Journal of Coatings Technology and Research最新文献

Titanium alloy-based superhydrophobic surfaces have great advantages in terms of self-cleaning and corrosion resistance. To extend the application of titanium alloy, a multifunctional superhydrophobic TA2 titanium alloy was fabricated by anodic oxidation and chemical modification. Regular TiO₂ nanotube arrays were obtained after anodic oxidation and completely covered by 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The water contact angle of superhydrophobic TA2 titanium alloy is as high as 153.4° ± 0.6°, and the contact angle of the surface shows good stability in different pH aqueous solutions and different concentrations of NaCl solutions. At −10 °C, the icing time of superhydrophobic TA2 titanium alloy surface can be extended to 4400 s. Furthermore, the superhydrophobic TA2 titanium alloy still maintains superhydrophobic properties when polished 70 times by sandpaper, indicating that the surface has good friction resistance. Electrochemical impedance spectroscopy results show that superhydrophobic TA2 titanium alloy with a Z′|_f=0.01 Hz value of 84 kΩ cm² has better corrosion resistance compared with the TA2 titanium alloy. These results indicate that the superhydrophobic composite film integrates multiple functions on the surface of TA2 titanium alloy, which greatly expands its application.

Traditional two-component waterborne polyurethane (2K WPU) has low water resistance, which limits its application in the wide field. In this work, fluorine-modified 2K WPU films (2K-WFPUs) were successfully prepared using a fluorine-modified acrylate emulsion as hydroxyl component and a hydrophilically modified polyisocyanate as curing agent. Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analysis indicate that hexafluorobutyl acrylate (HFBA) was successfully introduced into the 2K-WFPUs. The effects of HFBA content on the surface, thermal stability, water resistance, mechanical, and application properties of 2K-WFPUs were investigated. Compared with the unmodified film, with the increase in HFBA level from 0 to 8%, the static water contact angle of 2K-WFPUs increased from 66° to 92°, the surface-free energy decreased from 42.7 to 28.4 mJ m⁻², the water absorption reduced from 15.9 to 9.9%. Thermogravimetric analysis shows that the thermal stabilities of 2K-WFPUs were improved remarkably. Meanwhile, adding HFBA did not weaken the impact resistance, flexibility, and adhesion of 2K-WFPUs and maintained the highest level. The fluorine-modified 2K WPU coatings have potential application in wood furniture and automotive finishing.

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Epoxy-acrylate (EA) core–shell nanoparticles have gained significant attention recently due to their dual unique properties as heterogeneous materials, particularly in coating applications. However, the effect of epoxy (EP) concentration in core layer on mechanical properties is still limited, and the mechanism of how it affects the film's performance is not well understood. In this study, we investigate the effect of varying EP concentration in the core layer on the mechanical properties of nanostructured films containing EA core–shell nanoparticles. The core–shell nanoparticles were synthesized through multistage seeded emulsion polymerization. The transmission electron microscopy (TEM) images revealed similar particle morphology and size in all EA nanoparticles. Differential scanning calorimetry (DSC) analysis confirmed the successful synthesis of core–shell particle morphology with two glass transition temperature (T_g) values (~12 °C and ~ 60 °C) observed for the core and shell layers, respectively. We observed an increase in the T_g values of the shell layer with higher EP content in the core layer. The use of EP-based copolymers raised the T_g values of the shell layer, significantly affecting the film formation behavior and their mechanical properties through interlayer crosslinking. Tensile modulus values for the films ranged from 200 to 500 MPa, marking the highest modulus reported for cast films of EA nanostructured films. Our findings reveal a straightforward and versatile method for producing high-modulus EA nanostructured films with customizable mechanical properties, making the model ideal for enhancing wood coating performance.

In synergy with constructing a sustainable environment, facile reuse of carbon-rich biowastes as inexpensive precursors for the synthesis of value-added functional carbon dots (CDs) has garnered fruitful outcomes. Pistachio shells comprising cellulose, hemicellulose, and lignin were successfully utilized as a carbon source for the synthesis of CDs through carbonization and subsequent hydrothermal method. The methanolic fraction with desirable fluorescence in the visible region obtained after column purification of CDs was further characterized using TEM, EDS, SAED, FTIR, XPS, RS, XRD, and TCSPC techniques. The blue and green emitting CDs were used as colorants to prepare a water-based ink for screen printing. The screen prints on UV dull paper substrate exhibited good colorimetric and density values. The UV-induced yellow fluorescence of the ink film can be used as a security feature to authenticate genuine document/products and data storage.

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The accumulation of microorganisms, algae, mussels, and barnacles on the hull of sea vessels leads to biofouling, surface corrosion, and increased drag as the vessel moves through water costing the marine industry around $15 billion/year. Current commercial traditional antifouling coatings suffer from reduced energy efficiency and short lifespan and contain heavy metals that are toxic to marine organisms and humans. The banning of these coatings is due to environmental concerns, and nonbiocidal alternatives such as polymer-based coatings are being sought after. This review demonstrates emerging promises of hydrogel fouling-release coatings (FRCs) in the marine environment that may be effective against a prevalent amount of biofouling agents. The review also highlights the importance of polymer backbone materials with surface wettability characteristics possessing hydrophobic, hydrophilic, and zwitterionic properties and further discusses emerging antifouling techniques, synthesis of hydrogel, swelling behavior of hydrogel, laboratory assays of hydrogel coating, marine field test, and outlook of hydrogel fouling-release (FRCs) coatings.

In this study, active–passive anticorrosion antistatic epoxy composite coatings containing CeO₂, carbon coated ceria (CeO₂@C), and carbon hollow sphere particles were prepared. Cerium oxide (CeO₂) particles were synthesized through a hydrothermal approach in the presence of polyvinylpyrrolidone as a surfactant to achieve a uniform and semispherical morphology and to improve dispersion stability. Carbon hollow spheres (CHSs) were also fabricated using the surface-modified silica templating method. The structure and morphology of the synthesized particles were analyzed using Fourier transform infrared spectrometry, X-ray diffractometry, Raman spectrometry, and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS). Furthermore, migration of the synthesized particles from the bulk toward the surface was investigated with atomic force microscopy, Raman spectra, and field emission SEM in addition to density, capillary wetting, contact angle, and zeta potential measurements. The results indicated that CHSs migrate toward the surface of the matrix due to its low interfacial tensions leading to a decline in the dielectric constant and electrical resistance, providing a composite with suitable antistatic properties. Moreover, electrochemical impedance spectroscopy and immersion testing were used to estimate the influence of the particles on the coating's anticorrosive property. The results showed that the impedance modulus at low frequency (|Z|0.01 Hz) significantly increased from 3.81 × 10⁶ Ω cm² (pristine epoxy) to 11 × 10⁸ Ω cm² after 40 days of immersion in 3.5% NaCl water solution. As a result of the synergistic protection provided by ceria, CHS, and CeO₂@C particles, composite coatings exhibit superior anticorrosion properties. The ceria particles have an inhibitory effect which forms a passive layer. Furthermore, the CHS and CeO₂@C particles produce a protective barrier prolonging the penetration pathway of corrosive media. Such significant improvements can provide an antistatic coating for designing novel corrosion protection coatings.

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To date, smart surfaces with controllable wettability have received extraordinary attention due to their great importance in both fundamental research and practical applications. Chemical composition and surface topography are the two key factors to affect the wettability of solid surfaces. Applying external stimuli to change the surface chemistry and/or topography is considered to be a valuable approach for driving the transition between hydrophilicity and hydrophobicity of surfaces. In this study, poly o-toluidine nanofibers were synthesized by a facile aqueous/organic interfacial polymerization, and superhydrophobic coatings of poly o-toluidine were prepared via a room-temperature spraying process. The reversible wettability conversion between the superhydrophobic and the hydrophilic state of the obtained poly o-toluidine coating under ultraviolet irradiation and electric stimulation was investigated. From the X-ray photoelectron spectroscopy analysis, this intelligent switching wetting behavior under ultraviolet light irradiation was confirmed to have a high correlation with the change in surface chemical composition. When the electric stimulation was applied, the wettability switch was caused by the redistribution of charge and electric dipole along the liquid–solid interface. 

The start-up process is important for ensuring the end quality of slot coating products. This study uses ANSYS Fluent to explore the start-up process of slot coating with Carreau-type non-Newtonian fluid. The relationship between the pressure change in the coating bead at the slot outlet and the stabilization process of the coating bead is analyzed, and the effects of the downstream die lip angle and downstream die lip length on the size of the coating bead are discussed. The simulation results show that the pressure at the slot outlet directly affects the stabilization of the coating bead, and accelerating the coating bead stabilization pressure can accelerate the start-up process. When other parameters remain unchanged, reducing the downstream die lip angle or length can reduce the size of the coating bead, thereby accelerating the start-up process.

Surfaces that combine low-toxicity antifouling effects with fouling-release properties are an intriguing possibility for developing effective measures against marine biofouling. This study field tested siloxane-based fouling-release surfaces enhanced by adding biodegradable surfactants. Two different surfactants were added to a standard polydimethylsiloxane (PDMS) surface, as well as to PDMS soaked in silicone oil, and compared to controls without surfactant augmentation. Antifouling and fouling-release performance was assessed over 11 to 13 weeks against the most prominent fouling species at three locations in Cape Breton, Nova Scotia, Canada. Using nonlinear mixed effect analysis, surfactants were found to have little impact on the progression of biofouling on PDMS without silicone oil in all three sites and had no additional impact on the progression of biofouling on PDMS augmented with silicone oil. (Silicone oil was found to delay biofouling in PDMS without other additives.) Given the known toxicity of some surfactants to invertebrate larvae, future efforts should consider either higher concentrations or alternative varieties for incorporation into fouling-release surfaces.

Antimicrobial resistance has proven to be an existential threat that endangers the health of human beings. The ease of accessing conventional antibiotics, and their unlimited and unregulated use and often misuse is seen to be a contributing factor to the rise in the resistance of microbes toward medications. The overuse of these medications in the agricultural sector also adds to the rising burden of antibiotic resistance. In line with efforts to counter the threat of antimicrobial resistance and the menace of hospital acquired infections developing antimicrobial surface coatings that can eliminate microbes that get deposited on those coatings is essential. This review aims to bring an understanding of antimicrobial resistance mechanisms, the preparation and mode of action and the future perspective of the antimicrobial surface coatings.