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26 pages, 11891 KiB

Open AccessEditor’s ChoiceArticle

The Electrodeposition of Derivatives of Pyrrole and Thiophene on Brass Alloy in the Presence of Dodecane-1-Sulfonic Acid Sodium Salt in Acidic Medium and Its Anti-Corrosive Properties

by Florina Branzoi and Simona Petrescu

Coatings 2023, 13(5), 953; https://doi.org/10.3390/coatings13050953 - 19 May 2023

Cited by 1 | Viewed by 1653

Abstract

In this paper, potentiostatic and galvanostatic deposition (electrochemical deposition) processes have been used for the obtained of a new composite polymer: N-methylpyrrole-sodium 1-dodecanesulfonate/poly 2-methylthiophene (PNMPY-1SSD/P2MT) coatings over brass electrode for corrosion protection. The sodium 1-dodecanesulfonate as a dopant ion employed in the electropolymerization [...] Read more.

In this paper, potentiostatic and galvanostatic deposition (electrochemical deposition) processes have been used for the obtained of a new composite polymer: N-methylpyrrole-sodium 1-dodecanesulfonate/poly 2-methylthiophene (PNMPY-1SSD/P2MT) coatings over brass electrode for corrosion protection. The sodium 1-dodecanesulfonate as a dopant ion employed in the electropolymerization procedure can have a meaningful effect on the anti-corrosion protection of the composite polymeric film by stopping the penetration of corrosive ions. The composite coatings have been characterized by cyclic voltammetry, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) procedures. The anti-corrosion performance of PNMPY-1SSD/P2MT coated brass has been investigated by potentiostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) practices in 0.5 M H₂SO₄ medium. The corrosion assessment of PNMPY-1SSD/P2MT coated brass was noticed to be ~9 times diminished than of uncoated brass, and the efficiency of these protective coatings of this coating is above 90%. The highest effectiveness is realized by the electrochemical deposition of PNMPY-1SSD/P2MT obtained at 1.1 V and 1.4 V potential applied and at 0.5 mA/cm² and 1 mA/cm² current densities applied in molar ratio 5:3. The outcomes of the corrosion tests denoted that PNMPY-1SSD/P2MT coatings assure good anti-corrosion protection of brass in corrosive media. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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18 pages, 4956 KiB

Open AccessEditor’s ChoiceArticle

Migration of TiO₂ from PET/TiO₂ Composite Films Used for Polymer-Laminated Steel Cans in Acidic Solution

by Jingying Cui, Jinyang Chen, Jie Gu, Xiaomin Hong, Menghan Hong, Zheying Wu and Yu Hu

Coatings 2023, 13(5), 887; https://doi.org/10.3390/coatings13050887 - 8 May 2023

Cited by 2 | Viewed by 2029

Abstract

Nano-TiO₂ is widely used as a commercial food contact material (FCM), which poses potential risks to food. Therefore, the migration of TiO₂ is crucial for the safety of FCM. Since PET/TiO₂ composite films are food contact layers used for producing [...] Read more.

Nano-TiO₂ is widely used as a commercial food contact material (FCM), which poses potential risks to food. Therefore, the migration of TiO₂ is crucial for the safety of FCM. Since PET/TiO₂ composite films are food contact layers used for producing polymer-laminated steel cans and the majority of beverages contained in cans are acidic, it is necessary to study the migration of TiO₂ from PET/TiO₂ composite films in acidic solutions. The migration of TiO₂ in 4% (v/v) acetic acid was studied through the ICP-OES method. The corrosion process that occurred during the migration process was studied using electrochemical impedance spectroscopy (EIS). The morphology of Ti nanoparticles and films was measured by SEM, TEM, and dynamic light scattering (DLS) techniques. The results indicate that, at a temperature of 60 °C, the maximum migration concentration of TiO₂ is 0.32 mg/kg. The TiO₂ particles released during the migration process are unstable and tend to aggregate in the simulated material, with most of the Ti being present in the form of particles. Therefore, the migration of TiO₂ does not follow the Fick law of diffusion but rather conforms to the Weibull model based on the non-Fick law of diffusion. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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17 pages, 5449 KiB

Open AccessArticle

Effect of Calcination Temperature on the Structure, Crystallinity, and Photocatalytic Activity of Core-Shell SiO₂@TiO₂ and Mesoporous Hollow TiO₂ Composites

by Ning Fu, Hongjin Chen, Renhua Chen, Suying Ding and Xuechang Ren

Coatings 2023, 13(5), 852; https://doi.org/10.3390/coatings13050852 - 30 Apr 2023

Cited by 9 | Viewed by 2877

Abstract

TiO₂ and core–shell SiO₂@TiO₂ nanoparticles were synthesized by sol-gel process at different calcination temperatures. Mesoporous hollow TiO₂ composites were prepared by etching SiO₂ from SiO₂@TiO₂ nanoparticles with alkali solution. X-ray diffraction (XRD), Scanning electron [...] Read more.

TiO₂ and core–shell SiO₂@TiO₂ nanoparticles were synthesized by sol-gel process at different calcination temperatures. Mesoporous hollow TiO₂ composites were prepared by etching SiO₂ from SiO₂@TiO₂ nanoparticles with alkali solution. X-ray diffraction (XRD), Scanning electron microscope (SEM),Transmission electron microscope (TEM), and N₂ adsorption–desorption isotherms, and Roman and Diffuse reflectance spectroscopy (DRS) were employed to characterize the synthesized materials. The effects of different calcination temperatures on the morphology, crystallinity, phase composition, and photocatalytic activity of the prepared materials were investigated in detail. It was found that the calcination temperature altered the phase structure, crystallinity, morphology, specific surface area, and porous structure. Additionally, it was verified that SiO₂ could inhibit the transfer of TiO₂ from anatase phase to rutile phase under high temperature calcination (850 °C). The hollow TiO₂ calcined at 850 °C showed the highest photocatalytic efficiency of 97.5% for phenol degradation under UV irradiation. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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12 pages, 5797 KiB

Open AccessCommunication

Fabrication of Modified Polyurethane Sponge with Excellent Flame Retardant and the Modification Mechanism

by Hang Li, Chen-Yang Zhang, Ya-Ling Yu, Chang-Jin Liang, Guang-Ming Yuan, Huan Yang, Yun-Ying Wu and Shao-Min Lin

Coatings 2023, 13(4), 807; https://doi.org/10.3390/coatings13040807 - 21 Apr 2023

Cited by 3 | Viewed by 1976

Abstract

Research on polyurethane sponge (PUS), a widely used polymer material, and its flame-retardant performance is of great significance. In this study, PUS was modified to prepare a highly efficient flame-retardant composite using a soaking method. The PUS nearly vanished at 11 s after [...] Read more.

Research on polyurethane sponge (PUS), a widely used polymer material, and its flame-retardant performance is of great significance. In this study, PUS was modified to prepare a highly efficient flame-retardant composite using a soaking method. The PUS nearly vanished at 11 s after ignition, and the solid residue rate of the PUS was 5.65 wt% at 750 °C. The net structure, composed of nano SiO₂, was maintained in the modified PUS at 750 °C, and the solid residue rate was 69.23%. The maximum HRR of the PUS decreased from 617 W/g to 40 W/g and the THR of the sample reduced from 33 kJ/g to 9 kJ/g after modification. The results suggested that the modified PUS gained excellent flame-retardant performance. The flame-retardant layer in the modified PUS was amorphous. The surface of the modified PUS was rich in Si, O, and C elements and lacked a N element, suggesting that inorganic flame retardants were abundant on the surface layer of the modified PUS. The Si-O-C vibration and Si-O-Si stretching in the modified PUS indicates that the organic–inorganic hybrid structure formed on the PUS surface, which could be attributed to the polymerization and condensation of the silica precursor. Thus, the modified PUS provided an excellent flame-retardant layer. The results are of interest for producing efficient flame-retardant PUS using a simple method. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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12 pages, 3884 KiB

Open AccessArticle

The Effects of Urea and Caprolactam on the Diffusion Behavior of Water in Polyvinyl Alcohol (PVA): A Molecular Dynamics Simulation Study

by Fei Ni, Sen Zhang, Yuefei Pan, Shubo Xu, Wei Zheng and Xinzhi Hu

Coatings 2023, 13(4), 762; https://doi.org/10.3390/coatings13040762 - 12 Apr 2023

Cited by 1 | Viewed by 1926

Abstract

The effects of compound plasticizer urea/caprolactam (UC) on the diffusion behavior of water in mixtures with poly(vinyl alcohol) (PVA) were studied using a Molecular Dynamics (MD) simulation method. Five simulation models of PVA composites with different plasticizer contents were constructed to investigate the [...] Read more.

The effects of compound plasticizer urea/caprolactam (UC) on the diffusion behavior of water in mixtures with poly(vinyl alcohol) (PVA) were studied using a Molecular Dynamics (MD) simulation method. Five simulation models of PVA composites with different plasticizer contents were constructed to investigate the variation of the intermolecular interaction as well as the diffusion behavior of water molecules. Results showed that the predominant interaction between the functional groups of UC and PVA consisted of hydrogen bonds. As the plasticizer content increased, diffusion coefficients of water in PVA systems increased due to the comparably weak diffusion resistance. It was also found that the rotation of the PVA chains and the small molecules became faster with increasing UC content, and the relaxation time became shorter. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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19 pages, 5421 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Curing Temperature and Thickness of Polybutyl Methacrylate Siloxane Coatings on the Corrosion Protection of Structural Steel S355

by Damir Hamulić, Gregor Medoš, Dorota Korte, Peter Rodič and Ingrid Milošev

Coatings 2023, 13(4), 675; https://doi.org/10.3390/coatings13040675 - 26 Mar 2023

Cited by 5 | Viewed by 2307

Abstract

This study aimed to determine the effects of coating thickness and curing temperature on the properties of a polybutyl methacrylate-siloxane coating deposited on structural steel S355. First, the thermal properties of the sol as a function of temperature were investigated using thermogravimetric analysis [...] Read more.

This study aimed to determine the effects of coating thickness and curing temperature on the properties of a polybutyl methacrylate-siloxane coating deposited on structural steel S355. First, the thermal properties of the sol as a function of temperature were investigated using thermogravimetric analysis coupled with mass spectrometry and differential scanning calorimetry. After coating deposition on structural steel S355 using a dip-coating process, the coating composition and porosity were evaluated using Fourier transform infrared spectroscopy and photothermal beam deflection spectroscopy. In the second part, coating thickness, topography, and corrosion properties were studied as functions of withdrawal rate during deposition. The corrosion properties of variously prepared coatings were evaluated using electrochemical impedance measurements in 3.5 wt.% NaCl and salt spray testing according to the ASTM B117 standard. An elevated curing temperature (at 150 °C) of the polybutyl methacrylate siloxane sol-gel coating impairs greater crosslinking and lower porosity, while the optimal thickness of 4 μm is achieved with the appropriate withdrawal rate to obtain a homogeneous, defect-free surface. Under these optimal conditions, the protection of structural steel against corrosion in a chloride environment lasting for more than 6 months can be achieved. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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13 pages, 5586 KiB

Open AccessArticle

Laminated Cyclic Olefin Copolymer Foil by Pulsed Laser Deposition

by Mariapompea Cutroneo, Lorenzo Torrisi, Letteria Silipigni, Vladimir Havranek, Anna Mackova, Petr Malinsky, Romana Miksova, Jan Maly, Marcel Stofik, Petr Aubrecht, Dominik Fajstavr and Petr Slepicka

Coatings 2023, 13(3), 596; https://doi.org/10.3390/coatings13030596 - 10 Mar 2023

Cited by 4 | Viewed by 2359

Abstract

A cyclic olefin copolymer (COC) is a thermoplastic polymer endowed with glass-like optical transparency, unique biocompatibility, low autofluorescence, good chemical stability, and excellent water vapor barriers. COC is a promising new material for optics, medical devices, nanotechnology, and microelectronics. The applicability of the [...] Read more.

A cyclic olefin copolymer (COC) is a thermoplastic polymer endowed with glass-like optical transparency, unique biocompatibility, low autofluorescence, good chemical stability, and excellent water vapor barriers. COC is a promising new material for optics, medical devices, nanotechnology, and microelectronics. The applicability of the COC depends on its modification through different techniques from plasma treatment to lithography. Presently, pulsed laser deposition (PLD) is employed to deposit an aluminum thin film on selected areas of the COC surface. The study of the wettability, morphology, composition, and optical characteristics of both pristine and modified COC has been evaluated by scanning electron and atomic force microscopies, the sessile drop method, and UV/ViS optical spectroscopy. The prospective recycling of the COC deposited by PLD is proposed. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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14 pages, 7700 KiB

Open AccessArticle

Fabric Electrode Monitoring of Dynamic and Static ECG Signal and Comfort Performance

by Jinli Zhou, Yazhou Zhang, Hongying Yang, Qingxia Liu, Ming Wang, Fan Xiong, Dongyi Chen and Lixin Du

Coatings 2023, 13(2), 289; https://doi.org/10.3390/coatings13020289 - 27 Jan 2023

Cited by 7 | Viewed by 2734

Abstract

To monitor dynamic ECG for a long time, fabric electrodes must have excellent comfort and electrical properties. In addition, the quality of the collected ECG should be as free as possible from interference by motion artifacts due to dry skin and body movement. [...] Read more.

To monitor dynamic ECG for a long time, fabric electrodes must have excellent comfort and electrical properties. In addition, the quality of the collected ECG should be as free as possible from interference by motion artifacts due to dry skin and body movement. This study explores the comfort of four different materials and structures of silver-plated fabric electrodes, analyzing the acquisition effect of ECG signals under dynamic and static conditions. To obtain fabric electrodes with good comfort levels and stable ECG signal monitoring under dynamic and static conditions, four kinds of electroless silver-plated conductive fabrics were selected and assembled into fabric electrodes. Permeability, electrochemical impedance spectrum, static opening voltage, and dynamic static electrocardiogram were tested and evaluated for each of the four fabric electrodes; additionally, the comfort of the four fabric electrodes and the mass of ECG monitored under dynamic and static conditions were assessed. The results showed that the highly hygroscopic knitted fabric electrode showed better comfort than the other three samples. The electrochemical impedance spectrum curve of the highly hygroscopic knitted fabric electrode was relatively smooth and stable, and it had lower impedance than the other electrodes; moreover, the static open-circuit voltage changed more stably with the increase of processing time compared to the other samples. The four kinds of fabric electrodes all collected clear and stable ECG in the resting state. However, in dynamic conditions, only the highly hygroscopic knitted fabric electrodes collected stable ECG under the conditions of seven daily life actions, clearly distinguishing between the P-wave, QRS wave group, and T-wave. The knitted fabric electrode has a high correlation with the ECG measured by a disposable gel electrode, meeting the standards needed to monitor ECG during the human body’s daily activities. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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16 pages, 2474 KiB

Open AccessFeature PaperArticle

Application of Vegetable Oil-Based Monomers in the Synthesis of Acrylic Latexes via Emulsion Polymerization

by Martin Kolář, Jana Machotová, Martin Hájek, Jan Honzíček, Tomáš Hájek and Štěpán Podzimek

Coatings 2023, 13(2), 262; https://doi.org/10.3390/coatings13020262 - 22 Jan 2023

Cited by 7 | Viewed by 3406

Abstract

In this work, two bio-based raw materials, rapeseed oil and technical-grade oleic acid, were modified to yield acrylated monomers. Polymeric latexes designed for coating applications were synthesized using emulsion polymerization. Methyl methacrylate and butyl acrylate were copolymerized with various ratios of the acrylated [...] Read more.

In this work, two bio-based raw materials, rapeseed oil and technical-grade oleic acid, were modified to yield acrylated monomers. Polymeric latexes designed for coating applications were synthesized using emulsion polymerization. Methyl methacrylate and butyl acrylate were copolymerized with various ratios of the acrylated bio-based monomers (0–20 wt.% in the monomer mixture). The polymerization with high monomer conversion and low coagulum content was successfully performed up to the content of 15 wt.% of the bio-based monomers, leading to long-term stable latexes. The asymmetric flow field flow fractionation coupled with a multi-angle light scattering detector was used to describe the molar mass distribution of the synthesized copolymers. Ultra-high molar mass fractions were detected in copolymers comprising the bio-based monomers due to the presence of multi-acrylated bio-based ingredients originating from linoleic and linolenic fatty acids. This phenomenon became more pronounced for the rapeseed oil-originated monomer. The prepared latexes comprising copolymerized bio-based monomers showed comparable or even better coating performance in terms of gloss and water resistance in comparison with the reference acrylic coating, which makes the acrylated vegetable oil-based monomers attractive for the manufacturing of sustainable water-borne materials in the coating industry. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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16 pages, 14096 KiB

Open AccessArticle

Fabrication of Silver-Doped UiO-66-NH₂ and Characterization of Antibacterial Materials

by Feng Tian, Rengui Weng, Xin Huang, Guohong Chen and Zhitao Huang

Coatings 2022, 12(12), 1939; https://doi.org/10.3390/coatings12121939 - 9 Dec 2022

Cited by 10 | Viewed by 2862

Abstract

Metal-organic frameworks (MOFs) are highly crystalline inorganic-organic complexes formed from metal ions or metal clusters and multi-toothed organic ligands. MOFs have great potential for use in antibacterial materials in the biological, environmental, and food antimicrobial fields. They can act as a reservoir of [...] Read more.

Metal-organic frameworks (MOFs) are highly crystalline inorganic-organic complexes formed from metal ions or metal clusters and multi-toothed organic ligands. MOFs have great potential for use in antibacterial materials in the biological, environmental, and food antimicrobial fields. They can act as a reservoir of metal ions, releasing them gradually and leading to a sustained antibacterial effect analogous to that proposed for metal oxide nanoparticles (NPs). Herein, UiO-66-NH₂ as a type of MOF was first prepared by a facile solvothermal method and then loaded with Ag NPs to form a Ag/UiO-66-NH₂ composite and the different materials were synthesized by controlling silver doping amount, which are then applied to an antibacterial test. Works on the synthesis of Ag/UiO-66-NH₂ and its antibacterial test were not reported before. The synthesized materials were characterized using the field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. The antibacterial activity of the Ag/UiO-66-NH₂ was then assessed against E. coli (gram-negative bacteria) and Staphylococcus aureus (gram-positive bacteria), using the inhibition zone (ZIO) method and optical density (OD) method. The obtained results have shown that the introduction of Ag does not interfere with the crystallization of UiO-66-NH₂. The FT-IR spectral profiles recorded for the UiO-66-NH₂ samples fabricated under conditions of varying silver ion doping levels are similar to those recorded for UiO-66-NH₂. The thermal stability of UiO-66-NH₂ containing varying amounts of silver ions was lower than the thermal stability of UiO-66-NH₂. However, under these conditions, the specific surface area and pore volume increased. The antibacterial performance of UiO-66-NH₂ improved significantly following the process of silver ion doping. The best antibacterial performance was observed when the silver ion content was 4 wt.%. Overall, we synthesized a new nanocomposite material with broad-spectrum bacterial sterilization, which was easy to manufacture. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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13 pages, 16713 KiB

Open AccessArticle

In Situ Growth of PbS Nanoparticles without Organic Linker on ZnO Nanostructures via Successive Ionic Layer Adsorption and Reaction (SILAR)

by Basma ElZein, Mutalifu Abulikemu, Ahmad S. Barham, Alia Al-Kilani, Mohammed I. Alkhatab, Samir M. Hamdan, Elhadj Dogheche and Ghassan E. Jabbour

Coatings 2022, 12(10), 1486; https://doi.org/10.3390/coatings12101486 - 6 Oct 2022

Cited by 3 | Viewed by 2078

Abstract

The process of effective solar energy harvesting and conversion requires efficient photon absorption, followed by charge generation and separation, then electron transfer. Nanostructured materials have been considered as potential building blocks for the development of future generations of solar cells. Much attention has [...] Read more.

The process of effective solar energy harvesting and conversion requires efficient photon absorption, followed by charge generation and separation, then electron transfer. Nanostructured materials have been considered as potential building blocks for the development of future generations of solar cells. Much attention has been given to wide-bandgap semiconductor nanowires, combined and sensitized with low-bandgap semiconductors effectively attached to the nanowires for low-cost and highly efficient solar cells. Here, the in situ growth of lead sulfide (PbS) nanoparticles on the surface of zinc oxide (ZnO) nanowires grown by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique is presented for different numbers of cycles. The morphology and structure of PbS nanoparticles are confirmed by Scanning Electron Microscopy (SEM), revealing the decoration of the nanowires with the PbS nanoparticles, Transmission Electron Microscopy (TEM) and HR-TEM, showing the tight attachment of PbS nanoparticles on the surface of the ZnO nanowires. The Selected Area Electron Diffraction (SAED) confirms the crystallization of the PbS. Photoluminescence spectra show a broad and more intense deep-level emission band. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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28 pages, 2335 KiB

Open AccessArticle

Influence of Metal Oxide Nanoparticles as Antimicrobial Additives Embedded in Waterborne Coating Binders Based on Self-Crosslinking Acrylic Latex

by Denisa Steinerová, Andréa Kalendová, Jana Machotová, Petr Knotek, Petr Humpolíček, Jan Vajdák, Stanislav Slang, Anna Krejčová, Ludvík Beneš and Felipe Wolff-Fabris

Coatings 2022, 12(10), 1445; https://doi.org/10.3390/coatings12101445 - 30 Sep 2022

Cited by 10 | Viewed by 2557

Abstract

This article deals with the simple preparation of environmentally friendly acrylic latex binders, which are functionalized with nanoparticles of metal oxides, namely MgO, ZnO, La₂O₃ and combinations of MgO and ZnO, serving as functional components to achieve antimicrobial properties, but [...] Read more.

This article deals with the simple preparation of environmentally friendly acrylic latex binders, which are functionalized with nanoparticles of metal oxides, namely MgO, ZnO, La₂O₃ and combinations of MgO and ZnO, serving as functional components to achieve antimicrobial properties, but also to improve physical–mechanical properties and chemical resilience. The incorporation of uncoated powder nanoparticles was performed during the synthesis, using the two-stage semi-continuous emulsion radical polymerization technique, to obtain latexes containing 0.5%–1.3% nanoparticles relative to the polymer content. Changes in latex performance due to nanoparticles were compared from the point of view of the type and concentration of metal oxide nanoparticles in latex. The results of the tests showed that all types of nanoparticles showed very promising properties, while with increasing concentration of nanoparticles there was an improvement in properties. The nanoparticles in latex provided interfacially crosslinked transparent smooth coating films with high gloss and good physical–mechanical properties. Latexes containing the highest concentration of nanoparticles provided coatings with significant antimicrobial activity against all tested bacterial and fungal strains, but also in-can preservative stability of liquid latex. Furthermore, the coatings were resistant to solvents, and in addition, latexes with MgO nanoparticles showed a significant decrease in the minimum film-forming temperature, and latex with a concentration of about 1.3% MgO did not show any flash corrosion under the coating film cast on a steel substrate. The latexes containing MgO and La₂O₃ nanoparticles provided coatings that were very resistant to water bleaching. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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18 pages, 8133 KiB

Open AccessArticle

Preparation of ZnFe₂O₄@TiO₂ Novel Core-Shell Photocatalyst by Ultrasonic Method and Its Photocatalytic Degradation Activity

by Renhua Chen, Suying Ding, Bo Wang and Xuechang Ren

Coatings 2022, 12(10), 1407; https://doi.org/10.3390/coatings12101407 - 27 Sep 2022

Cited by 17 | Viewed by 2413

Abstract

ZnFe₂O₄ microspheres were prepared by solvothermal method, and a novel ZnFe₂O₄@TiO₂ core-shell composite photocatalyst was prepared by ultrasonic (denoted as ZT-x) and mechanical stirring (denoted as ZTM-1.2). The morphology, structure, magnetic, and optoelectronic properties of [...] Read more.

ZnFe₂O₄ microspheres were prepared by solvothermal method, and a novel ZnFe₂O₄@TiO₂ core-shell composite photocatalyst was prepared by ultrasonic (denoted as ZT-x) and mechanical stirring (denoted as ZTM-1.2). The morphology, structure, magnetic, and optoelectronic properties of the catalyst were investigated comprehensively, and the degradation performance of the catalyst was explored through the photocatalytic degradation of Rhodamine B (RhB) under UV light. The concentration of RhB was 10 mg/L, and the catalyst concentration was 0.3 g/L. ZT-1.2 showed the best photocatalytic degradation activity, and the degradation rate of RhB reached 97.3% within 60 min. The degradation ability of the catalyst was further evaluated by Methylene blue (MB), Methyl orange (MO), Phenol, and Ofloxacin (OFX). ZT-1.2 also exhibited excellent stability. The improved catalyst degradation performance was attributed to constructing a Z-type heterojunction. Moreover, the low-efficiency degradation of ZTM-1.2 was caused by catalyst agglomeration and low TiO₂ loading, confirming the superiority of the ultrasonic method and providing a new method for the preparation of magnetically recoverable TiO₂-based core-shell photocatalyst. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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18 pages, 15637 KiB

Open AccessArticle

Effect of Fluorinated Comonomer, Polymerizable Emulsifier, and Crosslinking on Water Resistance of Latex Coatings

by Jana Machotova, Petr Knotek, Eva Cernoskova, Roman Svoboda, Lucie Zarybnicka, Miroslav Kohl and Andrea Kalendova

Coatings 2022, 12(8), 1150; https://doi.org/10.3390/coatings12081150 - 9 Aug 2022

Cited by 10 | Viewed by 3495

Abstract

Common latex coatings suffer from poor water resistance, which often limits their practical application. This paper reports on the preparation of polyacrylate latexes using various approaches to tune the water resistance, wettability, and surface properties of their coating films. The mutual effects of [...] Read more.

Common latex coatings suffer from poor water resistance, which often limits their practical application. This paper reports on the preparation of polyacrylate latexes using various approaches to tune the water resistance, wettability, and surface properties of their coating films. The mutual effects of fluorinated monomer copolymerization, emulsifier type (polymerizable and general), and intra- or interparticle covalent crosslinking (due to allyl methacrylate copolymerization and a keto-hydrazide reaction, respectively) were studied. The polyacrylate latexes were synthesized through a two-step semicontinuous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate, butyl acrylate, methyl methacrylate, and methacrylic acid as the basic monomers. The fluorinated monomer was incorporated into the second-step polymer (at a content of 30 wt.% based on the second-step monomer feeds). The water resistance, wettability, and surface properties of the coating films were evaluated with focus on the water absorption, water whitening, water contact angle, and surface topography using atomic force microscopy. It was found that highly water-resistant and hydrophobic coatings that possessed a self-healing ability were prepared, provided that the polymerizable emulsifier and the fluorinated monomer were involved in the latex synthesis, along with the intra- and interparticle covalent crosslinking. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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24 pages, 6408 KiB

Open AccessArticle

Corrosion Protection Efficacy of the Electrodeposit of Poly (N-Methyl Pyrrole-Tween20/3-Methylthiophene) Coatings on Carbon Steel in Acid Medium

by Florina Branzoi, Marius Alexandru Mihai and Simona Petrescu

Coatings 2022, 12(8), 1062; https://doi.org/10.3390/coatings12081062 - 27 Jul 2022

Cited by 4 | Viewed by 1899

Abstract

In this study, poly(N-methylpyrrole-Tween20/3-methylthiophene) coatings were electrodeposited on carbon steel type OLC 45 by electrochemical techniques in oxalic acid solution. Surfactant Tween 20 as a dopant ion employed during electropolymerization can have an important influence on the corrosion protection of this coating by [...] Read more.

In this study, poly(N-methylpyrrole-Tween20/3-methylthiophene) coatings were electrodeposited on carbon steel type OLC 45 by electrochemical techniques in oxalic acid solution. Surfactant Tween 20 as a dopant ion employed during electropolymerization can have an important influence on the corrosion protection of this coating by obstructing the penetration of aggressive sulfate ions. The new composite coatings have been analyzed electrochemically, spectroscopically and morphologically by cyclic voltammetry, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) methods. Corrosion protection consideration of PNMPY-TW20/P3MT-coated OLC 45 has been analyzed by potentiostatic and potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy (EIS) measurements in 0.5 M H₂SO₄ medium. The corrosion rate of PNMPY-TW20/P3MT-coated OLC 45 has been indicated to be ~10 times reduced compared to uncoated OL 45, and the corrosion protection efficiency of the coating is above 90%. The greatest efficacy is achieved by PNMPY-TW20/P3MT composite by electrodeposition at 5 mA/cm² and 3 mA/cm² current densities applied and at 1200 mV potential applied in 5:1 and 3:5 molar ratios. The PNMPY-TW20/P3MT coating realized by the galvanostatic method exhibited a non-damaging surveying after 96 h of immersion in the aggressive medium, further verifying its excellent protection capacity. The consequences of the corrosion experiments clearly divulged that PNMPY-TW20/P3MT coatings ensure a very good anticorrosion protection of OLC 45 in aggressive medium. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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13 pages, 10943 KiB

Open AccessArticle

Electrodeposition, Characterization, and Corrosion Behavior of CoCrFeMnNi High-Entropy Alloy Thin Films

by Ana-Maria Julieta Popescu, Florina Branzoi, Ionut Constantin, Mihai Anastasescu, Marian Burada, Dumitru Mitrică, Ioana Anasiei, Mihai-Tudor Olaru and Virgil Constantin

Coatings 2021, 11(11), 1367; https://doi.org/10.3390/coatings11111367 - 8 Nov 2021

Cited by 33 | Viewed by 4898

Abstract

Potentiostatic electrodeposition was used to obtain CoCrFeMnNi high-entropy alloy (HEA) thin films on copper substrate. An electrolyte based on a DMSO (dimethyl sulfoxide)-CH₃CN (acetonitrile) organic compound was used for the HEA deposition. The microstructure of the high-entropy deposits before and after [...] Read more.

Potentiostatic electrodeposition was used to obtain CoCrFeMnNi high-entropy alloy (HEA) thin films on copper substrate. An electrolyte based on a DMSO (dimethyl sulfoxide)-CH₃CN (acetonitrile) organic compound was used for the HEA deposition. The microstructure of the high-entropy deposits before and after corrosion in artificial seawater was investigated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) investigation. SEM analysis revealed that compact and uniform film consists of compact and uniform 50 nm–5 μm particles that form the HEA films. The successful co-deposition of all five elements was highlighted by the energy dispersive spectrometry investigation (EDS). Electrochemical measurements carried out in an aerated artificial seawater solution under ambient conditions demonstrated the promising potential for application in the field of anti-corrosion protection, due to the protective behavior of the HEA thin films. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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22 pages, 3448 KiB

Open AccessArticle

Evaluation of Corrosion Protection Performance of New Polymer Composite Coatings on Carbon Steel in Acid Medium by Electrodeposition Methods

by Florina Branzoi, Adriana Băran and Simona Petrescu

Coatings 2021, 11(8), 903; https://doi.org/10.3390/coatings11080903 - 28 Jul 2021

Cited by 5 | Viewed by 2424

Abstract

In this research, electrodeposition procedure was utilized for the synthesis of a new composite polymer: N-methylpyrrole–Triton–X100/N, N,N-diethylaniline (NMPY-TRX100/NNDEA) used as a coating on carbon steel type OL 37 electrode for corrosion protection. The surfactant Triton–X100, a dopant ion utilized [...] Read more.

In this research, electrodeposition procedure was utilized for the synthesis of a new composite polymer: N-methylpyrrole–Triton–X100/N, N,N-diethylaniline (NMPY-TRX100/NNDEA) used as a coating on carbon steel type OL 37 electrode for corrosion protection. The surfactant Triton–X100, a dopant ion utilized throughout the process of electropolymerization, had a significant impact on the corrosion protection of this composite by impeding the penetration of corrosive ions. PNMPY-TRX100/PNNDEA coatings were successfully realized on the OL37 substrate by a galvanostatic method of synthesis using the solutions 0.1 M NNDEA, 0.1 M MPY, 0.03 M TRX-100, and 0.3 M H₂C₂O₄, at varied current densities (3 mA/cm², 5 mA/cm² and 8 mA/cm²) in different molar ratios (1:1, 1:5, 3:2 and 5:1). The deposition was performed for 20 and 30 min. The polymeric composite coatings were characterized electrochemically, spectroscopically, and morphologically by cyclic voltammetry, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. Corrosion protection performance of PNMPY-TRX100/PNNDEA-coated OL 37 was examined through potentiostatic and potentiodynamic polarization, open circuit potential measurements, and electrochemical impedance spectroscopy procedures in 0.5 M H₂SO₄ media. The corrosion rate of PNPMPY-TRX100/PNNDEA-coated OL 37 was denoted to be around nine times less than that of an uncoated electrode. The corrosion protection yield of the coating was more than 90%. The best effectiveness was realized for PNMPY-TRX-100/PNNDEA by electrodeposition at 5 mA/cm² current density applied in molar ratios of 5:1 and 3:2, and at 8 mA/cm² current densities applied in molar ratio 5:1. The outcomes of the corrosion experiments revealed that PNMPY-TRX-100/PNNDEA coatings provide a good anticorrosion protection of OL 37 in corrosive solutions. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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21 pages, 3928 KiB

Open AccessReview

Self-Assembled Monolayer Coatings on Gold and Silica Surfaces for Antifouling Applications: A Review

by Yunsoo Choi, Hung-Vu Tran and T. Randall Lee

Coatings 2022, 12(10), 1462; https://doi.org/10.3390/coatings12101462 - 4 Oct 2022

Cited by 18 | Viewed by 5002

Abstract

The resistance of surfaces to biomaterial adsorption/adhesion is paramount for advancing marine and biomedical industries. A variety of approaches that involve bioinert materials have been developed to modify surfaces. Self-assembled monolayers (SAMs) are powerful platforms in which the surface composition is easily fabricated [...] Read more.

The resistance of surfaces to biomaterial adsorption/adhesion is paramount for advancing marine and biomedical industries. A variety of approaches that involve bioinert materials have been developed to modify surfaces. Self-assembled monolayers (SAMs) are powerful platforms in which the surface composition is easily fabricated and a well-defined structure is provided; thus, the molecular-level interaction between biomolecules/biofoulants and the surface can be understood. In this review, we describe a wide variety of SAM structures on gold and silica surfaces for antifouling applications and the corresponding mechanism of nonfouling surfaces. Our analysis divides the surface properties of films into the following types: (1) hydrophilic, (2) hydrophobic, and (3) amphiphilic films. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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