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Nanostructure fabrication on the top of laser-made micropillars for enhancement of water repellence of aluminium alloy
摘要： Fabrication of superhydrophobic surfaces is a popular topic in research and industry due to many potential applications including self-cleaning, anti-icing or drag reduction. Laser micro and nanostructuring is an efficient method to replicate lotus leaves double-scale structures to achieve superhydrophobicity without chemical treatment. Immediately after laser processing, samples are hydrophilic and become hydrophobic in a few days, exposed to atmospheric conditions. This time was significantly reduced by vacuum processing to only 4 h. Two-step fabrication method of superhydrophobic surfaces have been developed using nanosecond laser system. In the first step, large scale micropillars are fabricated and covered by nano-scale protrusions in the following step using defocused laser beam. The nanostructure formation increased the apparent contact angle from 149° to 175°.
关键词： Nanostructures,Aluminium,Superhydrophobic,Fiber laser
更新于2025-09-11 14:15:04
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Study of Infrared Laser Parameters on Surface Morphology and Hydrophobic Properties
摘要： Many studies have shown that super hydrophobic surfaces have been applied to micro–nano structures and low surface energy materials. In the present study, infrared laser scanning and simple salinization modi?cation were used to improve the hydrophobicity of a surface. When the scanning speed was 100 mm/s, the laser power was 30 W and the scanning interval was 200 μm, the apparent contact angle of surface was up to 157°. The assessment of surface characteristics revealed that decreasing scanning speed or increasing laser power were able to improve the hydrophobicity of the surface. After aging treatment, the superhydrophobic surface prepared by this method still had good durability.
关键词： infrared laser,surface morphology,laser parameters,superhydrophobic
更新于2025-09-11 14:15:04
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High Temperature, Transparent, Superhydrophobic Teflon AF-2400/Indium Tin Oxide Nanocomposite Thin Films
摘要： The outstanding properties of Teflon AF-2400—chemical, optical, etc.—inspired us to make modifications to enhance its hydrophobicity. We prepared an AF-2400/Indium Tin Oxide Nanocomposite by a spin coating technique at room temperature, using the AF-2400 polymer as the matrix and indium tin oxide (ITO) nanoparticles as the filler. Different ITON concentrations ranging from 3 mg/ml to 30 mg/ml were prepared to study the effect of nanoparticle loading on the films’ properties and superhydrophobicity. The effect of spin speed and annealing temperature was also studied. Atomic force microscopy, x-ray photoelectron spectroscopy, and UV-vis analysis were employed to characterize the prepared films. The results indicate that the film’s low surface energy and nano/micro-features made it superhydrophobic. Increasing the ITON concentration to 15 mg/ml improved the superhydrophobicity of the composite film by increasing the surface roughness. The coating showed superhydrophobic behavior with a static contact angle around 152o and contact angle hysteresis less than 2o. The nanocomposite films also exhibited excellent thermal stability sustaining temperature as high as 240°C without losing its superhydrophobic behavior. Three models, Wenzel, Cassie-Baxter, and Shuttleworth-Bailey, were used to predict the static contact angle. The results confirmed that the latter model gave the best prediction. In addition to superhydrophobicity, the AF-2400/ITON films coated on a glass substrate showed very high transparency—around 95% in the visible and infrared range. An effective medium theory, the Bergman representation, was used to simulate the transmittance of the AF-2400/ITON nanocomposites. The measured and simulated transmittance values were in good agreement in the visible range. Based on our results, this coating may be highly useful for many practical applications, including solar cell coatings, chemical resistance protective coatings, and more.
关键词： High Temperature,Superhydrophobic,Nanocomposite,Indium Tin Oxide,Transparent,Teflon AF-2400
更新于2025-09-10 09:29:36
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Organic-inorganic composite nanocoatings with superhydrophobicity and thermal stability
摘要： Purpose – This paper aims to investigate the thermal stability and hydrophobicity of difference alkyl chain of silanes with silicon (Si) micro- and nanoparticles. Design/methodology/approach – Sol-gel methods have been used to design superhydrophobic glass substrates through surface modi?cation by using low-surface-energy Isooctyl trimethoxysilane (ITMS) and Ethyl trimethoxysilane (ETMS) solution. Hierarchical double-rough scale solid surface was built by Si micro- and nanoparticles to enhance the surface roughness. The prepared sol was applied onto glass substrate using dip-coating method and was dried at control temperature of 400°C inside the tube furnace. Findings – The glass substrate achieved the water contact angle as high as 154 6 2° and 150.4 6 2° for Si/ITMS and Si/ETMS ?lms, respectively. The Si/ITMS and Si/ETMS also were equipped with low sliding angle as low as 3° and 5°, respectively. The Si micro- and nanoparticles in the coating system have created nanopillars between them, which will suspend the water droplets. Both superhydrophobic coatings have showed good stability against high temperature up to 200°C as there are no changes in WCA shown by both coatings. Si/ITMS ?lm sustains its superhydrophobicity after impacting with further temperature up to 400°C and turns hydrophobic state at 450°C. Research limitations/implications – Findings will be useful to develop superhydrophobic coatings with high thermal stability. Practical implications – Sol method provides a suitable medium for the combination of organic-inorganic network to achieve high hydrophobicity with optimum surface roughness. Originality/value – Application of different alkyl chain groups of silane resin blending with micro- and nanoparticles of Si pigments develops superhydrophobic coatings with high thermal stability.
关键词： Superhydrophobic,Organic coatings,Thermal stability,Coatings,Hierarchical roughness
更新于2025-09-09 09:28:46
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Light-actuated droplets coalescence and ion detection on the CAHTs-assisted superhydrophobic surface
摘要： Coalescence and mixing of the complex chemical reagents on the droplet-based open micro?uidics are considered to be critical steps for the sample processing and the follow-up reactions and chromogenic/?uorescence analyses. Recently, using the light to actuate the droplets coalescence has been demonstrated to be able to create the ?exible, precise and high-throughput optical droplet-based reaction/analysis platforms. Particularly, the photothermal e?ect, which is one of the ?uid-light interactions, is promising in the droplets coalescence by the light-induced phase change. In present study, a contact angle hypothesis traps (CAHTs)-assisted optical droplet-based reaction/analysis platform was developed. With the triple-phase contact line extension caused by the light-heating induced wetting transition, the coalescence of two neighboring droplets on the CAHTs was induced to facilitate the rapid mixing and detection. It was also con?rmed that with the o?-center light heating, the orientable extension of the irradiated droplet was realized, which could increase the critical CAHTs gap required for the occurrence of the droplets coalescence. With the developed platform, an ion detection by processing a chromogenic reaction was presented as a proof of concept. It is believed that this concept has the signi?cant potential in many applications, including biomedicine, pharmacy, clinical diagnosis and chemosynthesis.
关键词： Ion detection,Superhydrophobic surface,Contact angle hypothesis traps,Photothermal e?ect,Droplets coalescence,Orientable extension
更新于2025-09-04 15:30:14
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Facile spraying fabrication of highly flexible and mechanically robust superhydrophobic F-SiO <sub/>2</sub> @PDMS coatings for self-cleaning and drag-reduction applications
摘要： Superhydrophobic coatings treated as surface functional materials are endowed with great application potential with respect to self-cleaning, drag-reduction, anti-icing, etc. In this study, we fabricated a highly flexible and mechanically robust superhydrophobic F-SiO2@PDMS coating through a facile layer-by-layer strategy. It was demonstrated that PDMS played a crucial role of binder for immobilizing the F-SiO2 nanoparticles and improving their adhesion to substrate materials. Meanwhile, the PDMS layer endowed the superhydrophobic coating with superior mechanical flexibility. Finally, the as-constructed superhydrophobic coating exhibited excellent water-repellency with a high water contact angle of 156.5° and low sliding angle of only 2.0°. Furthermore, the water adhesion strength on the superhydrophobic coating was only 2 mN, indicating its ultralow viscous resistance to dynamic moving water droplets. The superhydrophobic F-SiO2@PDMS coating was independent of the substrates without any limitations, and they exhibited high flexibility and mechanical robustness with the elongation ratio reaching 83.3% under the conditions of high superhydrophobicity. Also, the superhydrophobic coating exhibited strong durability under the severe environments of corrosion and mechanical abrasion. Thus, the as-fabricated highly flexible and mechanically robust superhydrophobic F-SiO2@PDMS coating is considered to be an ideal candidate for applications in the fields of self-cleaning and drag-reduction.
关键词： F-SiO2@PDMS,drag-reduction,mechanical robustness,superhydrophobic coatings,self-cleaning
更新于2025-09-04 15:30:14
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Facile Fabrication of Multifunctional ZnO Urchins on Surfaces
摘要： Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report the simple fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, μm-long, tapered nanoneedles radiating from the urchin center. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of 'infant' urchins at the early growth stage and subsequent progressive increases in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH)2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth times were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins—with spiky nanoneedles and at high surface density—on Si substrates was demonstrated. First, bacteria colonization was found to be suppressed on the surface after 24 h incubation in gram-negative Escherichia coli (E. coli) culture, in contrast to control substrates (bare Si and Si sputtered with a 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ～ 0°, could be rendered superhydrophobic with a simple silanization step, characterized by an apparent water contact angle θ of 159° ± 1.4° and contact angle hysteresis ?θ < 7°. The dynamic superhydrophobicity of the surface was demonstrated by the bouncing-off of a falling 10 μL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200–800 nm. The ZnO urchins with a unique morphology fabricated via a simple route at room temperature, and readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.
关键词： superhydrophilic,superhydrophobic,anti-reflective surfaces,ZnO urchins,E. coli,nanostructured surfaces
更新于2025-09-04 15:30:14
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Highly Stable Luminous “Snakes” from CsPbX3 Perovskite Nanocrystals Anchored on Amine-Coated Silica Nanowires
摘要： CsPbX3 (X=Cl, Br and I) perovskite nanocrystals (NCs) are known for their exceptional optoelectronic properties, yet the material’s instability towards polar solvents, heat or UV irradiation greatly limits its further applications. Herein, an efficient in-situ growing strategy has been developed to give highly stable perovskite NC composites (abbr. CsPbX3@CA-SiO2) by anchoring CsPbX3 NCs onto silica nanowires (NWs), which effectively depresses the optical degradation of their photoluminescence (PL) and enhances stability. The preparation of surface-functionalized serpentine silica NWs is realized by a sol-gel process involving hydrolysis of a mixture of tetraethylorthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES) and trimethoxy(octadecyl)silane (TMODS) in a water/oil emulsion. The serpentine NWs are formed via an anisotropic growth with lengths up to 8 μm. The free amino groups are employed as surface ligands for growing perovskite NCs, yielding distributed monodisperse NCs (~8 nm) around the NW matrix. The emission wavelength is tunable by simple variation of the halide compositions (CsPbX3, X=Cl, Br or I) and the composites demonstrate a high photoluminescence quantum yield (PLQY 32-69%). Additionally, we have demonstrated the composites CsPbX3@CA-SiO2 can be self-woven to form a porous 3D hierarchical NWs membrane, giving rise to a superhydrophobic surface with hierarchical micro/nano structural features. The resulting composites exhibit high stability towards water, heat and UV irradiation. This work elucidates an effective strategy to incorporate perovskite nanocrystals onto functional matrices as multifunctional stable light sources.
关键词： colloidal CsPbX3 nanocrystal,superhydrophobic,photostability,assembled hierarchical membrane,serpentine silica nanowires
更新于2025-09-04 15:30:14
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Creation of Superhydrophobic and Superhydrophilic Surfaces on ABS Employing a Nanosecond Laser
摘要： A nanosecond green laser was employed to obtain both superhydrophobic and superhydrophilic surfaces on a white commercial acrylonitrile-butadiene-styrene copolymer (ABS). These wetting behaviors were directly related to a laser-induced superficial modification. A predefined pattern was not produced by the laser, rather, the entire surface was covered with laser pulses at 1200 DPI by placing the sample at different positions along the focal axis. The changes were related to the laser fluence used in each case. The highest fluence, on the focal position, induced a drastic heating of the material surface, and this enabled the melted material to flow, thus leading to an almost flat superhydrophilic surface. By contrast, the use of a lower fluence by placing the sample 0.8 μm out of the focal position led to a poor material flow and a fast cooling that froze in a rugged superhydrophobic surface. Contact angles higher than 150? and roll angles of less than 10? were obtained. These wetting behaviors were stable over time.
关键词： superhydrophilic,superhydrophobic,surface wettability,nanosecond laser surface modification,ABS (Acrylonitrile-Butadiene-Styrene)
更新于2025-09-04 15:30:14