Materials

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15 pages, 7712 KiB

Open AccessArticle

Electrophoretic Co-deposition of Polyetheretherketone and Graphite Particles: Microstructure, Electrochemical Corrosion Resistance, and Coating Adhesion to a Titanium Alloy

by Aleksandra Fiołek, Sławomir Zimowski, Agnieszka Kopia, Alicja Łukaszczyk and Tomasz Moskalewicz

Materials 2020, 13(15), 3251; https://doi.org/10.3390/ma13153251 - 22 Jul 2020

Cited by 12 | Viewed by 2237

Abstract

The present study explores the possibilities of fabricating a graphite/polyetheretherketone (PEEK) composite coating on a Ti-6Al-4V titanium alloy through duplex treatment consisting of electrophoretic deposition (EPD) and heat treatment. It has been found that the electrophoretic co-deposition of graphite and PEEK microparticles can [...] Read more.

The present study explores the possibilities of fabricating a graphite/polyetheretherketone (PEEK) composite coating on a Ti-6Al-4V titanium alloy through duplex treatment consisting of electrophoretic deposition (EPD) and heat treatment. It has been found that the electrophoretic co-deposition of graphite and PEEK microparticles can be performed from environmentally-friendly pure ethanolic suspensions. Zeta potential measurements and a study of the interaction between both particle types with the use of transmission electron microscopy allowed potential mechanisms of particle co-deposition to be indicated. Microstructure characterization was performed on macro-, micro- and nanoscale using visible light microscopy, X-ray diffractometry and electron microscopy. This allowed the coating homogeneity and distribution of graphite particles in the polymer matrix to be described. Graphite particles in the form of graphene nanosheet packages were relatively evenly distributed in the coating matrix and oriented parallel to the coating surface. The heat-treated coatings showed high scratch resistance and no adhesive type destruction was observed, but they were highly susceptible to deformation. The corrosion measurements were performed with use of electrochemical techniques like open circuit potential and linear sweep voltamperometry. The coated alloy indicated better electrochemical corrosion resistance compared with the uncoated alloy. This work showed the high versatility of the electrophoretic co-deposition of graphite and PEEK particles, which combined with post-EPD heat treatment allows composite coatings to be fabricated with controlled distribution of graphite particles. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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12 pages, 1975 KiB

Open AccessArticle

The Luminescence of 1,8-Diazafluoren-9-One/Titanium Dioxide Composite Thin Films for Optical Application

by Aneta Lewkowicz, Robert Bogdanowicz, Piotr Bojarski, Mattia Pierpaoli, Ignacy Gryczyński, Anna Synak, Michał Mońka, Jakub Karczewski, Wiktoria Struck-Lewicka, Renata Wawrzyniak and Michał J. Markuszewski

Materials 2020, 13(13), 3014; https://doi.org/10.3390/ma13133014 - 06 Jul 2020

Cited by 3 | Viewed by 2490

Abstract

The investigation of innovative label-free α-amino acids detection methods represents a crucial step for the early diagnosis of several diseases. While 1,8-diazafluoren-9-one (DFO) is known in forensic application because of the fluorescent products by reacting with the amino acids present in the papillary [...] Read more.

The investigation of innovative label-free α-amino acids detection methods represents a crucial step for the early diagnosis of several diseases. While 1,8-diazafluoren-9-one (DFO) is known in forensic application because of the fluorescent products by reacting with the amino acids present in the papillary exudate, its application for diagnostic purposes has not been fully investigated. The stabilization of DFO over a transparent substrate allows its complexation with biomolecules for the detection of α-amino acids. In this study, DFO was immobilized into a titanium dioxide (TiO₂) matrix for the fluorescence detection of glycine, as a target α-amino acid (a potential marker of the urogenital tract cancers). The DFO/TiO₂ composite was characterized by atomic force microscopy, spectroscopic ellipsometry, fluorescence spectroscopy and fluorescence microscopy. The performed fluorescent studies indicate spectacular formation of aggregates at higher concentration. The measurements performed using various fluorescence and microscopic techniques together with the suitable analysis show that the aggregates are able to emit short-lived fluorescence. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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15 pages, 5550 KiB

Open AccessArticle

Preparation of UV-Curable Low Surface Energy Polyurethane Acrylate/Fluorinated Siloxane Resin Hybrid Coating with Enhanced Surface and Abrasion Resistance Properties

by Jianping Zhou, Chunfang Zhu, Hongbo Liang, Zhengyue Wang and Hailong Wang

Materials 2020, 13(6), 1388; https://doi.org/10.3390/ma13061388 - 19 Mar 2020

Cited by 10 | Viewed by 3382

Abstract

Low surface energy coatings have gained considerable attention due to their superior surface hydrophobic properties. However, their abrasion resistance and sustainability of surface hydrophobicity are still not very satisfactory and need to be improved. In this work, a series of utraviolet (UV)-curable fluorosiloxane [...] Read more.

Low surface energy coatings have gained considerable attention due to their superior surface hydrophobic properties. However, their abrasion resistance and sustainability of surface hydrophobicity are still not very satisfactory and need to be improved. In this work, a series of utraviolet (UV)-curable fluorosiloxane copolymers were synthesized and used as reactive additives to prepare polyurethane acrylate coatings with low surface energy. The effect of the addition of the fluorinated graft copolymers on the mechanical durability and surface hydrophobicity of the UV-cured hybrid films during the friction-annealing treatment cycles was investigated. The results show that introducing fluorosiloxane additives can greatly enhance surface hydrophobicity of the hybrid film. With addition of 2 wt.% fluorosiloxane copolymers, the water contact angle (WCA) value of the hybrid film was almost tripled compared to that of the pristine PU film, increasing from 58° to 144°. The hybrid film also showed enhanced abrasion resistance and could withstand up to about 60 times of friction under a pressure of 20 kPa. The microstructure formed in the annealed film was found to contribute much to achieve better surface hydrophobicity. The polyurethane acrylate/fluorinated siloxane resin hybrid film prepared in this study exhibits excellent potential for applications in the low surface energy field. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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11 pages, 2477 KiB

Open AccessArticle

Insertion of Iron Decorated Organic–Inorganic Cage-Like Polyhedral Oligomeric Silsesquioxanes between Clay Platelets by Langmuir Schaefer Deposition

by Jiquan Wu, Georgia Potsi, Regis Y. N. Gengler, Dimitrios Gournis and Petra Rudolf

Materials 2020, 13(1), 216; https://doi.org/10.3390/ma13010216 - 04 Jan 2020

Cited by 2 | Viewed by 2096

Abstract

Tuning the architecture of multilayer nanostructures by exploiting the properties of their constituents is a versatile way to develop multifunctional films. Herein, we report a bottom-up approach for the fabrication of highly ordered hybrid films consisting of dimethyldioctadecylammonium (DODA), iron decorated polyhedral oligomeric [...] Read more.

Tuning the architecture of multilayer nanostructures by exploiting the properties of their constituents is a versatile way to develop multifunctional films. Herein, we report a bottom-up approach for the fabrication of highly ordered hybrid films consisting of dimethyldioctadecylammonium (DODA), iron decorated polyhedral oligomeric silsesquioxanes (POSS), and montmorillonite clay platelets. Clay platelets provided the template where Fe/POSS moieties were grafted by the use of the surfactant. Driven by the iron ions present, DODA adopted a staggered arrangement, which is essential to realize the controllable layer-by-layer growth of the film. The elemental composition of the film was studied by X-ray photoelectron spectroscopy and X-ray reflectivity confirmed the existence of smooth interfaces between the different layers. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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16 pages, 4242 KiB

Open AccessArticle

Perfect Combination of LBL with Sol–Gel Film to Enhance the Anticorrosion Performance on Al Alloy under Simulated and Accelerated Corrosive Environment

by Xia Zhao, Shuai Yuan, Zuquan Jin, Binbin Zhang, Nazhen Liu, Shibo Chen, Shuan Liu, Xiaolin Sun and Jizhou Duan

Materials 2020, 13(1), 111; https://doi.org/10.3390/ma13010111 - 25 Dec 2019

Cited by 6 | Viewed by 2542

Abstract

Given their outstanding versatile properties, multilayered anticorrosion coatings have drawn great interest from researchers in the academic and engineering fields. However, the application of multilayered coatings is restricted by some limitations such as low interlayer compatibilities, the harsh preparation process, etc. This work [...] Read more.

Given their outstanding versatile properties, multilayered anticorrosion coatings have drawn great interest from researchers in the academic and engineering fields. However, the application of multilayered coatings is restricted by some limitations such as low interlayer compatibilities, the harsh preparation process, etc. This work introduced a composite film fabricated on a 2A12 aluminum alloy surface, including an anodic oxide film, a sol–gel film, and a layer-by-layer (LBL) self-assembling film from bottom to top. The microstructure and elemental characterization indicated that the finish of the coating with the LBL film resulted in a closely connected multilayered coating with a smoother surface. The anticorrosion performance was systematically evaluated in the simulated corrosive medium and neutral salt spray environment. The integrated coating with the LBL film presented an excellent anticorrosion ability with system impedance over 10⁸ Ω·cm² and a self-corrosion current density two orders of magnitude lower than that of the other coatings. After the acceleration test in a salt spray environment, the multilayered coatings could still show a good protective performance with almost no cracks and no penetration of chloride ions. It is believed that the as-constructed multilayered coating with high corrosive properties and a fine surface state will have promising applications in the field of anticorrosion engineering. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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12 pages, 4142 KiB

Open AccessArticle

Development of Marine Antifouling Epoxy Coating Enhanced with Clay Nanotubes

by Ye Fu, Wencai Wang, Liqun Zhang, Vladimir Vinokurov, Anna Stavitskaya and Yuri Lvov

Materials 2019, 12(24), 4195; https://doi.org/10.3390/ma12244195 - 13 Dec 2019

Cited by 25 | Viewed by 3604

Abstract

An antifouling epoxy resin doped with natural clay nanotubes that are loaded with biocide or silver allowed extended protection against the proliferation of marine microorganisms. Compared to the 2–3 months of protection with antifoulant dichlorooctylisothiazolone (DCOIT) directly admixed into epoxy resin, the DCOIT [...] Read more.

An antifouling epoxy resin doped with natural clay nanotubes that are loaded with biocide or silver allowed extended protection against the proliferation of marine microorganisms. Compared to the 2–3 months of protection with antifoulant dichlorooctylisothiazolone (DCOIT) directly admixed into epoxy resin, the DCOIT release time of the halloysite formulations was extended to 12 months by incorporating biocide-loaded nanoclay in the polymer matrix. The protective properties of the epoxy-halloysite nanocomposites showed much less adhesion and proliferation of marine bacteria Vibrio natriegens on the resin surface after a two-month exposure to seawater than the coating formulations directly doped with non-encapsulated DCOIT. The coating formulation protection efficiency was further confirmed by twelve-month shallow field tests in the South China Sea. Replacing 2 wt.% biocide in the traditional formula with DCOIT-loaded natural environmentally friendly halloysite clay drastically improved the antifouling properties of the epoxy coating, promising scalable applications in protective marine coating. The antifouling property of epoxy resin was enhanced with silver particles synthesized on halloysite nanotubes. A natural mixture of MnO particles and halloysite could also be used as a nonbiocide additive to marine coating. The short-term White Sea water test of epoxy coating with 5% of Ag-halloysite composite of MnO-halloysite natural mixture showed no visible fouling. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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15 pages, 4497 KiB

Open AccessFeature PaperArticle

Deposition Kinetics of Thin Silica-Like Coatings in a Large Plasma Reactor

by Žiga Gosar, Denis Đonlagić, Simon Pevec, Janez Kovač, Miran Mozetič, Gregor Primc, Alenka Vesel and Rok Zaplotnik

Materials 2019, 12(19), 3238; https://doi.org/10.3390/ma12193238 - 03 Oct 2019

Cited by 6 | Viewed by 2223

Abstract

An industrial size plasma reactor of 5 m³ volume was used to study the deposition of silica-like coatings by the plasma-enhanced chemical vapor deposition (PECVD) method. The plasma was sustained by an asymmetrical capacitively coupled radio-frequency discharge at a frequency of 40 [...] Read more.

An industrial size plasma reactor of 5 m³ volume was used to study the deposition of silica-like coatings by the plasma-enhanced chemical vapor deposition (PECVD) method. The plasma was sustained by an asymmetrical capacitively coupled radio-frequency discharge at a frequency of 40 kHz and power up to 7 kW. Hexamethyldisilioxane (HMDSO) was introduced continuously at different flows of up to 200 sccm upon pumping with a combination of roots and rotary pumps at an effective pumping speed between 25 and 70 L/s to enable suitable gas residence time in the plasma reactor. The deposition rate and ion density were measured continuously during the plasma process. Both parameters were almost perfectly constant with time, and the deposition rate increased linearly in the range of HMDSO flows from 25 to 160 sccm. The plasma density was of the order of 10¹⁴ m⁻³, indicating an extremely low ionization fraction which decreased with increasing flow from approximately 2 × 10⁻⁷ to 6 × 10⁻⁸. The correlations between the processing parameters and the properties of deposited films are drawn and discussed. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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10 pages, 3169 KiB

Open AccessCommunication

Enhanced Wear Performance of Cu-Carbon Nanotubes Composite Coatings Prepared by Jet Electrodeposition

by Dongdong Ning, Ao Zhang and Hui Wu

Materials 2019, 12(3), 392; https://doi.org/10.3390/ma12030392 - 27 Jan 2019

Cited by 18 | Viewed by 2741

Abstract

Cu-carbon nanotubes (CNTs) composite coatings with high CNT content and uniformly distributed CNTs were successfully prepared via jet electrodeposition. Pristine CNTs, without any treatment like acid functionalization, were used. Anionic surfactant sodium dodecyl sulfate (SDS) was used to increase the wettability of the [...] Read more.

Cu-carbon nanotubes (CNTs) composite coatings with high CNT content and uniformly distributed CNTs were successfully prepared via jet electrodeposition. Pristine CNTs, without any treatment like acid functionalization, were used. Anionic surfactant sodium dodecyl sulfate (SDS) was used to increase the wettability of the CNTs and improve the content of incorporated CNTs. With an appropriate SDS concentration (300 mg/L) in the electrolyte, the incorporated CNT content is as high as 2.84 wt %, much higher than the values reported using conventional electrodeposition (0.42–1.05 wt %). The high-content CNTs were uniformly distributed in the composite coating. The surface morphology of this composite coating (2.84 wt % CNTs) was flat due to the uniform electric field in jet electrodeposition. In the wear test a with load of 1 N and sliding speed of 0.02 m/s, the wear rate of this composite coating was 1.3 × 10⁻² mg/Nm, 85.4% lower than that of pure Cu. The enhanced wear performance of Cu-CNTs composite coatings can be attributed to high CNT content and flat surface morphology. Full article

(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)

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