A (T(UVA)) was < 5%. The cotton fabric with BiOI nanosheets also exhibited superhydrophobic and self-cleaning properties. Thus, the cotton fabric with BiOI nanosheets has great potential for application as a multifunctional protective material.
关键词： BiOI nanosheets,Visible-light photocatalytic activity,Superhydrophobicity,Ultraviolet protection factor
更新于2025-09-19 17:15:36
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Bioinspired photothermal conversion coatings with self-healing superhydrophobicity for efficient solar steam generation
摘要： Photothermal conversion materials are prone to contamination caused by microorganisms and mud in water and to damages caused by oxidative substances, corrosive liquids and ultraviolet light, thereby greatly limiting the practical application of solar steam generation. Inspired by lotuses, in this study, scalable, chemically and mechanically stable, and conductive photothermal conversion coatings with self-healing superhydrophobicity are fabricated by spraying a mixture of beeswax, multiwalled carbon nanotubes and polydimethylsiloxane. The resulting photothermal conversion coatings exhibit broadband light absorption ability and can thus efficiently generate steam under sunlight irradiation. The integration of superhydrophobicity provides the photothermal conversion coatings with a self-cleaning ability that can prevent the reduction of steam generation efficiency induced by microorganisms and mud in water. In addition, the photothermal conversion coatings are capable of healing damage to their superhydrophobicity through the migration of beeswax, providing long-lasting protection. Furthermore, the photothermal conversion coatings possess an electric steam generation ability, which allows the coatings to continuously generate steam when sunlight is not available. Considering their low maintenance requirement, simple preparation process and high cost effectiveness, photothermal conversion coatings with self-healing superhydrophobicity may be suitable to provide fresh water for remote/disaster areas.
关键词： self-healing,coatings,photothermal conversion,solar steam generation,superhydrophobicity
更新于2025-09-19 17:15:36
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Designing a??Supermetalphobica?? Surfaces that Greatly Repel Liquid Metal by Femtosecond Laser Processing: Does the Surface Chemistry or Microstructure Play a Crucial Role?
摘要： It is demonstrated that the wettability of liquid metal (LM) on a substrate is very different from the water wettability. Superhydrophobic and superhydrophilic silicon and polydimethylsiloxane surfaces, respectively, are obtained by femtosecond laser processing and proper chemical modification. All of the structured surfaces have excellent LM repellence, that is, supermetalphobicity, in spite of superhydrophobicity or superhydrophilicity. The experimental comparison and contact model analysis reveal that surface microstructure actually plays a crucial role in endowing a surface with supermetalphobicity while surface chemistry has a little influence on the formation of supermetalphobicity, because the liquid/solid contact is replaced by a solid/solid contact mode for a LM droplet on a textured substrate. It is believed that the established principle for creating supermetalphobic surfaces will enable to accelerate the application progress of LM materials in flexible circuits and liquid robots.
关键词： superhydrophobicity,eutectic gallium–indium,liquid–metal repellence,femtosecond laser processing,supermetalphobicity
更新于2025-09-19 17:13:59
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High-performance oil-water separation polytetrafluoroethylene membranes prepared by picosecond laser direct ablation and drilling
摘要： The membranes with special surface wettability have attracted considerable attention, especially in the practical applications of oil-water separation. Here, we presented a simple and rapid method of picosecond (ps) laser direct ablation and then drilling to fabricate high-performance oil-water separation polytetrafluoroethylene (PTFE) membrane. It was found that the as-prepared rough PTFE membranes had ca. 0° contact angle (CA) of oil in air and above 150° CAs of water in air or oil, respectively, exhibiting superoleophilicity and under-oil superhydrophobicity. The micropore size of the membranes was less than ca. 180 μm, the corresponding separation efficiencies were over 99.0% for different oil-water mixtures due to the special and rough surface microstructures. Importantly, the separation efficiencies and fluxes of the as-prepared membranes showed no obvious change with suffering heavy erosion or 40 separation cycles, indicating that the membranes had excellent stability and applicability. Additionally, the effect of the special and rough surface on oil-water separation performance was investigated. This work provides a new pathway for the rapid fabrication of high-performance separation membranes.
关键词： Picosecond laser ablation,Superoleophilicity,Polytetrafluoroethylene,Superhydrophobicity,Oil-water separation
更新于2025-09-12 10:27:22
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Reducing Adhesion for Dispensing Tiny Water/Oil Droplet and Gas Bubble by Femtosecond Laser-Treated Needle Nozzles: Superhydrophobicity, Superoleophobicity, and Superaerophobicity
摘要： Three-level microstructures were formed on the stainless steel surfaces by simple femtosecond laser ablation. The structured surfaces exhibit superhydrophilicity in air and superoleophobicity/superaerophobicity in water. After further stearic acid modification, the surfaces turned to superhydrophobicity and underwater superoleophilicity/superaerophilicity. Through this technique, the nozzle of a needle is transformed to possess superwettabilities. When the nozzles were used to release liquid and gas, the sizes of the dispensed water and oil droplets and air bubbles were dramatically reduced. Particularly, we demonstrate that the underwater superaerophobic nozzle could dispense air bubbles in nanoliter volume without the need of reducing the nozzle diameter. The liquid retention at the opening of the needle was also effectively prevented. Therefore, the reduced droplet/bubble size and retention allow us to achieve a dramatically enhanced volume accuracy and resolution when manipulation and transport of aqueous solutions and gases. The femtosecond laser-induced superwetting nozzles can be used in high-resolution liquid transport, inkjet printing, 3D printing, pipettes, medical devices, cell engineering, biological detection, microchemical reactor, and the cleaner of industrial gas emission.
关键词： underwater superoleophobicity,underwater superaerophobicity,superhydrophobicity,femtosecond laser,needle nozzle
更新于2025-09-10 09:29:36