Perfluorooctyltriethoxysilane Research Articles

An integrated approach for developing a durable and superhydrophobic anti-corrosion coating inspired by biomimetic starfish surface structures

Applying superhydrophobic coatings with excellent anti-corrosion, anti-fouling, self-cleaning, antibacterial, and wear-resistant properties is a promising approach to protect metal surfaces. This study presents a novel and cost-effective approach, inspired by the biomimetic structure of starfish, to develop a durable and superhydrophobic coating. Unlike traditional methods, we introduce a meticulously engineered tetrapodal ZnO@SiO2-fluorosilane composite that forms a unique hierarchical micro-nano core-shell structure, reducing surface energy and exceptional performance. The formulation combines perfluorooctyl triethoxysilane (FOTS)-modified SiO2, silicone polyester, and tetrapodal ZnO (T-ZnO) in thermoplastic polyurethane (TPU), resulting in a first-of-its-kind T-ZnO@SiO2-FOTS (ZSF) coating with superhydrophobic properties, demonstrated by a water contact angle of 160°, a sliding angle of 3°, and the lowest surface free energy of 14.50 mN/m, contributing to excellent anti-corrosion properties (corrosion rate of 1.44 × 10−6 mm/year) and a corrosion inhibition efficiency of 99.87 %. In addition, the coating exhibits remarkable mechanical durability, adhesion enhancement, and stability against harsh environmental agents, including salt spray, HCl, and NaOH. Our biomimetic approach leverages the starfish-inspired surface design and highly crosslinked interface to enhance resilience, making this coating more robust under real-world conditions. These results provide a promising pathway for the development of multifunctional coating materials suitable for various solid surfaces.

Modification and Application Performance Study of Ultra-Fine Dry Powder Extinguishing Agent.

Ultra-fine dry powder extinguishing agent (UDPEA) is a promising alternative to Halon agents in aviation firefighting. The formulation of UDPEAs should balance environmental friendliness and practical engineering requirements, including high extinguishing efficiency, excellent flowability, and prolonged anti-reignition. This study investigates the effects of three modification methods (single perfluorooctyl triethoxysilane (FOTS), single N-(3-Triethoxysilylpropyl)perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)amide (PFPE), and a combination of FOTS and PFPE at various mass ratios (2.0:0.4, 1.6:0.8, 1.2:1.2, 0.8:1.6, 0.4:2.0) (g)) on the performance of sodium bicarbonate-based UDPEA. The results indicate that using FOTS or PFPE alone improves the water and oil contact angles, but still fails to meet the required hydrophobicity and oleophobicity standards, and it also reduces the flowability and fire-extinguishing capability. A combination of FOTS and PFPE at the 1:2 ratio yields the best performance, with the water and oil contact angles of 145.169° and 143.542°, respectively, the lowest flowability index (0.224), minimal extinguishing concentration and time (14.183 g/m3 and 1.976 s, respectively), which is only 52.7% and 68.3% of those of the unmodified UDPEA's (26.927 g/m3 and 2.893 s), and the longest anti-reignition time (68.5 s). In addition, the fire-extinguishing mechanisms (chemical inhibition and physical heat absorption) and anti-reignition mechanisms of the modified UDPEA (with the FOTS to PFPE ratio of 1:2) were revealed. This research aims to design an eco-friendly, high-performance UDPEA as an effective substitute for Halon extinguishing agents. These findings can provide valuable insights for evaluating and selecting aviation fire-extinguishing agents.

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.

A rapid two-step process to prepare a high-throughput, efficient, reusable superhydrophobic–superoleophilic stainless steel mesh for oil/water separation

Currently, due to the industrial development, the direct discharge of large amounts of oil-containing wastewater has led to serious water pollution. It is necessary to develop an efficient, durable, and high-throughput material for oil–water separation. To achieve this, we prepared a nickel (Ni) coating with a loose leaf-like micro/nanostructure on the surface of stainless steel mesh (SSM), imparting it with superhydrophobic and superoleophilic properties. The deposition of ions onto the substrate was carefully controlled by adjusting the deposition parameters. Subsequently, the as-prepared Ni coating was further modified using a solution of perfluorooctyltriethoxysilane (PFOTS) in ethanol to obtain a PFOTS/Ni mesh (PNM) with excellent superhydrophobic–superoleophilic properties. Wettability tests revealed that the water contact angle (WCA) and oil contact angle (OCA) of the PNM, prepared under the optimized deposition conditions, were 161 ± 1° and 0°, respectively, with a water sliding angle (WSA) of less than 10°. Importantly, the PNM demonstrated remarkable mechanical stability in blade scratch and tape peel tests, as well as excellent chemical stability in acid-alkali resistance and electrochemical corrosion tests. And, the PNM exhibited remarkable self-cleaning capability. Additionally, PNMit filters displayed outstanding efficiency in separating oil and water (reaching 91.5%) and remarkable durability. The results indicate that the well-designed superhydrophobic–superoleophilic SSM exhibits advantages such as simple fabrication, low cost, high reusability, and strong robustness. It holds great potential for practical applications in the treatment of oily wastewater and oil spill remediation.

Preparation and properties of PTFE@TiO2/epoxy superhydrophobic coating

The problem of bacterial adhesion has been a challenge in everyday life and industry for decades. In this paper, polytetrafluoroethylene(PTFE) micropowder, titanium dioxide(TiO2) nanopowder, ethyl acetate and epoxy resin were sequentially added to a beaker and stirred well, then the nanoparticles were modified using perfluorooctyltriethoxysilane (POTS), and finally superhydrophobic coatings were fabricated on the surface of an aluminium sheet by spraying process. Characterisation was carried out using scanning electron microscopy and contact angle measurement, and the coating wettability, chemical stability and mechanical stability properties were investigated, and finally the coating was tested for antimicrobial properties. The study suggests that the hydrophobicity of the sample was optimal at a contact angle of 163.3° and a rolling angle of 3.2° when the ratio of PTFE micropowder to nano-TiO2 by mass was 1:4 and the ration between POTS and nanoparticles by mass was 12%. The contact angles were 137.8° and 143.6° after 25 and 32 hours of soaked in an anhydrous solution with a pH of 14 and 1, respectively. Most importantly, it exhibits good antimicrobial properties.

A new insight into the design of robust superhydrophobic and fire retardant wood: Breaking the conflicting requirement on adhesives

As a new star of low carbon footprint material, wood with both superhydrophobic robustness and flame retardancy highly boosts its applications in various fields. However, these individual functionalities have conflicting requirements on the interfacial or bulky properties of its surface coating, especially in flammable organic adhesives (such as epoxy resin (EP) and polydimethylsiloxane (PDMS)) and nanoparticle systems. Therefore, breaking the conflicting requirement on adhesives is a crucial and challenging issue for achieving superhydrophobic robustness without impairing flame retardancy. In this work, a structure of three-dimensional (3D) flower-like hydrotalcite (HT) clusters isolated by hierarchical pores was proposed to resolve the conflicting demand. Such kind of structure was fabricated through a one-step thermally-driven method using HT, EP and perfluorooctyl triethoxysilane (PFOES). Benefitting from the release of gaseous ethanol from the inside of wood and its circulation flow among EP and HT during thermally driven process, the HT particles were bonded with small amount of EP and assembled as robust 3D flower-like HT clusters isolated by micro/nano sized pores, rather than embedded in a thick EP coating. This structure significantly reduced the use of flammable EP and increased the loading of flame retardant HT. Therefore, wood with boosting flame retardancy without compromising its own superhydrophobic robustness was achieved (herein named as HT/EP/PFOES wood). Cone calorimetry test showed that the HT/EP/PFOES wood had a 49.33% reduction in the peak of heat release rate (HRR) and a 34.51% reduction of total heat release (THR), which outperformed most of the existing flame retardants and superhydrophobic lignin-cellulosic materials. Meanwhile, its superhydrophobic robustness was not impaired. Together with a facile one-step thermally driven fabrication process, this structure of 3D flower-like HT clusters provided a new insight into fire retardant and robust superhydrophobic wood.

Mechanically Robust and Hydrophobic Poly(3,4-ethylenedioxythiophene)/Silica Hybrid Transparent Film Using Poly(styrenesulfonate-co-allyl methacrylate) as Template Material

We report a simple approach to enhance the mechanical stability and the hydrophobic property of the poly(3,4-ethylenedioxythiophene) (PEDOT) transparent conductive films (TCFs) by an in situ sol–gel hybrid approach. Poly(styrenesulfonate-co-allyl methacrylate) [P(SS-co-AMA)] was used as a template material to synthesize PEDOT:P(SS-co-AMA) aqueous dispersion. PEDOT:P(SS-co-AMA)/silica hybrid films were then prepared by thiol–ene click and sol–gel reactions using silane precursors like 3-mercaptopropyltrimethoxysilane (MPTMS), tetraethyl orthosilicate (TEOS) and perfluorooctyltriethoxysilane (POTES). Pristine PEDOT:P(SS-co-AMA) films on glass showed the electrical conductivity (σ) of 0.07 S/cm, while secondary doping with 5% DMSO increased the conductivity to 77.13 S/cm (transmittance over 92%). As silica is introduced, the electrical conductivity of the PEDOT:P(SS-co-AMA)/silica hybrid films decreased and was in the range of 2.27–76.20 S/cm. Furthermore, the silica hybrid films showed transmittance, >92%; water contact angle, >100°; and pencil hardness, >6H indicating improved hydrophobic property and mechanical stability due to the cross-linked silica network, perfluoro octyl moiety and good compatibility between the organic/inorganic phases. The PEDOT-silica hybrid films with good transparency and electrical conductivity and superior hydrophobic and mechanical properties are suitable candidates for durable optoelectronic device applications.

The Effects of Solvent on Superhydrophobic Polyurethane Coating Incorporated with Hydrophilic SiO2 Nanoparticles as Antifouling Paint

Polyurethane (PU) paint with a hydrophobic surface can be easily fouled. In this study, hydrophilic silica nanoparticles and hydrophobic silane were used to modify the surface hydrophobicity that affects the fouling properties of PU paint. Blending silica nanoparticles followed by silane modification only resulted in a slight change in surface morphology and water contact angle. However, the fouling test using kaolinite slurry containing dye showed discouraging results when perfluorooctyltriethoxy silane was used to modify the PU coating blended with silica. The fouled area of this coating increased to 98.80%, compared to the unmodified PU coating, with a fouled area of 30.42%. Although the PU coating blended with silica nanoparticles did not show a significant change in surface morphology and water contact angle without silane modification, the fouled area was reduced to 3.37%. Surface chemistry could be the significant factor that affects the antifouling properties of PU coating. PU coatings were also coated with silica nanoparticles dispersed in different solvents using the dual-layer coating method. The surface roughness was significantly improved by spray-coated silica nanoparticles on PU coatings. The ethanol solvent increased the surface hydrophilicity significantly, and a water contact angle of 18.04° was attained. Both tetrahydrofuran (THF) and paint thinner allowed the adhesion of silica nanoparticles on PU coatings sufficiently, but the excellent solubility of PU in THF caused the embedment of silica nanoparticles. The surface roughness of the PU coating modified using silica nanoparticles in THF was lower than the PU coating modified using silica nanoparticles in paint thinner. The latter coating not only attained a superhydrophobic surface with a water contact angle of 152.71°, but also achieved an antifouling surface with a fouled area as low as 0.06%.

Extraction and Silylation of Cellulose Nanofibers from Agricultural Bamboo Leaf Waste for Hydrophobic Coating on Paper

ABSTRACT Bamboo leaves are a resource of cellulose fibers that can be further developed into value-added products. In this research, cellulose nanofibers were obtained from Tinwa bamboo leaves, and then chemically modified with (i) hexadecyltrimethoxysilane (HDTMS) and (ii) perfluorooctyltriethoxysilane (POTS). The modified nanofibers were then used as a hydrophobic biopolymer coating on paper, as an alternative to commonly used fossil-based coatings. Hydrophobicity in terms of surface and bulk properties of the coated paperboards was investigated. The results showed that the hydrophobic coatings obtained provided a high contact angle up to 141° and a decrease of water penetration speed during immersion up to 94% when using ultrasonic technique. The coated paperboards exhibited color difference values compared with an uncoated paperboard in the range of 0.4 to <2 which is hardly distinguishable from the human eye. These results suggest that a biopolymer obtained from modified bamboo leaves does in fact provide a suitable replacement for hydrophobic coating on paper.

Absorption-Dominant, Low-Reflection Multifunctional Electromagnetic Shielding Material Derived from Hydrolysate of Waste Leather Scraps.

High-performance flexible conductive films are highly promising for the development of wearable devices, artificial intelligence, medical care, etc. Herein, a three-step procedure was developed to produce electromagnetic interference (EMI) shielding, Joule heating, and a hydrophobic nanofiber film based on hydrolysate of waste leather scraps (HWLS): (i) electrospinning preparation of the HWLS/polyacrylonitrile (PAN)/zeolitic imidazolate framework-67 (ZIF-67) nanofiber film, (ii) carbonization of the HWLS/PAN/ZIF-67 nanofiber film, and (iii) coating of the carbon nanofiber@cobalt (Co@CNF) nanofiber film with perfluorooctyltriethoxysilane (POTS). The X-ray diffraction results showed that metal nanoparticles and amorphous carbon had obvious peaks. The micromorphology results showed that metal nanoparticles were coated with carbon nanofibers. The conductivity and shielding efficiency of the carbon nanofiber film with 250 μm thickness could reach 45 S/m and 49 dB, respectively, and absorption values (A > 0.5) were higher than reflection (R) values for the Co@CNF nanofiber film, which indicated that the contribution of absorption loss was more significant than that of reflection loss. Ultrafast electrothermal response performances were also achieved, which could guarantee the normal functioning of films in cold conditions. The water contact angle of the Co@CNF@POTS nanofiber film was ∼151.3°, which displayed a self-cleaning property with water-proofing and antifouling. Absorption-dominant and low-reflection EMI shielding and electrothermal films not only showed broad application potential in flexible wearable electronic devices but also provided new avenues for the utilization of leather solid waste.

Surface modification of metal substrates using dielectric barrier discharge plasma and the wettability study

BackgroundForming endurable coatings on the surface of metals in a simple, green, efficient manner is still challenging. Plasma surface modification offers an effective method to alter metal surfaces’ physicochemical properties and endow them with new functionalities. MethodsA DBD plasma method is presented for the surface modification of metals using perfluorooctyltriethoxysilane (POTS) and polyethylene glycol (PEG 200) as the precursors. Systematic experiments were carried out against galvanized iron to investigate the process feasibility. This method was further expanded to diverse metal substrates to examine the process versatility and practical applications. Significant findingsThe surface of the galvanized iron substrates were successfully modified by the POTS and PEG 200 precursors to form hydrophobic coatings and hydrophilic coatings, respectively. The composition, morphology, surface roughness, and wettability of the metal substrates could be adjusted by the plasma treatment time. The plasma technique exhibits have high efficiency and good versatility in tuning the wettability of different metal substrates. Furthermore, the plasma-modified substrates also displayed improved corrosion resistance via the salt spray test. This work enriches the study of DBD plasma surface modification as an effective method to functionalize metals with desirable properties.

SiC-enhanced polyurethane composite coatings with excellent anti-fouling, mechanical, thermal, chemical properties on various substrates

Polyurethane (PU) coatings with excellent corrosion resistance and wear resistance are regularly used in furniture coating, metal corrosion protection, electronic device protection and other fields. However, due to the shortcomings of low hydrophobicity and thermal stability, PU coatings are limited to be widely used as waterproof and breathable materials. This is expected to be improved by nanoparticles with high thermal conductivity and robust properties, such as silicon carbide (SiC). Here, the SiC-enhanced PU composite coatings modified by perfluorooctyltriethoxysilane (PFOTS) were successfully fabricated by spraying. The dispersion of SiC after chemical grafting modification of PFOTS in PU was significantly improved. The hard SiC particles provided a special micro-nano structure on the surface of the PU coating, altering the wettability of the coating from hydrophilic to superhydrophobic. The 125 wt% F-SiC/PU composite coating showed the best superhydrophobic properties with good wear resistance, anti-stripping ability, thermal stability, salt spray resistance and acid/base resistance, which depends on the uniform dispersion of SiC with high hardness and high thermal conductivity in the PU coating. The 125 wt% F-SiC/PU composite coating can present superhydrophobic properties on different substrates, such as aluminum alloy, ceramic, plastic sheet and filter paper, and have certain anti-fouling properties. This research provides a new strategy for the development of wear-resistant and anti-fouling PU superhydrophobic coatings.

Aluminum anodizing with simultaneous silanization for increased hydrophobicity and corrosion protection

Anodizing and deposition of hydrophobic films are processes used separately to improve the atmospheric corrosion resistance and hydrophobicity of Al alloys used for heat exchangers. In the present work, we assessed the effect of various additives on the sulfuric acid anodizing (SAA) electrolyte, namely ethanol, trifluoroethanol, hexadecyltrimethoxysilane (HDTMS), and perfluorooctyltriethoxysilane (PFOTES). By tailoring the anodizing process, simultaneous growth of a protective porous layer and hydrophobicity increase of AA1100 were achieved in one step. Cell potential transients and XPS surface analysis confirm that silane incorporation into the oxide structure during anodizing enhances the hydrophobic properties of samples anodized in SAA-ethanolic PFOTES electrolytes. When HDTMS is added, a uniform hydrophobic protective coating is produced, but the electrolyte is unstable. The time required for nucleation of pitting corrosion in potentiostatic tests in NaCl increases when ethanol, HDTMS, or PFOTES are incorporated in the anodization bath.

PTFE/EP Reinforced MOF/SiO2 Composite as a Superior Mechanically Robust Superhydrophobic Agent towards Corrosion Protection, Self-Cleaning and Anti-Icing.

Organic resin cross-linking ZIF-67/SiO2 superhydrophobic (SHPB) multilayer coating was successfully fabricated on metal substrate. The perfluoro-octyl-triethoxy silane (POTS) modified ZIF-67 and SiO2 coating was applied on primary coated polytetrafluoroethylene (PTFE) and epoxy resin (EP) via spray coating method. Here, we present that the robust superhydrophobicity can be realized by structuring surfaces at two different length scales, with a nanostructure design to provide water repellence and a microstructure design to provide durability. The as-fabricated multilayer coating displayed superior water-repellence (CA=167.4°), chemical robustness (pH=1-14) and mechanical durability undergoing 120th linear abrasion or 35th rotatory abrasion cycle. By applying different acidic and basic corrosive media and various weathering conditions, it can still maintain superior-hydrophobicity. To get a better insight of interaction between inhibitor molecules and metal surface, density functional theory (DFT) calculations were performed, showing lower energy gap and increased binding energy of ZPS/SiO2 /PTFE/EP (ZPS=ZIF-67+POTS) multilayer coating compared to the ZIF-67/SiO2 /PTFE/EP, thereby supporting the experimental findings. Additionally, such coatings may be useful for applications such as anti-corrosion, self-cleaning, and anti-icing multi-functionalities.

Fabrication of hierarchically textured aluminum-based superhydrophobic surfaces for anti-frosting application

Rational design of solid interfaces with an ability to prevent frost formation is crucial in many industrial systems such as refrigeration, air-conditioning, cryogenics, etc. In this work, we fabricated two hierarchically textured aluminum-based superhydrophobic surfaces by simple steps such as chemical etching and dip/spray coating. We used perfluorooctyltriethoxysilane (PFOTES) and commercial Glaco solution as a hydrophobic coating material. The fabricated substrates have shown excellent superhydrophobicity with a low contact angle hysteresis of below 5°. The frost formation on both the coatings was different despite having similar macroscopic wettability. We analyzed the surface topography and its effects on frost formation comprehensively. PFOTES coated substrate has shown a sweeping mode of drop drainage, whereas the Glaco coated substrate showed the droplet jumping mode. Rapid ejection of condensed microdroplets from the Glaco coated substrate is delayed the frost formation due to the significant reduction in the drop contact time. This study elucidates the dependence of nanostructured coatings over the microstructures during frost formation. The insights from this study are helpful for the fabrication of anti-frosting surfaces for industrial applications.

Condensation of Humid Air on Superhydrophobic Surfaces: Effect of Nanocoatings on a Hierarchical Interface.

Vapor condensation is a well-known phase-change phenomenon observed in nature as well as in different industrial applications. Superhydrophobic surfaces (SHSs) with low hysteresis can efficiently drain off the condensate and rejuvenate the nucleation sites further. In this work, three distinct SHSs were fabricated by nanocoating three hydrophobic agents, viz., perfluoro-octyl-triethoxy-silane (PFOTS), perfluoro-octanoic-acid (PFOA), and commercial Glaco solution on a hierarchical aluminum surface. The surface morphology of all surfaces was investigated, and its effects on the wetting, droplet departure, and overall heat-transfer coefficient (HTC) during condensation phenomena in the humid air (>95% noncondensable gases) were analyzed. The contact angle hysteresis of all three surfaces was very low (∼5°); however, different wetting behaviors were observed during the condensation, depending on the adhesion of the condensate drop with nanoscale textures in the microcavities. Dropwise condensation (DWC) was observed in silane and Glaco-coated surfaces. A gravity-assisted sweeping mechanism removed the condensate from the silane-coated surface. In contrast, the condensate was ejected out of the plane of the Glaco-coated surface by droplet jumping. The PFOA-coated surface has shown DWC initially and floods in the later stages due to highly pinned condensed droplets. This study reports an enhancement of ∼35 to ∼110% in the HTC for the SHS-exhibiting gravity-assisted sweeping mechanism compared to the droplet-jumping mechanism. The present work will provide substantial insights into the fabrication of efficient hierarchical interfaces for water-energy nexus applications.

Enhanced anti-corrosion and microwave absorption performance with carbonyl iron modified by organic fluorinated chemicals

Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coating not only affected the electromagnetic parameters of carbonyl iron, but also improved the impedance matching of materials. Electromagnetic performance test results demonstrated that the microwave absorption performance of CI@PFOTES composite was better than that of carbonyl iron, and its minimum reflection loss was − 40.45 dB at 4.08 GHz with a matching thickness of 3.5 mm. Our work provides a new perspective for preparing composites with good microwave absorption and corrosion resistance in practical applications.

Corrosion Resistance and Formation Mechanism of Anodic Oxidation–Organic Structure Super‐Hydrophobic Self‐Assembled Film

AbstractIn this article, the perfluorooctyltriethoxysilane (POTS) is used as a low surface energy substance to self‐assemble in Al2O3 surface to prepare a corrosion‐resistant composite film by anodization and self‐assembly technology. The morphology, structure, wettability, and chemical composition of the composite film are characterized by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, water contact angle, and X‐ray photoelectron spectroscopy. The corrosion resistance of the composite film is tested through electrochemical test and the neutral salt spray test, and various pollution simulations are performed to test the self‐cleaning performance of the film. The formation mechanism of the film is discussed by quantum chemical calculations. The results show that compared with Al alloy, the AC impedance of the composite film is increased by five orders of magnitude, the corrosion current density is reduced by three orders of magnitude, and the neutral salt spray corrosion test reaches 31 days. Meanwhile, theoretical studies of quantum chemical calculations show that Al2O3/POTS film is adsorbed on the surface of Al alloys through SiOAl chemical bonds. This work puts forward scientific viewpoints and novel design concepts to create effective anti‐corrosion coatings to protect Al alloys, and then expand its potential applications in other fields.

Self-Assembled Monolayers Coated Porous SnO2 Film Gas Sensor with Reduced Humidity Influence.

Metal-oxide sensors, detect gas through the reaction of surface oxygen molecules with target gases, are promising for the detection of toxic pollutant gases, combustible gases, and organic vapors; however, their sensitivity, selectivity, and long-term stability limit practical applications. Porous structure for increasing surface area, adding catalyst, and altering the operation temperature are proposed for enhancing the sensitivity and selectivity. Although humidity can significantly affect the property and stability of the sensors, studies focusing on the long-term stability of gas sensors are scarce. To reduce the effects of humidity, 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane (PFOTS) was coated on a porous SnO2 film. The interconnected SnO2 nanowires improved the high surface area, and the PFOTS coating provided superhydrophobicity at water contact angle of 159°and perfect water vapor repellency inside E-SEM. The superhydrophobic porous morphology was maintained under relative humidity of 99% and operating temperature of 300 °C. The CO gas sensing of 5, 20, and 50 ppm were obtained with linearity at various humidity. Flame detection was also achieved with practical high humidity conditions. These results suggest the simple way for reliable sensing of nanostructured metal-oxide gas sensors with high sensitivity and long-term stability even in highly humid environments.

Facile fabrication of superhydrophobic, flame-retardant and conductive polyurethane sponge via dip-coating

Polydopamine (PDA) from the in-situ polymerization of dopamine and reduced graphene oxide (RGO) were used to construct a PDA/RGO composite coating with micro-nano roughness on the surface of polyurethane sponge (PUS) skeleton. Then, perfluorooctyltriethoxysilane (PFOTES) was grafted onto the surface of PDA/RGO composite coating via the hydrolysis-condensation reaction of PFOTES and the hydroxyl of PDA/RGO composite coating, and the superhydrophobic, flame-retardant and conductive PUS (SFRC-PUS) was finally obtained. SFRC-PUS showed superior anti-droplet adhesion performance with the water contact angle of over 160°. Moreover, SFRC-PUS exhibited excellent flame retardancy. When suffering to fire, no melt droplet was generated in the combustion, and the fire extinguished within 42 s. Furthermore, SFRC-PUS possessed high electrical conductivity and excellent conductive stability. The resistance of SFRC-PUS still remained stable after 1000 loading–unloading cycles in the pressure range of 2–50 kPa. The preparation of SFRC-PUS was simple and efficient, showing great prospect in large-scale preparation of multi-functional waterproof flame-retardant and conductive materials.