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a) Optical photograph of color water drop on superhydrophobic coating, b) the image of water jet impacting on coating, c and d) different magnification SEM images of superhydrophobic coating.
Source publication
A lotus leaf like self-cleaning superhydrophobic coating has high demand in industrial applications. Such coatings are prepared by alternative dip and spray deposition techniques. A layer of polyvinyl chloride is applied on glass substrate by dip coating and then spray coated a suspension of hydrophobic silica nanoparticles at substrate temperature...
Contexts in source publication
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... multiple layers of PVC/SiO 2 were applied on glass substrate to obtain desired surface roughness which is the main requirement of extreme water repellency. Figure 1c represents the surface microstructure of three bilayer of PVC/SiO 2 coating, where the aggregated SiO 2 NPs were distributed on the PVC layer. The PVC layer can help SiO 2 NPs to adhere firmly on the coating surface. ...
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... PVC layer can help SiO 2 NPs to adhere firmly on the coating surface. The aggregation of SiO 2 NPs is not uniform and the grain sizes from 5 µm to 100 nm were observed ( Figure 1d). These different size scale grains provide hierarchical surface morphology. ...
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... water drop can only touch a small solid fraction of the coating, as the trapped air pushes away the water drops and not allowing the water drops to wet the inner portion of a rough surface. As shown in the Figure 1a, the water drops hardly stay on the three bilayer of PVC/SiO 2 superhydrophobic coating. Every water drop takes spherical shape at different positions on the coating surface confirming the uniform deposition of PVC/SiO 2 on the substrate. ...
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... superhydrophobic coating was appeared opaque due to the presence of micrometer scaled grains which allows scattering of the visible light. Also the water jet was impacted on the superhydrophobic coating which rebounds off the surface quickly after impacting (Figure 1b). The trapped air in the rough surface resists the water jet to invade the rough structure. ...
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... water jet was immediately spread on uncoated glass slide due to smooth surface structure with hydrophilic nature. On the other hand, the water jet bounced off the superhydrophobic coating as shown in Figure 1b. The air trapped hierarchical structure strongly avoids pinning of water jet on the surface. ...
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We present a facile approach to fabricate superamphiphobic surfaces by spray coating silica-fluoropolymer core-shell particles without substrate pretreatment with an additional binder resin. A series of SiO 2 @poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (SiO 2 @PFMA) core-shell particles with core particles of different sizes were prepared...
Citations
... Hybrid organic-inorganic materials (HYB) containing nanoparticles, inorganic or organic powders, and nano/micro fibres are frequently investigated under this theme. Topical themes, that is, weather/chemical/corrosionresistance, 96,132,192,196,199,201,203,205,206,[211][212][213][214][215][216] wear/abrasion-resistant/adhesion strength 132,190,191,193,194,[197][198][199][200]204,207,208,[217][218][219] and long-term thermal stability 157,171,189,196,207,209,211,213,214,217,[219][220][221][222] were found. Recent research is optimistic about realising robust, reliable, easily reparable 216,223 and long-lasting STFs for a wide range of engineering applications. ...
... Importantly, the dip-coating of inorganic STFs can necessitate hot-dipping, 229 which can reduce process safety and add complexity. Hot dip-coating of superhydrophobic surfaces was mentioned for organic materials such as Alkyl ketene dimer (AKD), 230,231 where the coating temperature ranged from 70 C to 90 C. Stable superhydrophobic surfaces were also achieved by dip-coating a substrate in polyvinyl chloride and spraying several layers of modified silica nanoparticles at surface temperature of 50 C. 204 ...
When discharging latent heat thermal energy storage (LHTES) systems, performance is influenced by the formation and adherence of a solid layer of phase change material (PCM) on heat eXchange (HX) surfaces. Super‐liquid‐repellent thin films (STFs) may be able to reduce solidifying PCM adhesion on HX surfaces during discharging, delay PCM solidification to lower temperatures, and by modifying nucleation sites potentially enable long‐term seasonal thermal storage. Techniques employed previously to fabricate sintered polymeric STF coatings include chemical vapour deposition, dip‐coating, spray‐coating, spin‐coating, layer‐by‐layer (LbL) assembly, sol‐gel, anodizing, electrodeposition, electrospinning, so on. Dip‐coating is considered attractive for fabricating thin films on simple and complex surface geometries due to process maturity, scalability, flexibility and cost‐effectiveness. To identify suitable materials for preparing STFs on metal HX surfaces using the dip‐coating process, more than 200 journal articles published in English during the period 2010 to 2022 were reviewed and the potential role of STFs in LHTES applications was assessed. The review identified key areas and applications stimulating STF material developments and formulations. The dip‐coating of potential STF materials was classified under three major themes driving current research and development (R&D) activities, that is, high performance thin films, eco‐friendly thin films and fundamental research formulations. This review provides a platform from which to develop coatings and HX systems to enable the cost‐effective implementation of STFs for improved heat transfer in future mobile/stationery LHTES systems.
... For 15 mm 4 # MS-II, a decrease of only 1.5 % in the recovery rate was achieved from 1 to 85 h. At 85 h, the oil recovery rate of 15 mm 4 # MS-II (124.1 L/h) was still higher than that of steel disc (88 L/h), with 95 % recovery efficiency, which can be attributed to the super-hydrophobicity, high elasticity and great recyclability of 4 # MS-II [30]. ...
... It has become an important additive for high-temperature resistant materials, ceramic insulation materials, and coatings [1][2][3]. Zirconia exhibits an excellent performance and using it to prepare superhydrophobic coatings can further enhance performance, such as frost suppression [4][5][6], anti-icing [7], and self-cleaning [8,9], and can be applied in aerospace [10,11], medical health [12], solar power generation [13], and other fields. The common methods for preparing super hydrophobic coatings include electrodeposition [14][15][16], laser processing [17,18], immersion [19,20], sol-gel [21], spraying [22,23], etc. ...
Zirconia (ZrO2) is a ceramic material with high-temperature resistance and good insulating properties. Herein, for the first time, the surface of ZrO2 was modified with docosanoic acid (DCA) to improve its self-cleaning and hydrophobic properties. This surface modification transformed the surface of ZrO2 from hydrophilic to superhydrophobic. A two-step spraying method was used to prepare the superhydrophobic surface of ZrO2 by sequentially applying a primer and a topcoat. The primer was a solution configured using an epoxy resin as the adhesive and polyamide as the curing agent, while the topcoat was a modified ZrO2 solution. The superhydrophobic surface of ZrO2 exhibited a contact angle of 154° and a sliding angle of 4°. Scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and other analytical techniques were used to characterize the prepared zirconia particles and their surfaces. Moreover, results from surface self-cleaning and droplet freezing tests showed that DCA-modified ZrO2 can be well combined, and its coatings show good self-cleaning and anti-icing properties on TA2 bases.
... However, it does not allow obtaining sufficiently durable surfaces, especially for coating deposition techniques such as spin-coating, dip-coating, spray-coating. In order to improve the durability of coatings on substrates, the most common way is to prepare a suspension of inorganic nanoparticles in combination with a polymer resin, such as polypropylene [108], polystyrene [ [90,109]], polyurethane [26], Polyvinyl chloride [110], Polyphenylene sulfide [111]. Nanoparticles enable the creation of a rough surface with low energy, while the resin facilitates the adhesion of the nanoparticles to the substrate and improves the durability of the coatings. ...
Superhydrophobic transparent coatings have recently gained significant attention in the solar energy field due to
their ease of preparation, low cost, self-cleaning process, and high effectiveness in reducing dust adhesion to the
surface. However, very few journals have addressed the application of self-cleaning coatings for the solar energy
field due to its complexity. The transparency and the roughness responsible for the self-cleaning feature are two
contradictory parameters; Increasing one parameter strongly implies a decrease in the other, Moreover, the
durability of the coatings is also considered as an essential parameter for their industrial-scale acceptance, as
solar panels are exposed to highly aggressive environments. Therefore, studying superhydrophobic coatings
oriented for solar applications can be challenging. Most reviews reported in the literature provided limited in�formation on the choice of materials, deposition techniques, and synthesis protocols of transparent and super�hydrophobic coatings.
Several reviews have addressed the topic of superhydrophobic coatings, which have various applications such
as water/oil separation, anti-ice, anti-biofouling, self-cleaning and more. However, there are not many reviews
that specifically focus on the development of superhydrophobic coatings for solar applications. This is mainly due
to the transparency constraint required for the solar applications, making this topic particularly challenging. In
the past five years, only five reviews have been published on this subject.
In this review, we discuss in detail the impact of solar panel dust accumulation and its impact on their effi�ciency. Then, we discuss the principle of superhydrophobicity and self-cleaning as well as the principle of
transparent coatings.
... The recovery capacity in water and seawater environments were almost the same. This may be attributed to the anti-corrosive coating of MS@PVC@SiO 2 [63,64]. Thus, it can be inferred that the developed collection equipment has great potential to realize continuous oil/seawater separation in real-world applications. ...
... The recovery capacity in water and seawater environments were almost the same. This may be attributed to the anti-corrosive coating of MS@PVC@SiO2 [63,64]. Thus, it can be inferred that the developed collection equipment has great potential to realize continuous oil/seawater separation in real-world applications. ...
Currently, frequent oil spill accidents caused by transportation, storage, and usage may lead to extensive damage to marine ecosystems. Effective methods for oil spillage recovery from offshore environments are still urgently in demand. A superhydrophobic sponge (MS@PVC@SiO2) was obtained via a facile two-step method for rapid oil adsorption, and a piece of novel collection equipment loaded with MS@PVC@SiO2 was developed for in situ continuous oil/seawater separation. The results showed that MS@PVC@SiO2 exhibits excellent water repellence, compressibility, and durability. Furthermore, the obtained MS@PVC@SiO2 shows high diesel oil adsorption capacity (32 g/g), and excellent recyclability (up to 200 times). The collection equipment demonstrates highly selective oil adsorption capacity and good stability in real seawater. The maximum possible recovery capacity of collection equipment was 557.784 L/h with 98% efficiency, which was much higher than that of commercial disc oil collectors (119.8 L/h). The recovery performance was effectively improved by introducing MS@PVC@SiO2, due to its large specific area and enough storage space. Moreover, even after continuous operation for 58 h in seawater, the collection equipment remained at a high recovery capacity. The results indicate that both MS@PVC@SiO2 and the collection equipment have great application perspectives in practical marine oil spillage recovery.
... In recent years, it has been introduced into the preparation of iron-silicon alloys [5][6][7][8]. The soft magnetic composite material of iron-silicon is mainly obtained by introducing the core-shell heterogeneous structure into the iron-silicon alloy via coating of the particle surface with an insulating medium to increase the resistivity and reduce the iron loss [9][10][11]. ...
Inorganic oxide insulating layers of SiO2 can improve the magnetic properties of FeSi soft magnetic material. Hence, this study explored the coating and growth mechanism of SiO2 by tetraethyl orthosilicate (TEOS) deposition through adsorption on FeSi clusters via molecular dynamics and spin-polarised density functional theory simulations. The results revealed that TEOS molecules were adsorbed on the surface of FeSi cluster mainly via the O in -O-Si (OC2H5)3 groups to Fe sites. The intermolecular interaction of TEOS contributed to the formation of multi-core Si-O structure. H⁺ free radicals frequently diffused and migrated on the FeSi cluster surface, promoting the growth of the crystal nucleus. Four-coordinated [SiO4]⁴⁻ gradually transferred O to the FeSi cluster surface and formed [SiO3]²⁻ and SiO2, which promoted the nucleation and growth of SiO2. The findings presented herein should effectively provide a scientific basis for policymaking in further application of SiO2 materials in the field of soft magnetic materials and those who are interested in the reaction mechanism of FeSi/SiO2 core-shell heterostructure materials.
Graphical abstract
... Lu et al., 2021;Parangusan et al., 2019;C. (Chris) Shi et al., 2016;Sutar et al., 2020bSutar et al., , 2020aWang and Uyama, 2016;Yu et al., 2019;D. Zhang et al., 2020;Zhang et al., 2018). ...
The industrial revolution has led to different types of environmental pollution, including frequent leakage of crude oil to marine waters and the contamination of wastewater with immiscible or emulsified oils and organic liquids from various industrial residues. Hence, developing multifunctional materials for oil/water separation is a field of high significance for the remediation of oil-polluted water. Recently, advanced superwetting materials have been employed for oily wastewater treatment. This review summarizes the recent development in fabricating superhydrophobic/superoleophilic nanohybrid polyurethane, melamine, and cellulose sponges for oil/water separation. The use of organic and/or inorganic nanohybrid materials opens the horizon for designing a diverse and wide range of superhydrophobic sponges due to the synergistic effect between the surface roughness and chemical composition. The discussion is organized based on different classes of low surface energy materials including thermoplastics, thermosets, elastomers, fluorinated polymers, conductive polymers, organosilanes, long alkyl chain compounds, and hydrophobic carbon-based materials. Recent examples for the separation of both immiscible and emulsified oil/water mixtures are presented, with a focus on fabrication strategies, separation efficiency, recyclability, mechanical performance, and durability. Currently, most studies did not focus on the mechanical/chemical stability of the fabricated sponges, and hence, future research directions shall address the fabrication of robust and long-term durable superhydrophobic sponges with proper guidelines. Similarly, more research focus is required to design superhydrophobic sponges for the separation of emulsified oil/water mixtures and heavy crude oil samples. Superhydrophobic sponges can be employed for treatment of oily wastewater, emulsion separation, and cleanup of crude oil spills.
... These amazing properties of natural surfaces are at the basis of the biomimetic approach currently under development both in academia and in the industry. The manufacturing of such hierarchical surfaces inspired from nature is performed through material removal processes such as photolithography [29] or laser ablation [30,31], through material deformation processes such as micro-knurling [32], or through material deposition [33,34]. Within these various technical processes of surface manufacturing, the elaborated surfaces are usually less complex than natural ones. ...
... To propose an interpretation of the wetting contribution on such surfaces, each relevant scale has to be identified. If many inputs have been proposed in literature on human-made hierarchical surfaces [30,41], this point has been less intensively studied in the cases of natural surfaces [34,39]. ...
This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.
... Abdel-Baset et al. [22] showed that the silica nanoparticles (SiO 2 NPs), synthesized by the sol-gel method, could be well dispersed on the PVC films surface in order to obtain transparent PVC-SiO 2 nanocomposite films [22]. Sutar et al. [23] reported the preparation of superhydrophobic coating by applying the multiple layers of PVC/SiO 2 NPs on glass substrate. ...
Transparent and antireflective coatings were prepared by deposition of modified silica
materials onto polyvinyl chloride (PVC) substrates. These materials were obtained by the sol-gel route in acidic medium, at room temperature (25 oC), using different alkoxysilanes with various functional groups (methyl, vinyl, octyl or hexadecyl). Physicochemical and microstructural properties of resulted silica materials and of thin coatings were investigated through Fourier Transforms Infrared Spectroscopy (FTIR), UV-Vis spectroscopy, Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Atomic ForceMicroscopy (AFM) and ellipsometricmeasurements.Wetting behaviors of
the silica coatings were evaluated by measurement of static contact angle against water. FTIR spectra of materials confirmed the high degree of cross-linking that result from the formation of the inorganic backbone through the hydrolysis and polycondensation reactions together with the formation of the organic network. These sol-gel silica coatings showed a reduction in the reflectance (10%) compared with uncoated PVC substrate. AFM reveals that the films are uniform, and adherent to the substrate, but their morphology is strongly influenced by the chemical composition of the coating matrices.
These silica coatings can be useful for potential electronic and optical devices.
