Coatings

32 pages, 641 KB

Open AccessEditor’s ChoiceReview

Synergistic Effects of Graphene and SiO₂ Nanoadditives on Dirt Pickup Resistance, Hydrophobicity, and Mechanical Properties of Architectural Coatings: A Systematic Review and Meta-Analysis

by Kseniia Burkovskaia, Michał Strankowski and Krzysztof Szafran

Coatings 2026, 16(1), 32; https://doi.org/10.3390/coatings16010032 - 28 Dec 2025

Viewed by 767

Abstract

This article provides a comprehensive review of the literature on the use of graphene-based nanomaterials (graphene oxide, reduced graphene oxide, and graphene nanoplatelets) and nanosilica (SiO₂) in architectural paint and coatings. The aim was to quantitatively assess their effect on dirt [...] Read more.

This article provides a comprehensive review of the literature on the use of graphene-based nanomaterials (graphene oxide, reduced graphene oxide, and graphene nanoplatelets) and nanosilica (SiO₂) in architectural paint and coatings. The aim was to quantitatively assess their effect on dirt pickup resistance, hydrophobicity, and mechanical properties. In a systematic search across ScienceDirect, Scopus, and Web of Science (2010–2025), 20 studies that met the set inclusion criteria were identified. We extracted and generalized data with random-effects models (REML) based on standardized mean differences, conducting subgroup and meta-regression analyses to assess filler type, loading, and binder system impact. The results reveal that graphene-based fillers and SiO₂ improve coating performance at the same time, and hybrid graphene-SiO₂ systems may provide a synergistic improvement depending on the binder matrix. Our results present the first quantitative evidence of graphene-SiO₂ interaction in the coating formulations, identify remaining research gaps, and indicate methods for designing next-generation facade paints with better dirt repellence, durability, and sustainability. Full article

(This article belongs to the Special Issue Modern Polymer Coating Materials Containing Graphene Derivatives)

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16 pages, 3852 KB

Open AccessEditor’s ChoiceArticle

ATP-Responsive ZIF-90 Nanocontainers Encapsulating Natural Antifoulants for Intelligent Marine Coatings

by Yanrong Chao, Xingyan Feng, Bingui Wang, Linghong Meng, Peng Qi, Yan Zeng and Peng Wang

Coatings 2026, 16(1), 7; https://doi.org/10.3390/coatings16010007 - 19 Dec 2025

Viewed by 601

Abstract

Marine biofouling presents a persistent challenge for maritime industries, necessitating the development of eco-friendly and intelligent antifouling strategies. In this work, an ATP-responsive nanocontainer was developed by encapsulating a natural organic compound (CS106-10), isolated from Talaromyces trachyspermus in cold seep sediments, together with [...] Read more.

Marine biofouling presents a persistent challenge for maritime industries, necessitating the development of eco-friendly and intelligent antifouling strategies. In this work, an ATP-responsive nanocontainer was developed by encapsulating a natural organic compound (CS106-10), isolated from Talaromyces trachyspermus in cold seep sediments, together with D-phenylalanine (D-Phe) into ZIF-90 nanoparticles (D-Phe/CS106-10@ZIF-90). These nanoparticles were incorporated into zinc acrylate resin to fabricate a novel self-polishing antifouling coating. CS106-10, as a natural antifoulant, provided efficient and environmentally sustainable bactericidal activity, while D-Phe acted as a synergistic adjuvant to inhibit and disrupt biofilm formation. More importantly, the ATP-responsive ZIF-90 framework enabled controlled, on-demand release of antifouling agents in response to local metabolic signals associated with biofilm growth. Laboratory and real-sea evaluations confirmed that the composite coating effectively suppressed biofilm formation and significantly reduced the required dosage of conventional toxic antifoulants. This study integrates a natural antifoulant with an ATP-responsive metal–organic framework, providing new insight for developing antifouling coatings. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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30 pages, 3827 KB

Open AccessEditor’s ChoiceReview

A Review of Anticoagulant Surface Modification Strategies for Blood-Contacting Materials: From Inertness to Bioinspired and Biointegration

by Shuguang Zhang, Zhixiang Deng, Yuhe Wang and Chao Zhao

Coatings 2025, 15(12), 1486; https://doi.org/10.3390/coatings15121486 - 16 Dec 2025

Viewed by 1337

Abstract

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility [...] Read more.

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility on the device surface, holding significant potential for clinical application. This article systematically elaborates on the latest research progress in the surface anticoagulant modification of blood-contacting materials. It analyzes and discusses the main strategies and their evolution, spanning from physically inert carbon-based coatings and heparin-based drug-functionalized surfaces to hydrophilic/hydrophobic dynamic physical barriers, biologically signaling regulatory coatings, and bio-integrative/regenerative endothelium-mimicking surfaces. The advantages and limitations of the respective methods are outlined, and the potential for synergistic application of multiple strategies is explored. A special emphasis is placed on current research hotspots regarding novel anticoagulant surface technologies, such as hydrogel coatings, liquid-infused surfaces, and 3D-printed endothelialization, aiming to provide insights and references for developing long-term, safe, and hemocompatible cardiovascular implantable devices. Full article

(This article belongs to the Collection Feature Paper Collection in 'Surface Coatings for Biomedicine and Bioengineering')

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16 pages, 3130 KB

Open AccessEditor’s ChoiceArticle

Mechanical, Structural, and Electrochemical Performance of Polyurethane Coatings for Corrosion Protection in Wind Energy Systems

by Oscar Xosocotla, María del Pilar Rodríguez-Rojas, Rafael Campos-Amezcua, Horacio Martínez, Victoria Bustos-Terrones and Oscar Guadarrama Pérez

Coatings 2025, 15(12), 1476; https://doi.org/10.3390/coatings15121476 - 15 Dec 2025

Cited by 1 | Viewed by 686

Abstract

Erosion of the leading edge is one of the most severe forms of damage in wind turbine blades, particularly in offshore wind farms. This degradation, mainly caused by rain, sand, and airborne particles through droplet impingement wear, significantly decreases blade aerodynamic efficiency and [...] Read more.

Erosion of the leading edge is one of the most severe forms of damage in wind turbine blades, particularly in offshore wind farms. This degradation, mainly caused by rain, sand, and airborne particles through droplet impingement wear, significantly decreases blade aerodynamic efficiency and power output. Since blades, typically made of fiber-reinforced polymer composites, are the most expensive components of a turbine, developing protective coatings is essential. In this study, polyurethane (PU) composite coatings reinforced with titanium dioxide (TiO₂) particles were added on glass fiber substrates by spray coating. The incorporation of TiO₂ improved the mechanical and electrochemical performance of the PU coatings. FTIR and XRD confirmed that low TiO₂ loadings (1 and 3 wt%) were well dispersed within the PU matrix due to hydrogen bonding between TiO₂ –OH groups and PU –NH groups. The PU/TiO₂ 3% coating exhibited ~61% lower corrosion current density (I_corr) compared to neat PU, indicating superior corrosion resistance. Furthermore, uniform TiO₂ dispersion resulted in statistically significant improvements (p < 0.05) in hardness, yield strength, elastic modulus, and adhesion strength. Overall, the PU/TiO₂ coatings, particularly at 3 wt% loading, show strong potential as protective materials for wind turbine blades, given their enhanced mechanical integrity and corrosion resistance. Full article

(This article belongs to the Special Issue Recent Progress in Thin Films and Surfaces: Deposition, Characterization and Various Applications)

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37 pages, 15016 KB

Open AccessEditor’s ChoiceReview

Technical Analyses of Particle Impact Simulation Methods for Modern and Prospective Coating Spraying Processes

by Yi Wang and Sergii Markovych

Coatings 2025, 15(12), 1480; https://doi.org/10.3390/coatings15121480 - 15 Dec 2025

Viewed by 608

Abstract

With the growing requirements for multi-particle process simulation, improving computational accuracy, efficiency, and scalability has become a critical challenge. This study generally focused on comprehensive analyses of existing numerical methods for simulating particle–substrate interactions in gas–thermal spraying (including gas–dynamic spraying processes), covering both [...] Read more.

With the growing requirements for multi-particle process simulation, improving computational accuracy, efficiency, and scalability has become a critical challenge. This study generally focused on comprehensive analyses of existing numerical methods for simulating particle–substrate interactions in gas–thermal spraying (including gas–dynamic spraying processes), covering both single-particle and multi-particle models to develop practical recommendations for the optimization of modern coating spraying processes. First of all, this paper systematically analyzes the key limitations of current approaches, including their inability to handle high deformations effectively or high computational complexity and their insufficient accuracy in dynamic scenarios. A comparative evaluation of four numerical methods (Lagrangian, Arbitrary Lagrangian–Eulerian (ALE), Coupled Eulerian–Lagrangian (CEL), and Smoothed Particle Hydrodynamics (SPH)) revealed their strengths and weaknesses in modeling of real gas–thermal spraying processes. Furthermore, this study identifies the limitations of the widely used Johnson–Cook (JC) constitutive model under extreme conditions. The authors considered the Zerilli–Armstrong (ZA), Mechanical Threshold Stress (MTS), and Preston–Tonks–Wallace (PTW) models as more realistic alternatives to the Jonson–Cook model. Finally, comparative analyses of theoretical and realistic deformation and defect-generation processes in gas–thermal coatings emphasize the critical need for fundamental changes in the simulation strategy for modern gas–thermal spraying processes. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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15 pages, 697 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Optical Properties at 1550 nm of Ion-Beam Sputtered Silicon Nitride Thin Films

by Diksha, Alex Amato, Gianluigi Maggioni, Christophe Michel, David Hofman, Massimo Granata and Jessica Steinlechner

Coatings 2025, 15(12), 1465; https://doi.org/10.3390/coatings15121465 - 10 Dec 2025

Viewed by 896

Abstract

Coating Brownian thermal noise is a major limitation to the sensitivity of gravitational-wave detectors. To reduce it, future detectors are planned to operate at cryogenic temperatures. This implies a change of their mirror coating materials and the use of a longer laser wavelength, [...] Read more.

Coating Brownian thermal noise is a major limitation to the sensitivity of gravitational-wave detectors. To reduce it, future detectors are planned to operate at cryogenic temperatures. This implies a change of their mirror coating materials and the use of a longer laser wavelength, such as 1550 nm. A stack of amorphous silicon and silicon nitride layers has previously been proposed as a promising combination of low- and high-refractive index materials to realize low-noise highly-reflective coatings. An essential step towards such coatings is the production of both materials via ion-beam sputtering. In this paper, for the first time, we present a study of the optical properties at 1550 nm of silicon nitride thin films deposited via ion beam sputtering. The refractive index and optical absorption as a function of post-deposition heat treatment temperature are investigated using a spectrophotometer and a photo-thermal common-path interferometer. Finally, we discuss the prospect of combining this material with amorphous silicon. Full article

(This article belongs to the Section Thin Films)

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16 pages, 2645 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Direct Measurement of Effective Electrical Capacitance in Systems with a Constant-Phase Element Behavior Using the Example of Barrier Coatings

by Andrzej Miszczyk

Coatings 2025, 15(12), 1429; https://doi.org/10.3390/coatings15121429 - 5 Dec 2025

Cited by 1 | Viewed by 903

Abstract

For various reasons, many dielectric and electrochemical systems exhibit behavior described by a constant-phase element (CPE) instead of a pure capacitor. However, in many applications, it is desirable to determine the electrical capacitance of such systems as a physically meaningful quantity. For this [...] Read more.

For various reasons, many dielectric and electrochemical systems exhibit behavior described by a constant-phase element (CPE) instead of a pure capacitor. However, in many applications, it is desirable to determine the electrical capacitance of such systems as a physically meaningful quantity. For this purpose, models are developed that allow for the conversion of the parameters of the studied system into the so-called effective electrical capacitance of the system. This study aims to replace model-based effective capacitance estimation with an approach based on direct measurements using electrochemical impedance spectroscopy (EIS). This approach utilizes the phenomenon of electrical resonance in the studied system. Using the described approach, the effective electrical capacitance of the coating system on steel was determined during over 300 h of exposure in Harrison’s solution. The CPE parameters were also determined during exposure. Using the Brasher–Kingbury equation, the kinetics of water absorption by the coating were compared using the obtained effective capacitance and the CPE parameter (pseudocapacitance). It was observed that using the effective capacitance yields significantly lower values of water content in the coating. The proposed method eliminates the uncertainty associated with speculative modeling and enables reliable tracking of the dielectric and electrochemical properties of systems, which is particularly important in batteries, supercapacitors, sensors, and protective coatings, where capacitance is a key indicator of performance and degradation. Full article

(This article belongs to the Special Issue Anti-Corrosion Coatings: New Ideas to Make Them More Effective)

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15 pages, 5434 KB

Open AccessEditor’s ChoiceArticle

Improving Boundary Lubrication of Phenolic-Based Coatings via Rare Earth Compound-Promoted Transfer Film Growth

by Guitao Li, Delong Wang, Huimin Qi and Ga Zhang

Coatings 2025, 15(12), 1417; https://doi.org/10.3390/coatings15121417 - 3 Dec 2025

Viewed by 517

Abstract

Polymer composite coatings are promising for tribological protection, with stable transfer films being key to their friction-reducing and anti-wear performance, yet the mechanism by which rare-earth compounds, known to enhance polymer tribological properties, regulate transfer film growth remains unclear. In this work, the [...] Read more.

Polymer composite coatings are promising for tribological protection, with stable transfer films being key to their friction-reducing and anti-wear performance, yet the mechanism by which rare-earth compounds, known to enhance polymer tribological properties, regulate transfer film growth remains unclear. In this work, the tribological performance of phenolic resin (PF)-based coatings filled with lanthanum oxide (La₂O₃) and lanthanum fluoride (LaF₃) was systematically investigated. The results demonstrate that the friction coefficients of 5La₂O₃/PF and 3LaF₃/PF decrease to 0.024 and 0.031, representing a 79.66% and 73.95% reduction compared to pure PF, which compensates for the inadequacy of oil lubrication. Tribochemical analyses and characterizations of tribofilm structures confirm that complex tribochemical reactions involving rare-earth compounds occur, promoting the growth of a solid-lubricating tribofilm at the boundary lubrication interface. This work provides a theoretical foundation for the design of high-performance polymer lubricating coatings. Full article

(This article belongs to the Special Issue Tribological and Corrosion Properties of the Surfaces)

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19 pages, 5883 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Pulse-Controlled Electrodeposition of Ni/ZrO₂ with Coumarin Additive: A Parametric Study

by Maria Myrto Dardavila and Constantina Kollia

Coatings 2025, 15(12), 1400; https://doi.org/10.3390/coatings15121400 - 1 Dec 2025

Viewed by 496

Abstract

Ni/ZrO₂ composite coatings are increasingly employed, yet the influence of organic additives under a pulse current regime on their electrodeposition remains insufficiently addressed. This study investigates the combined effect of pulse frequency (0.01–100 Hz) and coumarin concentration (0–2 mmol L⁻¹) [...] Read more.

Ni/ZrO₂ composite coatings are increasingly employed, yet the influence of organic additives under a pulse current regime on their electrodeposition remains insufficiently addressed. This study investigates the combined effect of pulse frequency (0.01–100 Hz) and coumarin concentration (0–2 mmol L⁻¹) on the co-deposition behavior, microstructure, and properties of Ni/ZrO₂ coatings electrodeposited from a Watts-type bath. The structural, morphological, and compositional features were analyzed through SEM/EDS, FE-SEM, and XRD, while microhardness and surface roughness were determined to establish processing–structure–property correlations. The results revealed that coumarin acts as an effective levelling agent, promoting smoother and finer-grained coatings while modifying ZrO₂ incorporation and Ni crystallographic orientation. Increasing coumarin concentration led to a notable refinement of nickel crystallites and a rise in hardness, reaching values close to 650 HV under optimal PC conditions. Pulse frequency was found to strongly influence the microstructural characteristics and particle co-deposition rates, particularly at low frequencies, where a balance between additive adsorption and current modulation favored particle incorporation and enhanced the microhardness. It was demonstrated that the synergistic control of pulse parameters and coumarin concentration enables the design of Ni/ZrO₂ composite coatings with tailored microstructure, low roughness, and superior hardness for demanding applications. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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24 pages, 8476 KB

Open AccessEditor’s ChoiceArticle

Ferroelectric Phase Stabilization and Charge-Transport Mechanisms in Doped HfO₂ Thin Films: Influence of Dopant Chemistry and Thickness

by Florin Năstase, Nicoleta Vasile, Silviu Vulpe, Cosmin Romanițan, Raluca Gavrilă, Oana Brîncoveanu, Lucia Monica Veca and Miron Adrian Dinescu

Coatings 2025, 15(12), 1396; https://doi.org/10.3390/coatings15121396 - 29 Nov 2025

Viewed by 1212

Abstract

Ferroelectricity in hafnium oxide (HfO₂)-based thin films has emerged as a scalable pathway toward CMOS-compatible non-volatile memories and logic devices. This study examines how dopant chemistry and film thickness influence the stabilization of the ferroelectric phase in ALD-grown HfO₂ thin [...] Read more.

Ferroelectricity in hafnium oxide (HfO₂)-based thin films has emerged as a scalable pathway toward CMOS-compatible non-volatile memories and logic devices. This study examines how dopant chemistry and film thickness influence the stabilization of the ferroelectric phase in ALD-grown HfO₂ thin films doped with Zr, Al, and Y. Structural, morphological, and electrical characterizations were carried out using AFM, GIXRD, P–E, in-plane I/W–E, and C–V measurements on films with thicknesses of 7 nm and 100 nm. AFM revealed atomically smooth and dense surfaces (R_q < 0.5 nm), while GIXRD confirmed the stabilization of the orthorhombic Pca2₁ phase in doped 7 nm films and its relaxation toward the monoclinic phase at 100 nm. The 7 nm HfZrO and HfYO films exhibited robust ferroelectric hysteresis with remanent polarization values up to 60 μC·cm⁻², whereas HfAlO showed a narrower but still distinct switching response. In-plane I/W–E characteristics indicated a combination of Poole–Frenkel and injection-limited conduction, consistent with defect-assisted polarization reversal and asymmetric contact barriers. At 100 nm, all films showed reduced polarization and partially dielectric behavior, as corroborated by the C–V data. These results demonstrate that nanoscale confinement, dopant-induced strain, and oxygen vacancy related defect chemistry collectively stabilize the orthorhombic ferroelectric phase, with Zr doping providing the most favorable balance between polarization strength and leakage control. Full article

(This article belongs to the Special Issue Recent Developments in Thin Films for Technological Applications)

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19 pages, 10290 KB

Open AccessEditor’s ChoiceArticle

Influence of Mo Content on the Microstructure and Mechanical Properties of Cu-Mo Composites Fabricated by Mechanical Alloying and Spark Plasma Sintering

by Jie Wu, Xiuqing Li and Qingxia Yang

Coatings 2025, 15(12), 1387; https://doi.org/10.3390/coatings15121387 - 27 Nov 2025

Cited by 1 | Viewed by 541

Abstract

In this work, Mo particles were incorporated into a Cu matrix, with the hope of retaining the advantageous properties of Cu while improving its mechanical performance. Mechanical ball milling was employed to fabricate Cu-Mo composite powders with different Mo concentrations; the Mo particles [...] Read more.

In this work, Mo particles were incorporated into a Cu matrix, with the hope of retaining the advantageous properties of Cu while improving its mechanical performance. Mechanical ball milling was employed to fabricate Cu-Mo composite powders with different Mo concentrations; the Mo particles were incorporated at mass fractions of 5%, 10%, 15%, and 20%, which were subsequently densified by spark plasma sintering (SPS) to achieve a high-density composite. Phase identification and microstructural analysis were performed using X-ray diffraction (XRD). Tensile strength, compressive strength, and Vickers hardness measurements were performed to evaluate the mechanical performance of the Cu-Mo composite. Microstructural characterization of the tensile specimen was conducted via electron backscatter diffraction (EBSD), energy dispersive X-ray spectroscopy (EDS), and field-emission scanning electron microscopy (FE-SEM). The results demonstrate a consistent decrease in grain size and a corresponding increase in density with higher Mo content in the composite. For Cu-15wt%Mo composite, the Vickers hardness is 135 HV, compressive strength is 300 MPa, and tensile strength is 371 MPa. Compared with pure Cu, they were increased by 74%, 115%, and 64%, respectively. The main strengthening mechanisms have been revealed. This research can offer a foundation and reference for designing and developing high-performance Cu-Mo composite. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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22 pages, 7329 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation and Modelling of the Wear Resistance of Diamond Roller Dressers Made of Synthetic Diamonds with Mixed Grit Size

by Irina Aleksandrova and Hristian Mitev

Coatings 2025, 15(12), 1376; https://doi.org/10.3390/coatings15121376 - 24 Nov 2025

Viewed by 520

Abstract

The wear resistance of diamond dressing rolls depends on the manufacturing technology used and the characteristics of the working diamond layer, such as the type and grain size of the diamond grains, the type of bond, and the concentration and distribution of the [...] Read more.

The wear resistance of diamond dressing rolls depends on the manufacturing technology used and the characteristics of the working diamond layer, such as the type and grain size of the diamond grains, the type of bond, and the concentration and distribution of the diamonds. To optimise the lifetime of diamond rolls made of synthetic diamonds using the electroplating method, this paper proposes an innovative approach to compacting the intergranular spaces by treating them with diamond grains finer than the main fraction. To implement this approach, analytical dependencies were derived for the distance between the diamond grains. Intensive wear of the diamond roller bond was observed when the distance was exceeded as a result of contact with the abrasive grains of the grinding wheel. A ratio between the grain sizes of the main and additional diamond fractions is also recommended. Diamond roller dressers made of synthetic diamonds with a medium or high strength and a mixed grit size were created and their wear resistance was studied during the uni-directional and counter-directional dressing of electrocorundum grinding wheels using the plunge-grinding method. Theoretical and experimental models were constructed to predict the lifetime and the wear of diamond rolls in relation to the radial feed rate, the dressing speed ratio, the dress-out time, and the grit size ratio. Multi-objective optimisation based on a genetic algorithm was used to determine the optimal dressing conditions, ensuring the best combination of the maximum lifetime and minimum wear of the diamond rolls. The results obtained confirm the validity and correctness of the proposed approach for increasing the wear resistance of diamond roller dressers. Full article

(This article belongs to the Special Issue Fatigue and Wear Mechanisms of Different Surface Coatings for Industrial Application)

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18 pages, 3647 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Amorphous Carbon Layers Deposited by Various Magnetron Sputtering Techniques

by Rafal Chodun, Lukasz Skowronski, Marek Trzcinski, Dobromil Zaloga, Katarzyna Nowakowska-Langier, Piotr Domanowski and Krzysztof Zdunek

Coatings 2025, 15(12), 1367; https://doi.org/10.3390/coatings15121367 - 22 Nov 2025

Viewed by 718

Abstract

This study investigates the synthesis and characterization of amorphous carbon (a-C) layers using three magnetron sputtering (MS) techniques: Pulsed MS (PMS), Gas Injection MS (GIMS), and High Power GIMS (HiPGIMS). The primary objective was to understand how these methods influence the sp³ [...] Read more.

This study investigates the synthesis and characterization of amorphous carbon (a-C) layers using three magnetron sputtering (MS) techniques: Pulsed MS (PMS), Gas Injection MS (GIMS), and High Power GIMS (HiPGIMS). The primary objective was to understand how these methods influence the sp³/sp² hybridization ratio, a critical parameter for tailoring the properties of amorphous carbon. Plasma diagnostics via Optical Emission Spectroscopy revealed distinct discharge characteristics, with HiPGIMS exhibiting the highest current density and plasma ionization. Structural and compositional analyses using Raman Spectroscopy and X-ray Photoelectron Spectroscopy (XPS) demonstrated a clear trend: sp³ content increased significantly from PMS to GIMS to HiPGIMS, reaching up to 50% (Raman) and 39% (XPS). This enhancement is attributed to the higher plasma density and more energetic ion bombardment in HiPGIMS, which promotes the formation of sp³ bonds. Ellipsometric spectroscopy further supported these findings, showing that HiPGIMS produced layers with the widest bandgap, indicative of higher sp³ content. The research highlights the effectiveness of advanced MS techniques, particularly HiPGIMS, in precisely controlling the sp³/sp² ratio and thereby the electrical, optical, and mechanical properties of a-C layers for various applications. Full article

(This article belongs to the Special Issue Present Status of Thin Films and Coatings Fabricated by Magnetron Sputtering)

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16 pages, 4514 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation of Scaling and Materials’ Performance of EHLA-Fabricated Cladding in Simulated Geothermal Brine

by David Martelo, Erfan Abedi Esfahani, Namrata Kale, Tomaso Maccio and Shiladitya Paul

Coatings 2025, 15(12), 1366; https://doi.org/10.3390/coatings15121366 - 22 Nov 2025

Cited by 2 | Viewed by 836

Abstract

This study investigates the corrosion and scaling behaviour of Extreme High-speed Laser Application (EHLA)-fabricated corrosion-resistant alloy (CRA) claddings under simulated geothermal brine conditions. EHLA 316L stainless steel and alloy 625 coatings were produced and tested in simulated brine (chloride–carbonate–silica geothermal brine) at 70 [...] Read more.

This study investigates the corrosion and scaling behaviour of Extreme High-speed Laser Application (EHLA)-fabricated corrosion-resistant alloy (CRA) claddings under simulated geothermal brine conditions. EHLA 316L stainless steel and alloy 625 coatings were produced and tested in simulated brine (chloride–carbonate–silica geothermal brine) at 70 °C for 720 h to evaluate the influence of additive manufacturing (AM) microstructures on corrosion performance. The EHLA coatings exhibited dense, metallurgically bonded microstructures with minimal porosity. Microstructural analysis revealed Nb- and Mo-rich segregation in EHLA 625 and fine columnar dendritic morphology in all coatings. EHLA 625 developed a stable passive film with only a thin deposit of Mg-O-containing compounds, whereas EHLA 316L exhibited localised pitting and significant Si- and Mg-containing scale accumulation, especially in as-built conditions. Surface finishing reduced corrosion activity by minimising roughness and defect-driven localised attack. Critical pitting temperature (CPT) tests confirmed the superior localised corrosion resistance of EHLA 625 relative to EHLA 316L under laboratory conditions. While these results indicate promising corrosion and scaling resistance of EHLA coatings, further process optimisation and post-deposition thermal treatments might be required to achieve coating performance comparable to wrought alloys. The results indicate the potential of EHLA-fabricated coatings for producing corrosion and scaling resistance surfaces. Full article

(This article belongs to the Special Issue Engineered Coatings for a Sustainable Future)

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17 pages, 6617 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Ultrahigh-Speed Deposition of Diamond-like Carbon on a Pipe Surface Using a Scanning Deposition Method via Local High-Density Plasma

by Akihiko Ito, Masahiro Esaki, Su-Min Bae, Taketo Nagai, Hiroyuki Kousaka and Toru Harigai

Coatings 2025, 15(11), 1348; https://doi.org/10.3390/coatings15111348 - 19 Nov 2025

Viewed by 443

Abstract

This study presents a highly effective method for depositing diamond-like carbon (DLC) films onto pipe substrates using a scanning deposition by plasma enhanced chemical vapor deposition. A microwave–sheath voltage combination plasma was employed to generate local high-density plasma along a rotating pipe. While [...] Read more.

This study presents a highly effective method for depositing diamond-like carbon (DLC) films onto pipe substrates using a scanning deposition by plasma enhanced chemical vapor deposition. A microwave–sheath voltage combination plasma was employed to generate local high-density plasma along a rotating pipe. While conventional contact-mode deposition using a metal contactor suffers from arcing and surface damage due to unstable sliding contact during rotation, a non-contact deposition using a metal antenna was developed to overcome these limitations. Electromagnetic field simulations were conducted to evaluate microwave power absorption in various antenna geometries, showing that the flat-plate antenna demonstrated the most effective power coupling. Subsequent scanning deposition experiments to a rotating pipe using flat-plate antennas of different lengths revealed that the 100 mm configuration achieved the highest deposition volume rate (exceeding that of the contact-mode) while avoiding arcing. Optical emission observations during deposition confirmed the formation of high-density plasma surrounding the flat-plate antenna and Raman spectroscopy of the deposited film showed typical spectra of DLC films. The deposition rates of DLC-coated pipe showed no significant variation with respect to rotational angle, suggesting that rotation during deposition contributes to achieving uniform film thickness along the circumferential direction of the pipe. Full article

(This article belongs to the Special Issue Plasma Coating and Interface Technology: New Horizons in Surface Science)

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11 pages, 2509 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydrothermal Carbonization Coating on AISI 1018 Steel for Seawater Corrosion Protection

by Yong X. Gan

Coatings 2025, 15(11), 1346; https://doi.org/10.3390/coatings15111346 - 19 Nov 2025

Cited by 1 | Viewed by 575

Abstract

The seawater corrosion behavior of a plain carbon steel covered with hydrothermally carbonized coating was studied. Hydrothermal carbonization of sugar (sucrose) dissolved in water with a concentration of 10 wt.% at 200 °C for 4 h was carried out to produce a carbonized [...] Read more.

The seawater corrosion behavior of a plain carbon steel covered with hydrothermally carbonized coating was studied. Hydrothermal carbonization of sugar (sucrose) dissolved in water with a concentration of 10 wt.% at 200 °C for 4 h was carried out to produce a carbonized coating on the steel. The corrosion resistance of the steel with and without the carbonized coating was evaluated by polarization tests in seawater. The Tafel slopes were calculated using polarization data. The corrosion current and the potential of corrosion were determined to examine the effect of the carbonized coating on the corrosion behavior of the steel. In addition, AC impedance measurements on the steel without and with the hydrothermal carbonization coating were performed in a three-electrode cell with a Ag/AgCl reference electrode, platinum counter electrode, and seawater electrolyte. It was found that hydrothermal carbonization of sugar generated a continuous carbon-rich layer on the surface of the steel. This carbon layer is highly corrosion-resistant as shown by the decrease in the corrosion current. It is concluded that the hydrothermally carbonized coating has the nature of passivation films, and it can slow down the corrosion rate of the plain carbon steel in seawater. The impedance of the steel without hydrothermal carbonization coating is very low. With hydrothermal carbonization coating, an increase in the resistance and the capacitive response of the coating/seawater interface was observed. Full article

(This article belongs to the Special Issue Advances in Corrosion-Resistant Coatings, 2nd Edition)

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18 pages, 10563 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Biological Response and Antimicrobial Behaviour of Sputtered TiO₂/Cu Coatings Deposited on Ti6Al4V Alloy

by Maria P. Nikolova, Yordan Handzhiyski, Tanya V. Dimitrova, Andreana Andreeva, Stefan Valkov, Maria Ormanova and Margarita D. Apostolova

Coatings 2025, 15(11), 1341; https://doi.org/10.3390/coatings15111341 - 18 Nov 2025

Viewed by 613

Abstract

Nanostructured TiO₂/Cu coatings were deposited on Ti6Al4V alloy by a two-step glow-discharge sputtering process and evaluated for their structural, electrochemical, and biological properties. Dual-acid etching produced microroughened substrates before TiO₂ layer deposition, followed by surface Cu sputtering with varied deposition [...] Read more.

Nanostructured TiO₂/Cu coatings were deposited on Ti6Al4V alloy by a two-step glow-discharge sputtering process and evaluated for their structural, electrochemical, and biological properties. Dual-acid etching produced microroughened substrates before TiO₂ layer deposition, followed by surface Cu sputtering with varied deposition times. Characterisation by AFM, OM, SEM/EDS, and XRD confirmed the formation of TiO₂ with Cu/Cu₂O-containing hybrid coatings with good adhesion to the substrate. Increasing Cu deposition enhanced surface hydrophobicity and copper ion release. EIS measurements proved that the coatings retained stable protective behaviour in simulated body fluid (SBF). Antibacterial tests against Escherichia coli showed up to 98% improved efficacy compared to bare Ti6Al4V, confirming the strong antimicrobial role of copper. However, MG63 osteoblast-like cells exhibited reduced viability even after pre-immersion in PBS, suggesting that cytotoxicity was associated not only with excess Cu ion release but also with direct interaction between cells and surface Cu nanostructures. Overall, the results indicate that TiO₂/Cu coatings provide excellent antimicrobial activity, good protection and strong adhesion, but their limited biocompatibility highlights the need for fine-tuned copper incorporation in future biomedical implant applications. Full article

(This article belongs to the Special Issue Coatings for Biomedical Applications: Biocompatibility, Drug Delivery, Antibiosis and Tissue Engineering)

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14 pages, 1015 KB

Open AccessEditor’s ChoiceArticle

Gellan Gum-Based Edible Coatings Enriched with Scenedesmus spp. Extract to Enhance the Postharvest Quality and Shelf Life of Mangoes

by Rafael González-Cuello, Joaquín Hernández-Fernández and Rodrigo Ortega-Toro

Coatings 2025, 15(11), 1333; https://doi.org/10.3390/coatings15111333 - 16 Nov 2025

Viewed by 695

Abstract

Mango (Mangifera indica L.) is one of the most important tropical fruits; however, its limited postharvest shelf life restricts its commercial distribution. This study aimed to assess the influence of edible coatings formulated with high-acyl gellan gum (HAG), low-acyl gellan gum (LAG), [...] Read more.

Mango (Mangifera indica L.) is one of the most important tropical fruits; however, its limited postharvest shelf life restricts its commercial distribution. This study aimed to assess the influence of edible coatings formulated with high-acyl gellan gum (HAG), low-acyl gellan gum (LAG), and their blends enriched with an aqueous extract of Scenedesmus spp. on the preservation of mango quality during postharvest storage. The film-forming solutions based on HAG, LAG, and their combination (HAG/LAG) were enriched with Scenedesmus spp. extract at two concentrations (1 and 2% w/v) and subsequently employed for coating whole mango fruits. The coated samples were analyzed throughout storage to assess their physicochemical and physiological quality attributes, including weight loss, soluble solids content, titratable acidity, color variation, malondialdehyde accumulation, antioxidant activity, respiration rate, ethylene production, and hydrogen peroxide content. The results showed that coated fruits exhibited reduced color changes, lower weight loss, and improved visual acceptability compared to controls. Coatings containing 2% Scenedesmus spp., particularly HAG-based formulations, significantly decreased malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) accumulation, enhanced antioxidant capacity, and stabilized respiration rate and ethylene production, delaying ripening and senescence. These effects were associated with the oxygen barrier properties of gellan gum and the antioxidant compounds present in Scenedesmus spp. Overall, the findings highlight that HAG coatings enriched with Scenedesmus spp. represent a sustainable and efficient approach to extend shelf life and preserve the physicochemical and nutritional attributes of mangoes. Full article

(This article belongs to the Special Issue Advances in Food Technology: Bioactive Films and Coatings for Food Packaging)

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27 pages, 3139 KB

Open AccessEditor’s ChoiceReview

Intelligent Sensing and Responsive Separators for Lithium Batteries Using Functional Materials and Coatings for Safety Enhancement

by Junbing Tang, Zhiyan Wang, Yongzheng Zhang, Duan Bin and Hongbin Lu

Coatings 2025, 15(11), 1325; https://doi.org/10.3390/coatings15111325 - 13 Nov 2025

Viewed by 1655

Abstract

With the increasing demand for high-energy-density lithium batteries, the role of separators has expanded significantly beyond conventional ion conduction and physical isolation. By integrating sensors and introducing functional coatings, separators have gained the ability to monitor internal states in real time and achieve [...] Read more.

With the increasing demand for high-energy-density lithium batteries, the role of separators has expanded significantly beyond conventional ion conduction and physical isolation. By integrating sensors and introducing functional coatings, separators have gained the ability to monitor internal states in real time and achieve adaptive regulation. This paper systematically reviews the latest research progress on separators modified with functional materials and coatings to achieve information sensing, intelligent response, and multifunctional integration. Notably, an electrochemical sensor based on MXene/MWCNTs-COOH/MOF-808 has been developed for rapid chemical detection; a fully printed ultra-thin flexible multifunctional sensor array has enabled multi-parameter synchronous monitoring; an ion-selective MOF-808-EDTA separator has induced uniform lithium-ion flux; and a PVDF-HFP/LLZTO/PVDF-HFP trilayer separator has maintained structural integrity at 300 °C. These innovative achievements fully demonstrate the enormous potential of intelligent separators in monitoring internal battery states, inhibiting dendrite growth, preventing thermal runaway, and significantly enhancing battery safety, cycle life, and energy density. This points to a transformative development path for the next generation of batteries with higher safety and intelligence. Full article

(This article belongs to the Special Issue Recent Progress on Functional Films and Surface Science)

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24 pages, 14785 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Characteristics of the Novel Electron Beam Hardening Technology for Submicron Bainitic Steels in the Context of Its Application in the Production of Gears and Comparison with the Competitive Laser Beam Technology

by Piotr Śliwiński, Andrzej N. Wieczorek, Emilia Skołek, Marciniak Szymon, Arkadiusz Pawlikowski, Paweł Nuckowski, Łukasz Reimann, Marek S. Węglowski, Jerzy Dworak and Paweł Pogorzelski

Coatings 2025, 15(11), 1321; https://doi.org/10.3390/coatings15111321 - 12 Nov 2025

Viewed by 604

Abstract

The objective of this study was to investigate electron beam hardening (EBH) technology and compare its performance with laser beam hardening (LBH) in the context of manufacturing components such as gears, which increasingly employ submicron bainitic steels. Given the stringent demands for durability [...] Read more.

The objective of this study was to investigate electron beam hardening (EBH) technology and compare its performance with laser beam hardening (LBH) in the context of manufacturing components such as gears, which increasingly employ submicron bainitic steels. Given the stringent demands for durability and fatigue resistance of gear teeth, identifying an optimal surface hardening method is essential for extending service life. Comprehensive analyses, including light and electron microscopy, hardness testing, tribocorrosion testing, and X-ray diffraction for phase composition, were conducted. The EBH-treated layer exhibited a slightly higher hardness (by 26 HV) compared to the LBH-treated layer (average 654 HV), while the base material measured 393 HV. The EBH process produced a uniform hardness distribution with a subsurface zone of reduced hardness. In contrast, LBH resulted in a surface oxide layer absent in EBH due to its vacuum environment. Both techniques reduced the residual austenite content in the surface layer from 22.5% to approximately 1.3%–1.4%. Notably, EBH achieved comparable hardening effects with nearly half the energy input of LBH, demonstrating superior energy efficiency and industrial feasibility. Application of the developed EBH process to an actual gear component confirmed its practical potential for modern gear manufacturing. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

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18 pages, 1595 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Nanosilica Fillers on Photopolymerisation Behaviour and Mechanical Performance of Dental Resin Composites

by Mariola Robakowska and Łukasz Gierz

Coatings 2025, 15(11), 1316; https://doi.org/10.3390/coatings15111316 - 11 Nov 2025

Cited by 1 | Viewed by 643

Abstract

The performance of dental composites is strongly dependent on the type and content of ceramic fillers incorporated into the resin matrix. In this study, the effect of nanosilica (NS) fillers on the curing kinetics, physicochemical, thermal, and mechanical properties of Bis-GMA/TEGDMA-based dental composites [...] Read more.

The performance of dental composites is strongly dependent on the type and content of ceramic fillers incorporated into the resin matrix. In this study, the effect of nanosilica (NS) fillers on the curing kinetics, physicochemical, thermal, and mechanical properties of Bis-GMA/TEGDMA-based dental composites was systematically investigated. A series of nanocomposites containing various weight fractions of NS was prepared and evaluated. The photocuring behaviour was analysed using differential scanning calorimetry (DSC), enabling the determination of polymerisation rate coefficients (propagation k_p and bimolecular termination k_t^b) and double bond conversion. The presence of nanosilica was found to influence chain mobility, as evidenced by changes in glass transition temperature (T_g). Rheological measurements provided insight into viscosity changes induced by NS incorporation, while mechanical tests confirmed reinforcement effects. A moderate but statistically significant correlation was observed between the NS content and mechanical performance. The results obtained correlate the rheological, kinetic, thermal, and mechanical properties of multiple types of silica in a single resin system using a consistent methodology. In addition, the results highlight the role of nanosilica in the regulation of the curing dynamics and the increase in the mechanical integrity of methacrylate-based dental composites, representing a promising strategy for the development of next-generation restorative materials. Full article

(This article belongs to the Special Issue Advanced Biomaterials, Coatings and Techniques: Applications in Medicine and Dentistry, 2nd Edition)

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20 pages, 3571 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Novel Omniphobic Teflon/PAI Composite Membrane Prepared by Vacuum-Assisted Dip-Coating Strategy for Dissolved Gases Separation from Transformer Oil

by Wei Zhang, Qiwei Yang, Yuanyuan Jin, Yanzong Meng, Leyu Shen, Xuran Zhu, Haifeng Gao and Chuan Chen

Coatings 2025, 15(11), 1319; https://doi.org/10.3390/coatings15111319 - 11 Nov 2025

Cited by 1 | Viewed by 659

Abstract

Omniphobic membranes have gained extensive attention for mitigating membrane wetting in robust membrane separation owing to the super-repulsion toward water and oil. In this study, a Teflon/PAI composite membrane with omniphobic characteristics was prepared by a vacuum-assisted dip-coating strategy on the PAI hollow [...] Read more.

Omniphobic membranes have gained extensive attention for mitigating membrane wetting in robust membrane separation owing to the super-repulsion toward water and oil. In this study, a Teflon/PAI composite membrane with omniphobic characteristics was prepared by a vacuum-assisted dip-coating strategy on the PAI hollow fiber membrane. A series of characterizations on morphological structure, surface chemical composition, wettability, permeability, mechanical properties, and stability were systematically investigated for pristine PAI and Teflon/PAI composite membranes. Subsequently, the experiment was conducted to explore the oil–gas separation performance of membranes, with standard transformer oil containing dissolved gas as the feed. The results showed that the Teflon AF2400 functional layer was modified, and C-F covalent bonds were introduced on the composite membrane surface. The Teflon/PAI composite membrane exhibited excellent contact angles of 156.3 ± 1.8° and 123.0 ± 2.5° toward DI water and mineral insulating oil, respectively, indicating omniphobicity. After modification, the membrane tensile stress at break increased by 23.0% and the mechanical performance of the composite membrane was significantly improved. In addition, the Teflon/PAI composite membrane presented satisfactory thermal and ultrasonic stability. Compared to the previous membranes, the Teflon/PAI composite membrane presented a thinner Teflon AF2400 separation layer. Furthermore, the omniphobic membrane demonstrated anti-wetting performance by reaching the dynamic equilibrium within 2 h for the dissolved gases separated from the insulating oil. This suggests an omniphobic membrane as a promising alternative for oil–gas separation in monitoring the operating condition of oil-filled electrical equipment online. Full article

(This article belongs to the Special Issue Advances in Polymer Composite Coatings and Films)

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18 pages, 3328 KB

Open AccessEditor’s ChoiceArticle

Influence of Primer Layer Configuration and Substrate Heterogeneity on the Overall Interfacial Performance of Waterborne Acrylic Coatings on Flattened Bamboo

by Yingyue Yu, Hong Chen, Shuangshuang Wu and Wei Xu

Coatings 2025, 15(11), 1307; https://doi.org/10.3390/coatings15111307 - 10 Nov 2025

Viewed by 579

Abstract

Flattened bamboo (FB) exhibits pronounced structural and chemical heterogeneity between outer and inner layers and between nodes and internodes. These variations critically influence its interfacial performance with waterborne acrylic coatings. This study aimed to clarify how primer layer configuration and substrate heterogeneity jointly [...] Read more.

Flattened bamboo (FB) exhibits pronounced structural and chemical heterogeneity between outer and inner layers and between nodes and internodes. These variations critically influence its interfacial performance with waterborne acrylic coatings. This study aimed to clarify how primer layer configuration and substrate heterogeneity jointly affect the coating adhesion, hardness, and abrasion resistance of FB. Three coating schemes—one primer and one topcoat (1P1T), two primers and one topcoat (2P1T), and three primers and one topcoat (3P1T)—were applied to four types of FB substrates defined by layer and structural position. Adhesion, pencil hardness, and abrasion resistance were measured according to GB/T standards, complemented by surface roughness, contact angle, XPS, and SEM analyses. Results showed that substrate heterogeneity dominated coating behavior. The parenchyma-rich inner-layer internodes, characterized by higher polarity (O/C = 0.296) and rougher texture, exhibited stronger adhesion and superior abrasion stability, whereas the fiber-dense outer layer nodes, with lower polarity (O/C = 0.262), showed weaker bonding. Increasing the number of primer layers improved film continuity only when the substrate microstructure allowed sufficient primer penetration. The combined findings indicate that coating adhesion and wear stability are primarily governed by substrate composition and surface polarity rather than by coating thickness. These results provide scientific and practical guidance for optimizing primer application and surface preparation in the industrial finishing of bamboo-based decorative panels, while also highlighting the environmental and economic advantages of waterborne coating optimization for sustainable bamboo manufacturing. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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12 pages, 1544 KB

Open AccessEditor’s ChoiceReview

Toughness Characterization Methods for Diamond-like Carbon Films

by Jiahao Liu, Zhifang Yang and Xiang Yu

Coatings 2025, 15(11), 1302; https://doi.org/10.3390/coatings15111302 - 7 Nov 2025

Viewed by 784

Abstract

Diamond-like carbon (DLC) films exhibit superior tribological properties; however, their widespread adoption in precision manufacturing is hampered by inherent brittleness and a lack of reliable toughness characterization methods at the micrometer scale. This review critically examines existing techniques for evaluating DLC film toughness, [...] Read more.

Diamond-like carbon (DLC) films exhibit superior tribological properties; however, their widespread adoption in precision manufacturing is hampered by inherent brittleness and a lack of reliable toughness characterization methods at the micrometer scale. This review critically examines existing techniques for evaluating DLC film toughness, highlighting limitations due to film thickness constraints and subjective failure definitions. We focus on two prominent micro-scale methods: impact testing and scratch testing. Impact toughness is assessed through energy absorption analysis based on impact crater morphology, including crack patterns and delamination areas. Scratch toughness is evaluated using critical loads (Lc₁, Lc₂) and the derived Crack Propagation Resistance (CPRS) parameter, complemented by microscopic failure analysis. We argue that neither method alone suffices for comprehensive toughness assessment. Instead, we propose a synergistic strategy integrating both techniques to provide a practical and comprehensive evaluation encompassing energy- and stress-based failure mechanisms under varying loading conditions. This approach offers a practical framework for developing tougher DLC coatings. Full article

(This article belongs to the Special Issue Advanced Functional Coatings for Corrosion Protection)

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18 pages, 3630 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Discovery and Quantification of Microplastic Generation in the Recycling of Coated Paper-Based Packaging

by Andrea Marinelli, Sara Baracani, Daniele Bussini, Alessandra Boschi, Andrea Lucotti, Luca Paterlini, Maria Vittoria Diamanti and Barbara Del Curto

Coatings 2025, 15(11), 1284; https://doi.org/10.3390/coatings15111284 - 3 Nov 2025

Viewed by 1130

Abstract

Microplastics (MPs) are found almost everywhere in the environment and the food chain. The long-term effects of MPs on living organisms are still unclear, so preventing anthropogenic MP generation has become crucial. Fibre-based packaging recycling is investigated here, shedding light on possible MP [...] Read more.

Microplastics (MPs) are found almost everywhere in the environment and the food chain. The long-term effects of MPs on living organisms are still unclear, so preventing anthropogenic MP generation has become crucial. Fibre-based packaging recycling is investigated here, shedding light on possible MP generation and its consequences. As a typically overlooked source of secondary MPs, cellulosic packaging often consists of thin polymeric coatings that can fragment during recycling. Dispersion coating technology for paper substrates is considered here. The coating formulation was tagged with rhodamine-B and investigated using semi-automatised techniques, including fluorescence microscopy, optical microscopy, and Raman spectroscopy. The results raise concerns as the coating under investigation (8 g/m²) broke into more than 75,000 secondary MPs, whose equivalent diameter and particle count density in the recycled material averaged 75.4 µm and 4.7 particles/mm², respectively. Wastewater analysis found finer particles (average equivalent diameter: 51.4 µm) with a higher particle count density (6.7 particles/mm²). Overall, 72% of the retrieved particles were smaller than 100 µm. Without proper wastewater screening, such particles (representing 87% in the wastewater filter) may enter the environment, hence representing a hazard for living organisms including humans. Full article

(This article belongs to the Topic Environmental Sensitivity and Safety Assessment of Materials, 2nd Edition)

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19 pages, 5147 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Aqueous Polyhydroxyalkanoate Solution-Based Knife Coatings: An Alternative Approach to the Production of Coated Cotton Fabrics

by Marta A. Teixeira, Joana Castro, Beatriz Lima, Catarina Guise, Helena Vilaça and Carla Joana Silva

Coatings 2025, 15(11), 1278; https://doi.org/10.3390/coatings15111278 - 3 Nov 2025

Viewed by 2909

Abstract

Footwear is traditionally manufactured using non-biodegradable polymers and leather, raising well-documented environmental and health concerns related to their production and disposal. This study explores polyhydroxyalkanoates (PHAs) as sustainable alternatives for bio-based footwear components. A stable aqueous suspension of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was successfully formulated [...] Read more.

Footwear is traditionally manufactured using non-biodegradable polymers and leather, raising well-documented environmental and health concerns related to their production and disposal. This study explores polyhydroxyalkanoates (PHAs) as sustainable alternatives for bio-based footwear components. A stable aqueous suspension of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was successfully formulated and applied to cotton fabrics via knife-coating. Various formulations, with and without additives and employing natural or synthetic thickeners, were evaluated in terms of surface morphology, wettability, permeability, and durability. The 10% PHBHHx formulation provided the best balance between material efficiency, coating uniformity, and surface performance. Additives and thermal treatment both influenced wettability, reducing contact angles and enhancing water vapor permeability. Notably, coatings with additives and hot pressing exhibited the highest permeability (68.0 ± 3.1 L/m²/s; 651.0 ± 5.4 g/m²/24 h), while additive-free, non-pressed coatings showed significantly lower values (19.5 ± 4.4 L/m²/s; 245.6 ± 66.2 g/m²/24 h), likely due to excessive compaction. Abrasion resistance remained excellent across all samples, especially with thermal treatment, withstanding 51,200 cycles. Washing resistance results revealed a synergistic effect between additives and heat, promoting long-term hydrophobicity and coating adhesion. Overall, PHBHHx coatings demonstrated potential to enhance water resistance while maintaining breathability, representing a sustainable and effective solution for functional and technical footwear applications. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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22 pages, 9246 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Structure, Composition and Optical Properties of Thin Films of Copper Sulphide and Bismuth Sulphide Deposited on Various Textiles by the SILAR Method

by Vėja Sruogaitė and Valentina Krylova

Coatings 2025, 15(11), 1266; https://doi.org/10.3390/coatings15111266 - 2 Nov 2025

Viewed by 689

Abstract

The synthesis of thin films in multilayer structures on different textiles is of interest due to their potential use in flexible solar absorber coatings and thin-film solar cells. The aim of the study was to deposit bismuth(III) sulphide and copper(II) sulphide thin films [...] Read more.

The synthesis of thin films in multilayer structures on different textiles is of interest due to their potential use in flexible solar absorber coatings and thin-film solar cells. The aim of the study was to deposit bismuth(III) sulphide and copper(II) sulphide thin films on various textiles at the same time. This was achieved using the sustainable and cost-effective successive ionic layer adsorption and reaction (SILAR) method. The study examined how the elemental distribution, phase composition, crystallinity, surface morphology, and optical features of the resulting films are determined by the intrinsic structure and material makeup of structural textiles. The analysis used data from scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD), as well as ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. Depending on the textiles used, the formed films were polycrystalline and rich in copper. According to the findings, the normalised atomic percentages were as follows: Cu, 57.66–68.75%; Bi, 1.19–5.26%; S, 30.06–38.63%. The direct transition optical energy gap values varied from 1.3 to 2.88 eV, while the indirect varied from 0.9 to 2.25 eV, and the refractive index from 1.3 to 1.8. These properties were influenced by the composition of the textiles and the films themselves. These properties directly impact the films’ applications. Full article

(This article belongs to the Special Issue Advances in Coated Fabrics and Textiles)

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18 pages, 12230 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Two-Level Surface Roughness on Superhydrophobicity

by Yanfei Wang, Mengdan You and Qiang Sun

Coatings 2025, 15(11), 1269; https://doi.org/10.3390/coatings15111269 - 2 Nov 2025

Cited by 1 | Viewed by 873

Abstract

Biomimetic superhydrophobic surfaces have become a focal point of recent research, driven by their promise in diverse applications. Among these, the lotus and rose effects are of particular interest due to their contrasting adhesion characteristics. Given that superhydrophobicity is closely related to the [...] Read more.

Biomimetic superhydrophobic surfaces have become a focal point of recent research, driven by their promise in diverse applications. Among these, the lotus and rose effects are of particular interest due to their contrasting adhesion characteristics. Given that superhydrophobicity is closely related to the hierarchical structures of these surfaces, investigating the effects of two-level roughness on superhydrophobicity is crucial. In our previous work, we introduced a wetting parameter (W_Roughness), strongly correlated with the geometric characteristics of surface roughness, to elucidate the superhydrophobic behavior of solid surfaces. This parameter predicts the existence of a critical wetting parameter (W_Roughness,c) during the Wenzel–Cassie transition. For two-level surface roughness composed of primary and secondary roughness, the W_Roughness of the two-level surface is influenced by the geometric characteristics of both primary and secondary roughness. Furthermore, when secondary roughness is added to a primary roughness surface in the Wenzel state, the resulting two-level roughness can exhibit various superhydrophobic states, such as the Wenzel state, Wenzel–Cassie transition, or Cassie state, depending on the characteristics of the secondary roughness. To further investigate the influence of two-level roughness on superhydrophobicity, molecular dynamics (MD) simulations were also conducted. Full article

(This article belongs to the Special Issue Superhydrophobic Coatings, 2nd Edition)

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14 pages, 5002 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Perception of Structural Colors in Nanostructured Anodic Aluminum Oxide Films

by Woong Ki Jang, Yoo Su Kang, Young Ho Seo and Byeong Hee Kim

Coatings 2025, 15(11), 1260; https://doi.org/10.3390/coatings15111260 - 1 Nov 2025

Cited by 1 | Viewed by 1188

Abstract

This study investigates the fabrication of anodic aluminum oxide (AAO)/Al bilayer films using a two-step aluminum anodization process and explores the perception and prediction of structural colors through these films. A composite AAO film with an AAO/Ni/Al structure was fabricated by electroplating an [...] Read more.

This study investigates the fabrication of anodic aluminum oxide (AAO)/Al bilayer films using a two-step aluminum anodization process and explores the perception and prediction of structural colors through these films. A composite AAO film with an AAO/Ni/Al structure was fabricated by electroplating an AAO/Al bilayer film with an AAO/Al structure. The fabricated composite AAO film was used to produce structural colors through changes in optical characteristics caused by Ni nanoplugs. Constructive-interference wavelengths resulting from variations in the pore diameter and interpore distance of AAO/Al bilayer films and composite AAO films were predicted using the Bragg–Snell law, with a maximum error margin of 9%. Additionally, the composite AAO film exhibited RGB colors within the predicted constructive-interference wavelength range. These results demonstrate that structural colors can be reliably predicted by estimating the constructive-interference wavelengths of composite AAO films. The approach provides a practical design rule for target colors in AAO-based coatings under normal incidence. The key advance is a single closed-form rule that links D_t, D_int, D_P, and D_ni to λ_{_peak} at normal incidence, enabling forward and inverse color design without numerical optimization. Full article

(This article belongs to the Section Thin Films)

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20 pages, 10310 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Studies on the Tribocorrosion Properties of an Iron Alloy Produced by Wire Arc Additive Manufacturing Subjected to Multi-Stage Heat Treatment

by Andrzej N. Wieczorek, Arkadiusz Stachowiak, Paweł Nuckowski, Marcin Staszuk, Marek S. Węglowski, Adam Gołaszewski and Szymon Marciniak

Coatings 2025, 15(11), 1265; https://doi.org/10.3390/coatings15111265 - 1 Nov 2025

Viewed by 672

Abstract

The paper addresses tribocorrosion resistance studies of components made from the iron alloy Fe (0.21% C, 0.8% Si, 1.29% Mn, 1.34% Cr) using the Wire Arc Additive Manufacturing (WAAM) technology. The authors have developed their original heat treatment technology, where oil baths are [...] Read more.

The paper addresses tribocorrosion resistance studies of components made from the iron alloy Fe (0.21% C, 0.8% Si, 1.29% Mn, 1.34% Cr) using the Wire Arc Additive Manufacturing (WAAM) technology. The authors have developed their original heat treatment technology, where oil baths are used, leading to an increase in impact strength. This treatment combines processes such as austenitising, martensitic hardening, tempering, and austempering. As part of the research tests, tribocorrosion wear measurements were conducted in a 3.5% NaCl solution on both heat-treated and non-treated samples. The measurements showed lower tribocorrosion wear in the samples subjected to the novel heat treatment. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

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41 pages, 10559 KB

Open AccessEditor’s ChoiceReview

Interfacial Bonding and Residual Stress of Single Splats on Solid Substrates: A Literature Review

by Chao Kang and Motoki Sakaguchi

Coatings 2025, 15(11), 1259; https://doi.org/10.3390/coatings15111259 - 31 Oct 2025

Cited by 1 | Viewed by 1484

Abstract

The impingement of a molten droplet on a solid surface, forming a “splat,” is a fundamental phenomenon observed across numerous industrial surface engineering techniques. For example, thermal spray deposition is widely used to create metal, ceramic, polymer, and composite coatings that are vital [...] Read more.

The impingement of a molten droplet on a solid surface, forming a “splat,” is a fundamental phenomenon observed across numerous industrial surface engineering techniques. For example, thermal spray deposition is widely used to create metal, ceramic, polymer, and composite coatings that are vital for aerospace, biomedical, electronics, and energy applications. Significant progress has been made in understanding droplet impact behavior, largely driven by advancements in high-resolution and high-speed imaging techniques, as well as computational resources. Although droplet impact dynamics, splat morphology, and interfacial bonding mechanisms have been extensively reviewed, a comprehensive overview of the mechanical behaviors of single splats, which are crucial for coating performance, has not been reported. This review bridges that gap by offering an in-depth analysis of bonding strength and residual stress in single splats. The various experimental techniques used to characterize these properties are thoroughly discussed, and a detailed review of the analytical models and numerical simulations developed to predict and understand residual stress evolution is provided. Notably, the complex interplay between bonding strength and residual stress is then discussed, examining how these two critical mechanical attributes are interrelated and mutually influence each other. Subsequently, effective strategies for improving interfacial bonding are explored, and key factors that influence residual stress are identified. Furthermore, the fundamental roles of splat flattening and formation dynamics in determining the final mechanical properties are critically examined, highlighting the challenges in integrating fluid dynamics with mechanical analysis. Thermal spraying serves as the primary context, but other relevant applications are briefly considered. Cold spray splats are excluded because of their distinct bonding and stress generation mechanisms. Finally, promising future research directions are outlined to advance the understanding and control of the mechanical properties in single splats, ultimately supporting the development of more robust and reliable coating technologies. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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15 pages, 2938 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhanced Lateral Growth of Homoepitaxial (001) Diamond by Microwave Plasma Chemical Vapor Deposition with Nitrogen Addition

by Tzu-I Yang, Chia-Yen Chuang, Jun-Bin Huang, Cheng-Jung Ko, Wei-Lin Wang and Li Chang

Coatings 2025, 15(11), 1256; https://doi.org/10.3390/coatings15111256 - 30 Oct 2025

Viewed by 1313

Abstract

Diamond, as an exceptional material with many superior properties, requires a single crystal in a reasonably large size for practical industrial applications. However, achieving large-area single-crystal diamond (SCD) growth without the formation of polycrystalline rims remains challenging. Microwave plasma chemical vapor deposition (MPCVD) [...] Read more.

Diamond, as an exceptional material with many superior properties, requires a single crystal in a reasonably large size for practical industrial applications. However, achieving large-area single-crystal diamond (SCD) growth without the formation of polycrystalline rims remains challenging. Microwave plasma chemical vapor deposition (MPCVD) using a gas mixture of 10% CH₄-H₂ was used for the homoepitaxial growth of (001) SCD. The effect of nitrogen gas addition in the range of 0–2000 ppm on lateral growth was investigated. Deposition with 180 ppm N₂ over a growth duration of 20 h to reach a thickness of 0.95 mm resulted in significantly enhanced lateral growth without the appearance of a polycrystalline diamond (PCD) rim for the grown diamond, and the total top surface area of SCD increased by an area gain of 1.6 relative to the substrate. The corresponding vertical and lateral growth rates were 47.3 µm/h and 52.5 µm/h, respectively. Characterization by Raman spectroscopy and atomic force microscopy (AFM) revealed uniform structural integrity across the whole surface from the laterally grown regions to the center, including the entire expanded area, in terms of surface morphology and crystalline quality. Moreover, measurements of the etch pit densities (EPDs) showed a substantial reduction in the laterally grown regions, approximately an order of magnitude lower than those in the central region. The high quality of the homoepitaxial diamond layer was further verified with (004) X-ray rocking curve analysis, showing a narrow full width at half maximum (FWHM) of 11 arcsec. Full article

(This article belongs to the Special Issue Thin-Film Synthesis, Characterization and Properties)

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13 pages, 3181 KB

Open AccessEditor’s ChoiceArticle

Load and Velocity Dependence of Friction at Iron–Silica Interfaces: An Atomic-Scale Study

by Xiang Jiao, Guochen Huang, Ouwen Chen, Qian Cheng, Chenchen Peng and Guoqing Wang

Coatings 2025, 15(11), 1252; https://doi.org/10.3390/coatings15111252 - 29 Oct 2025

Cited by 1 | Viewed by 924

Abstract

Understanding the microscopic interaction between agricultural tillage tools and soil is essential for improving wear resistance. In this study, molecular dynamics (MD) simulations are employed to investigate the tribological behavior of the Fe–SiO₂ interface under varying loads and sliding velocities. The results [...] Read more.

Understanding the microscopic interaction between agricultural tillage tools and soil is essential for improving wear resistance. In this study, molecular dynamics (MD) simulations are employed to investigate the tribological behavior of the Fe–SiO₂ interface under varying loads and sliding velocities. The results demonstrate that the coefficient of friction increases with both normal load and sliding velocity, accompanied by a clear running-in stage. Under high loads, significant plastic deformation occurs, characterized by asymmetric atomic pile-up, expansion of the strain field, and heterogeneous von Mises strain distribution. Energy analysis reveals intensified kinetic and potential energy variations, indicating enhanced defect accumulation and interfacial non-equilibrium states. Temperature distributions are highly localized at the interface, with thermal saturation observed under high-velocity conditions. Mean square displacement (MSD) results confirm that higher loads and velocities promote atomic migration and plastic flow. This study provides atomic-scale insights into wear mechanisms under extreme mechanical conditions, offering theoretical support for the design of durable soil-engaging components in agricultural machinery. Full article

(This article belongs to the Special Issue Tribological Behavior and Corrosion Resistance Characterization of Advanced Materials and Coatings)

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17 pages, 2610 KB

Open AccessFeature PaperEditor’s ChoiceArticle

An Artificial Intelligence for the Analysis of a DC Magnetron Sputtering System Combined with a Particle-in-Cell Simulation

by Yeun Jung Kim and Hae June Lee

Coatings 2025, 15(11), 1248; https://doi.org/10.3390/coatings15111248 - 27 Oct 2025

Cited by 1 | Viewed by 679

Abstract

A numerical method to estimate the plasma characteristics with the variation in control parameters is suggested with an artificial intelligence model using limited finite datasets. A transformer-based regression method was applied to estimate the spatial profiles of plasma characteristics in a DC magnetron [...] Read more.

A numerical method to estimate the plasma characteristics with the variation in control parameters is suggested with an artificial intelligence model using limited finite datasets. A transformer-based regression method was applied to estimate the spatial profiles of plasma characteristics in a DC magnetron sputtering system from limited data obtained by a two-dimensional particle-in-cell simulation under varying pressure. Based on the obtained simulation data, an artificial intelligence method successfully predicts the energy and angular distribution of ions incident on the target. This approach enables the quantitative estimation of the impact of various system parameter changes on plasma characteristics using only a limited number of simulation results. It is beneficial for practical applications, such as process optimization, because the ion energy and angle distributions can be estimated very fast without simulating all the cases. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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13 pages, 3789 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhanced Mechanical Durability of Polymeric Nanowires via Carbyne-Enriched Plasma Coatings for Bactericidal Action

by Dimitrios Nioras, Dionysia Kefallinou, Dimosthenis Ioannou, Luis Antonio Panes-Ruiz, Bergoi Ibarlucea, Gianaurelio Cuniberti, Tianshu Lan, Angeliki Tserepi and Evangelos Gogolides

Coatings 2025, 15(11), 1247; https://doi.org/10.3390/coatings15111247 - 27 Oct 2025

Cited by 3 | Viewed by 4198

Abstract

Carbon-based materials have emerged as promising biomaterials due to their biocompatibility and inherent antibacterial properties. Carbyne, a unique allotrope of carbon, characterized by sp-hybridized carbons forming alternating single and triple bonds, exhibits exceptional toughness. Herein, we explore the potential of carbyne-enriched plasma coatings [...] Read more.

Carbon-based materials have emerged as promising biomaterials due to their biocompatibility and inherent antibacterial properties. Carbyne, a unique allotrope of carbon, characterized by sp-hybridized carbons forming alternating single and triple bonds, exhibits exceptional toughness. Herein, we explore the potential of carbyne-enriched plasma coatings for antibacterial applications in conjunction with micro- and nano-textured polymeric surfaces. We investigate and characterize carbyne-enriched plasma coatings onto superhydrophilic or superhydrophobic poly (methyl methacrylate) (PMMA) plasma micro-nanotextured surfaces. Our analysis evaluates the wetting properties and durability of these surfaces, particularly in liquid immersion conditions. The integration of carbyne-enriched plasma coatings serves a dual purpose: it enhances the chemical bactericidal action and protects surface micro-nanostructures from deformation due to capillary forces thanks to the material’s innate toughness. The results show that the micro-nanotextured and carbyne-enriched coated PMMA surfaces exhibit a significant bactericidal activity as expressed by a bactericidal index of approximately 50%, owing to the combined effect of both the surface topography and the plasma-deposited carbyne coating. Full article

(This article belongs to the Special Issue Emerging Trends in Plasma Coating and Interface Technologies)

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23 pages, 3697 KB

Open AccessEditor’s ChoiceArticle

Microfluidic Edible Coatings: Multiphase VOF Modeling, Physicochemical Properties, Image Analysis, and Applications in Fried Foods

by Cristian Aarón Dávalos-Saucedo, Giovanna Rossi-Márquez, Sergio Rodríguez-Miranda and Carlos E. Castañeda

Coatings 2025, 15(11), 1245; https://doi.org/10.3390/coatings15111245 - 26 Oct 2025

Cited by 1 | Viewed by 981

Abstract

Edible coatings are widely used to modulate oil uptake and moisture in fried foods. In this study, we evaluated a microfluid-assisted flow-blurring spray against conventional application by dipping/spraying, focusing on the coating efficiency and preliminary implications for sustainable process. This study combines benchtop [...] Read more.

Edible coatings are widely used to modulate oil uptake and moisture in fried foods. In this study, we evaluated a microfluid-assisted flow-blurring spray against conventional application by dipping/spraying, focusing on the coating efficiency and preliminary implications for sustainable process. This study combines benchtop experiments with a near-nozzle numerical analysis where the gas–liquid interface and primary breakup are modeled using the Volume of Fluid (VOF) approach implemented in OpenFOAM, configured for a flow-blurring geometry to generate whey protein isolate (WPI) coatings. Viscosity, density, solid content, and contact angle were validated experimentally and used in the simulation setup. An image-based droplet pipeline quantified spray characteristics, yielding a volumetric median diameter D₅₀ = 83.69 µm and confirming process uniformity. Contact angles showed marked substrate dependence: hydrophilic surfaces, 68°–85°; hydrophobic surfaces, 95°–110°. For turkey sausages, sessile-drop contact angles were not determinable (N.D.) due to wicking/roughness; wettability was therefore assessed on smooth surrogates and via performance metrics. Fit-for-purpose simulation procedures are outlined. Microfluidic application (WPI-McF) lowered oil uptake versus uncoated controls. Together, robust modeling, targeted image analytics, and high-precision microfluidics enable rational tuning of coating microstructure and barrier performance, offering a scalable pathway to reduce lipid content and enhance fried food quality. Full article

(This article belongs to the Section Coatings for Food Technology and System)

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18 pages, 3050 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimization of Gold Thin Films by DC Magnetron Sputtering: Structure, Morphology, and Conductivity

by Wojciech Bulowski, Katarzyna Skibińska, Piotr Żabiński and Marek Wojnicki

Coatings 2025, 15(11), 1240; https://doi.org/10.3390/coatings15111240 - 24 Oct 2025

Cited by 3 | Viewed by 1941

Abstract

Gold thin films were deposited on quartz substrates by DC magnetron sputtering to fabricate electrodes for electrochemical and resistive sensing applications. The influence of sputtering parameters on film thickness, structure, and electrical properties was systematically investigated. XRD analysis revealed a predominant (111) crystallographic [...] Read more.

Gold thin films were deposited on quartz substrates by DC magnetron sputtering to fabricate electrodes for electrochemical and resistive sensing applications. The influence of sputtering parameters on film thickness, structure, and electrical properties was systematically investigated. XRD analysis revealed a predominant (111) crystallographic orientation. Microstrain values, determined via Williamson–Hall (W–H) analysis, were low (below 0.013) and closely correlated with surface roughness trends. AFM measurements showed that the surface roughness increased with film thickness. Electrical resistivity decreased linearly with increasing thickness and exhibited a critical grain size of approximately 25 nm, beyond which conductivity improved markedly. These results demonstrate the strong dependence of Au thin-film morphology and performance on deposition conditions, offering practical guidelines for optimizing their application in functional sensing devices. Full article

(This article belongs to the Special Issue Thin Films and Nanostructures for Electronics)

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18 pages, 7364 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhanced Moisture Management in Textiles via Spray-Coated Water-Based Polyhydroxyalkanoate Dispersions

by Marta A. Teixeira, Wael Almustafa, Joana Castro, Catarina Guise, Helena Vilaça and Carla J. Silva

Coatings 2025, 15(11), 1237; https://doi.org/10.3390/coatings15111237 - 23 Oct 2025

Viewed by 1163

Abstract

Developing sustainable textile finishes that enhance moisture management and breathability remains a significant challenge in designing high-performance apparel. In this study, we propose an eco-friendly coating strategy utilizing an aqueous dispersion of poly(3-hydroxybutyrate)-diol (PHB.E.0), a member of the polyhydroxyalkanoate (PHA) family. This coating [...] Read more.

Developing sustainable textile finishes that enhance moisture management and breathability remains a significant challenge in designing high-performance apparel. In this study, we propose an eco-friendly coating strategy utilizing an aqueous dispersion of poly(3-hydroxybutyrate)-diol (PHB.E.0), a member of the polyhydroxyalkanoate (PHA) family. This coating was applied to woven polyester (PES) and cotton (CO) fabrics using a low-impact spray-coating technique, aiming to improve functional properties while maintaining environmental sustainability. This solvent-free process significantly reduces chemical usage and energy demand, aligning with sustainable manufacturing goals. Successful deposition of the coating was confirmed by scanning electron microscopy (SEM), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), elemental (C/O) analysis, and thermogravimetric analysis (TGA), which also revealed substrate-dependent thermal behaviour. Wettability, water absorption, and permeability tests showed that the coated fabrics retained their hydrophilic character. PHB.E.0 coatings led to a significant reduction in air permeability, particularly after hot pressing at 180 °C, from ≈670 to ≈171 L·m⁻² s⁻¹ for PES and from ≈50 to ≈30 L·m⁻²·s⁻¹ for CO, without compromising water vapor permeability. All coated samples maintained high breathability, essential for wearer comfort. These results demonstrate that PHB.E.0 coatings enhance wind resistance while preserving moisture vapor transport, offering a sustainable and effective solution for functional sportswear. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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14 pages, 1696 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Environmentally Durable Au-Based Low-e Coatings

by Wan Noor Sofia Wan Shamsuddin, Kamil Zuber, Peter J. Murphy and Marta Llusca Jane

Coatings 2025, 15(10), 1231; https://doi.org/10.3390/coatings15101231 - 21 Oct 2025

Cited by 1 | Viewed by 801

Abstract

Low-emissivity (low-e) coatings are used in architectural and automotive glazing for energy-saving applications. These are used to minimise heat transmission through the windows by reflection. Low-e coatings are semi-transparent coatings that typically comprise a metallic layer that reflects infrared light, sandwiched between two [...] Read more.

Low-emissivity (low-e) coatings are used in architectural and automotive glazing for energy-saving applications. These are used to minimise heat transmission through the windows by reflection. Low-e coatings are semi-transparent coatings that typically comprise a metallic layer that reflects infrared light, sandwiched between two dielectric layers that protect the metal and enhance its visible transmittance. Ag is usually used as the metallic layer because of its colour neutrality and low optical absorption in the visible range. However, Ag-based low-e coatings easily degrade upon atmosphere exposure; therefore, they need to be placed inside the cavities of multiple-pane windows. In this paper, Au was used as an alternative to Ag and was sandwiched between WO₃, SnO₂ and Nb₂O₅ dielectric layers. The thickness of each layer was optimised to achieve the highest visible transmittance and infrared reflectance. The durability of the coatings was assessed by means of corrosion and abrasion resistance tests. We demonstrate that the Nb₂O₅/Au/Nb₂O₅ coating system provides a visible light transmittance of 56%, an emissivity as low as 0.04 and outstanding corrosion resistance (1000 h of salt spray testing), indicating its excellent potential to be used as first surface low-e coating. Full article

(This article belongs to the Special Issue Novel Research on Optical Materials and Coatings)

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21 pages, 3658 KB

Open AccessEditor’s ChoiceReview

An Overview of Metallic Abradable Coatings in Gas Turbine Engines

by Kaue Bertuol, Bruno Edu Arendarchuck and Pantcho Stoyanov

Coatings 2025, 15(10), 1216; https://doi.org/10.3390/coatings15101216 - 16 Oct 2025

Cited by 2 | Viewed by 1890

Abstract

This review presents a comprehensive overview of metallic abradable coatings and the advanced testing methodologies used to evaluate their performance in gas turbine engines. Abradable materials are engineered to act as sacrificial coatings, enabling minimal blade tip wear while maintaining tight clearances between [...] Read more.

This review presents a comprehensive overview of metallic abradable coatings and the advanced testing methodologies used to evaluate their performance in gas turbine engines. Abradable materials are engineered to act as sacrificial coatings, enabling minimal blade tip wear while maintaining tight clearances between rotating blades and stationary components. Such functionality is critical in aerospace applications, where engines operate at high rotational speeds and across wide temperature ranges. The review examines the principal factors governing the design and selection of metallic-based abradable coatings, including material composition, thermal stability, and microstructural tailoring through the addition of phase modifiers, porosity formers, and solid lubricants. The performance of various metallic matrix materials is also discussed concerning their operational temperature ranges and wear characteristics. Particular attention is given to abradability evaluation methods, emphasizing the need to replicate engine-representative conditions to capture blade–coating interactions, frictional behavior, and wear mechanisms. This review consolidates advances in material compositions, microstructural engineering, and experimental testing, integrating perspectives from materials science, tribology, and methodology to guide the development of next-generation turbine coatings. It specifically addresses the lack of a unified review linking material design, thermal spray processes, and performance evaluation by summarizing key compositions, microstructures, and testing methods. Full article

(This article belongs to the Special Issue Research Progress and Prospect of Functional Thin Films & Hard Protective Coatings)

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24 pages, 3803 KB

Open AccessEditor’s ChoiceReview

Review of Preparation and Key Functional Properties of Micro-Arc Oxidation Coatings on Various Metal Substrates

by Ningning Li, Huiyi Wang, Qiuzhen Liu, Zhenjie Hao, Da Xu, Xi Chen, Datian Cui, Lei Xu and Yaya Feng

Coatings 2025, 15(10), 1201; https://doi.org/10.3390/coatings15101201 - 12 Oct 2025

Cited by 16 | Viewed by 2750

Abstract

Micro-arc oxidation (MAO) technology demonstrates remarkable advantages in fabricating ceramic coatings on lightweight alloys. For aluminum alloys, MAO rapidly forms dense, pore-free ceramic layers within minutes, significantly enhancing corrosion and wear resistance at low processing costs. In magnesium alloys, optimized electrolyte compositions and [...] Read more.

Micro-arc oxidation (MAO) technology demonstrates remarkable advantages in fabricating ceramic coatings on lightweight alloys. For aluminum alloys, MAO rapidly forms dense, pore-free ceramic layers within minutes, significantly enhancing corrosion and wear resistance at low processing costs. In magnesium alloys, optimized electrolyte compositions and process parameters enable composite coatings with a combination of high hardness and self-lubrication properties, while post-treatments like laser melting or corrosion inhibitors extend salt spray corrosion resistance. Titanium alloys benefit from MAO coatings with exceptional interfacial bonding strength and mechanical performance, making them ideal for biomedical implants and aerospace components. Notably, dense ceramic oxide films grown in situ via MAO on high-entropy alloys (HEAs) triple surface hardness and enhance wear/corrosion resistance. However, MAO applications on steel require pretreatments like aluminizing, thermal spraying, or ion plating. Current challenges include coating uniformity control, efficiency for complex geometries, and long-term stability. Future research focuses on multifunctional coatings (self-healing, antibacterial) and eco-friendly electrolyte systems to expand engineering applications. Full article

(This article belongs to the Special Issue Advances in Alloy Surface Mechanics: The Effects of Coating Technologies on Performance)

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28 pages, 8557 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Surface Optimization of Additively Manufactured (AM) Stainless Steel Components Using Combined Chemical and Electrochemical Post-Processing

by Pablo Edilberto Sanchez Guerrero, Andrew Grizzle, Daniel Fulford III, Juan Estevez Hernandez, Lucas Rice and Pawan Tyagi

Coatings 2025, 15(10), 1197; https://doi.org/10.3390/coatings15101197 - 11 Oct 2025

Viewed by 876

Abstract

The design and production of goods have been completely transformed by additive manufacturing (AM), which makes it possible to create components with intricate and complex geometries that were previously impossible or impractical to produce. However, current technologies continue to produce coarse-surfaced metal components [...] Read more.

The design and production of goods have been completely transformed by additive manufacturing (AM), which makes it possible to create components with intricate and complex geometries that were previously impossible or impractical to produce. However, current technologies continue to produce coarse-surfaced metal components that typically exhibit fatigue properties, resulting in component failure and unfavorable friction coefficients on the printed part. Therefore, to improve the surface quality of the fabricated parts, post-processing of AM-created components is required. With emphasis on electroless nickel plating, ChemPolishing (CP), and ElectroPolishing (EP), this study investigates post-processing methods for stainless steel that is additively manufactured (AM). The rough surfaces created by additive manufacturing (AM) restrict direct use. While ElectroPolishing (EP) achieves high material removal rates but may not be consistent, ChemPolishing (CP) offers uniform smoothening. Nickel plating enhances additive manufacturing (AM) products’ resistance to wear and scratches and corrosion protection. To optimize nickel deposition, medium (6%–9%) and high (10%–13%) phosphorus nickel was tested using the L9 Taguchi design of experiments (DOE). Mechanical properties, including scratch resistance and adhesion, were evaluated using the TABER 5900 reciprocating (Taber Industries, North Tonawanda, NY, USA) abraser apparatus, a 5 N scratch test, and ASTM B-733 thermal shock method. Surface analysis was performed with the KEYENCE VHX-7000 microscope (Keyence Corporation, Itasca, IL, USA), and chemical composition before and after nickel deposition was assessed via the ThermoFisher Phenom XL scanning electron microscope (SEM, Thermo Fisher Scientific, Waltham, MA, USA) Optimal processing conditions, determined using Qualitek-4 software, Version 20.1.0 revealed improvements in both surface finish and mechanical robustness. This comprehensive analysis underscores the potential of nickel-coated additive manufacturing (AM) parts for enhanced performance, offering a pathway to more durable and efficient additive manufacturing (AM) applications. Full article

(This article belongs to the Special Issue Recent Advances in Surface Functionalisation, 2nd Edition)

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43 pages, 1412 KB

Open AccessEditor’s ChoiceReview

Surface Modification of Screen-Printed Carbon Electrodes

by Naila Haroon and Keith J. Stine

Coatings 2025, 15(10), 1182; https://doi.org/10.3390/coatings15101182 - 9 Oct 2025

Cited by 7 | Viewed by 4244

Abstract

SPCEs are crucial for electrochemical sensing because of their portability, low cost, disposability, and ease of mass production. This study details their manufacture, surface modifications, electrochemical characterization, and use in chemical and biosensing. SPCEs integrate working, reference, and counter electrodes on PVC or [...] Read more.

SPCEs are crucial for electrochemical sensing because of their portability, low cost, disposability, and ease of mass production. This study details their manufacture, surface modifications, electrochemical characterization, and use in chemical and biosensing. SPCEs integrate working, reference, and counter electrodes on PVC or polyester substrates for compact sensor design. Surface modifications, such as plasma treatment (O₂, Ar), nanomaterial addition (AuNPs, GO, CNTs), polymer coatings, and MIPs, enhance performance. These changes improve sensitivity, selectivity, stability, and electron transport. Electrochemical methods such as CV, DPV, SWV, and EIS detect analytes, including biomolecules (glucose, dopamine, and pathogens) and heavy metals (Pb²⁺, As³⁺). Their applications include healthcare diagnostics, environmental monitoring, and food safety. Modified SPCEs enable rapid on-site analysis and offer strong potential to transform our understanding of the physical world. Full article

(This article belongs to the Collection Feature Papers Collection in 'Surface Characterization, Deposition and Modification')

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30 pages, 3410 KB

Open AccessEditor’s ChoiceReview

Application of Rejuvenators in Asphalt Binders: Classification and Micro- and Macro-Properties

by Chengwei Xing, Weichao Zhou, Bohan Zhu, Haozongyang Li and Shixian Tang

Coatings 2025, 15(10), 1177; https://doi.org/10.3390/coatings15101177 - 8 Oct 2025

Viewed by 1888

Abstract

Rejuvenating aged asphalt is critical for sustainable road construction and resource utilization. This paper systematically reviews the current research on rejuvenators, focusing on their classification and the micro-, and macro-properties of rejuvenated asphalt. Rejuvenators are categorized into mineral oil-based, bio-based, and compound types. [...] Read more.

Rejuvenating aged asphalt is critical for sustainable road construction and resource utilization. This paper systematically reviews the current research on rejuvenators, focusing on their classification and the micro-, and macro-properties of rejuvenated asphalt. Rejuvenators are categorized into mineral oil-based, bio-based, and compound types. Each type offers distinct advantages in recovering the performance of aged asphalt. Mineral oil-based rejuvenators primarily enhance low-temperature cracking resistance through physical dilution, while bio-based rejuvenators demonstrate superior environmental sustainability and stability. Compound rejuvenators, particularly those incorporating reactive compounds, show the best results in repairing degraded polymer modifiers and improving both low- and high-temperature properties of aged, modified asphalt. Atomic Force Microscopy (AFM), Fluorescence Microscopy (FM), and Scanning Electron Microscopy (SEM) have been applied to analyze the micro-properties of rejuvenated asphalt. These techniques have revealed that rejuvenators can restore the microstructure of aged asphalt by dispersing agglomerated asphaltenes and promoting molecular mobility. Functional groups and molecular weight changes, characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Gel Permeation Chromatography (GPC), indicate that rejuvenators effectively reduce oxidation products and molecular weight of aged asphalt, restoring its physicochemical properties. Macro-property evaluations show that rejuvenators significantly improve penetration, ductility, and fatigue resistance. Finally, this review identifies the key characteristics and challenges associated with rejuvenator applications and provides an outlook on future research directions. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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10 pages, 4407 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Charge Transport Properties of Polycrystalline CVD Diamond Films Deposited on Monocrystalline Si Substrate

by Kazimierz Paprocki, Kazimierz Fabisiak, Szymon Łoś, Wojciech Kozera, Tomasz Knapowski, Mirosław Szybowicz and Anna Dychalska

Coatings 2025, 15(10), 1171; https://doi.org/10.3390/coatings15101171 - 7 Oct 2025

Viewed by 871

Abstract

In this work, diamond/Si heterojunctions were fabricated by synthesizing a diamond layer directly on a monocrystalline n-type Si substrate. The diamond layers were characterized using micro-Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The current–voltage (I–V) characteristics of the heterojunctions were [...] Read more.

In this work, diamond/Si heterojunctions were fabricated by synthesizing a diamond layer directly on a monocrystalline n-type Si substrate. The diamond layers were characterized using micro-Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The current–voltage (I–V) characteristics of the heterojunctions were measured at room temperature. The heterojunctions exhibited rectifying behavior, confirming their diode-like nature. Based on thermionic emission theory, key electrical parameters of the heterojunction diodes—including the ideality factor (n) and carrier mobility (μ)—were estimated from the I–V characteristics. The I–V curves revealed large ideality factors ranging from 1.5 to 6.5, indicating the presence of deep trap states with densities between 2 × 10¹⁵ and 8 × 10¹⁶ eV⁻¹·cm⁻³. These variations were attributed to differences in the structural quality of the diamond layers and the effects of surface hydrogen termination. Full article

(This article belongs to the Special Issue Chemical Vapor Deposition (CVD): Technology and Applications)

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14 pages, 5385 KB

Open AccessEditor’s ChoiceArticle

Improvement of Water Erosion Resistance of Gypsum Mortars in the Historic Buildings for Conservation Purpose

by Yichen Sun, Ting Li, Jianing Dong, Yan Liu, Xiaoqin Yan, Yong Ling, Guang Huang and Fuwei Yang

Coatings 2025, 15(10), 1165; https://doi.org/10.3390/coatings15101165 - 5 Oct 2025

Cited by 1 | Viewed by 824

Abstract

Gypsum mortar is widely used in structures of architectural heritage. However, due to the high solubility of gypsum in water, it is easily destroyed by water erosion in outdoor environments, leading to the instability or even failure of the ancient buildings constructed with [...] Read more.

Gypsum mortar is widely used in structures of architectural heritage. However, due to the high solubility of gypsum in water, it is easily destroyed by water erosion in outdoor environments, leading to the instability or even failure of the ancient buildings constructed with it. To improve the water erosion resistance of gypsum mortar, the alcoholic solution of barium hydroxide was explored as the protective agent in this study. The method involves treating the gypsum mortar with the alcoholic solution of barium hydroxide and water in sequence. The mechanism of its action and protective properties were studied by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, conductivity meter, colorimeter, etc., and conclusions were made that the alcoholic solution of barium hydroxide has high permeability and its subsequent conversion to insoluble barium sulfate and calcium carbonate helps to increase the water erosion resistance of the solution. Additionally, the positive results such as the increase in mechanical strength from 20.80 HD to 60.94 HD, the reduction in water absorption from 18.37% to 15.75%, and a total color difference (ΔE*) of less than 3.0 indicated the application prospects of the proposed method in the conservation of the historical buildings made from gypsum mortar. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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14 pages, 3409 KB

Open AccessEditor’s ChoiceArticle

Synergistic ATO/SiO₂ Composite Coatings for Transparent Superhydrophobic and Thermal-Insulating Performance

by Guodong Qin, Lei Li and Qier An

Coatings 2025, 15(10), 1160; https://doi.org/10.3390/coatings15101160 - 4 Oct 2025

Viewed by 1280

Abstract

Multifunctional coatings integrating high transparency, thermal insulation, and self-cleaning properties are critically needed for optical devices and energy-saving applications, yet simultaneously optimizing these functions remains challenging due to material and structural limitations. This study designed a superhydrophobic transparent thermal insulation coating via synergistic [...] Read more.

Multifunctional coatings integrating high transparency, thermal insulation, and self-cleaning properties are critically needed for optical devices and energy-saving applications, yet simultaneously optimizing these functions remains challenging due to material and structural limitations. This study designed a superhydrophobic transparent thermal insulation coating via synergistic co-construction of micro–nano structures using antimony-doped tin oxide (ATO) and SiO₂ nanoparticles dispersed in an epoxy resin matrix, with surface modification by perfluorodecyltriethoxysilane (PFDTES) and γ-glycidyl ether oxypropyltrimethoxysilane (KH560). The optimal superhydrophobic transparent thermal insulating (SHTTI) coating, prepared with 0.6 g SiO₂ and 0.8 g ATO (SHTTI-0.6-0.8), achieved a water contact angle (WCA) of 162.4°, sliding angle (SA) of 3°, and visible light transmittance of 72% at 520 nm. Under simulated solar irradiation, it reduced interior temperature by 7.3 °C compared to blank glass. The SHTTI-0.6-0.8 coating demonstrated robust mechanical durability by maintaining superhydrophobicity through 40 abrasion cycles, 30 tape-peel tests, and sand impacts, combined with chemical stability, effective self-cleaning capability, and exceptional anti-icing performance that prolonged freezing time to 562 s versus 87 s for blank glass. This work provides a viable strategy for high-performance multifunctional coatings through rational component ratio optimization. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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19 pages, 7060 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Non-Invasive Multi-Analytical Insights into Renaissance Wall Paintings by Bernardino Luini

by Eleonora Verni, Michela Albano, Curzio Merlo, Francesca Volpi, Chaehoon Lee, Chiara Andrea Lombardi, Valeria Comite, Paola Fermo, Andrea Bergomi, Vittoria Guglielmi, Mattia Borelli, Carlo Mariani, Sabrina Samela, Lorenzo Vinco, Marta Ghirardello, Tommaso Rovetta, Giacomo Fiocco and Marco Malagodi

Coatings 2025, 15(9), 1113; https://doi.org/10.3390/coatings15091113 - 22 Sep 2025

Cited by 1 | Viewed by 1229

Abstract

The findings of non-invasive, multi-analytical research on two wall paintings located in the Santuario della Beata Vergine dei Miracoli in Saronno (Varese, Italy)—The Marriage of the Virgin and The Adoration of the Christ Child—are presented in this paper. The authorship of [...] Read more.

The findings of non-invasive, multi-analytical research on two wall paintings located in the Santuario della Beata Vergine dei Miracoli in Saronno (Varese, Italy)—The Marriage of the Virgin and The Adoration of the Christ Child—are presented in this paper. The authorship of the latter is up for controversy, while the former is unquestionably attributed to Bernardino Luini. The objective was to assess the compatibility of their color palettes through material comparison. A complementary suite of non-invasive techniques, including X-ray fluorescence (XRF), external reflection FTIR, Raman, visible reflectance spectroscopy and hyperspectral imaging, were employed to characterize pigments and surface materials without sampling. Results confirm the use of historically consistent pigments such as calcium carbonate, ochres, Naples yellow, smalt, azurite and lapis lazuli. Differences in the application of blue pigments—lapis lazuli in The Marriage of the Virgin and azurite in The Adoration of the Christ Child—may reflect workshop variation rather than separate authorship. Spectral imaging revealed pigment mixing and layering strategies, especially in skin tones and shadow modeling. This study underscores the significance of diagnostics as an interpretive instrument, capable of contextualizing Luini’s paintings within the context of Renaissance creative practice, providing a framework relevant to analogous inquiries. Full article

(This article belongs to the Special Issue Surface and Interface Analysis of Cultural Heritage, 2nd Edition)

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28 pages, 8495 KB

Open AccessEditor’s ChoiceArticle

Preparation of Tea Tree Essential Oil@Chitosan-Arabic Gum Microcapsules and Its Effect on the Properties of Waterborne Coatings

by Nana Zhang, Ye Zhu, Xiaoxing Yan and Jun Li

Coatings 2025, 15(9), 1105; https://doi.org/10.3390/coatings15091105 - 20 Sep 2025

Cited by 2 | Viewed by 997

Abstract

Furniture surfaces are prone to the accumulation of bacteria, fungi and other micro-organisms, especially in humid environments such as kitchens and bathrooms. The antimicrobial treatment of coatings has been demonstrated to enhance the performance of wood, prolong its service life, and improve hygiene [...] Read more.

Furniture surfaces are prone to the accumulation of bacteria, fungi and other micro-organisms, especially in humid environments such as kitchens and bathrooms. The antimicrobial treatment of coatings has been demonstrated to enhance the performance of wood, prolong its service life, and improve hygiene and safety. Consequently, by investigating the most effective preparation process for antimicrobial microcapsules and incorporating them into the coating, the coating can be endowed with antimicrobial properties, thereby expanding its application range. Microcapsules were prepared using a composite wall material consisting of chitosan (CS) and Arabic gum (AG), with tea tree essential oil (TTO) serving as the core material. The best CS-AG coated TTO microcapsules were prepared when the core–wall ratio was 1.2:1, the emulsifier concentration was 2%, the pH was 3, and the mass ratio of AG to CS (m_AG:m_CS) was 3:1. The m_AG:m_CS was identified as the most significant factor affecting the microcapsule yield and encapsulation rate. With the increase in m_AG:m_CS, the antimicrobial rate of the coating against Escherichia coli (E. coli) exhibited a trend of first rising and then falling, while the antimicrobial rate against Staphylococcus aureus (S. aureus) demonstrated a trend of first rising, then falling, and then rising again. The colour difference (ΔE) and gloss exhibited an overall downward trend, the light loss rate demonstrated a fluctuating upward trend, and the roughness exhibited a trend of first falling and then rising. The visible light band transmittance exhibited minimal variation, ranging from 86.43% to 92.76%. Microcapsule 14# (m_AG:m_CS = 3:1) demonstrated remarkable antimicrobial properties (E. coli 65.55%, S. aureus 73.29%), exceptional optical characteristics (light transmittance 92.12%, 60° gloss 24.0 GU), and notable flexibility (elongation at break 18.10%, modulus 0.10 GPa). The waterborne coating was modified by microcapsule technology, thus endowing the coating with antimicrobial properties and concomitantly broadening the scope of application of antimicrobial microcapsules. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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18 pages, 5263 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Novel Poly(butylene succinate-dilinoleic succinate) Films in Packaging Systems for Fresh Cut Chicory

by Szymon Macieja, Małgorzata Mizielińska, Mirosława El Fray and Artur Bartkowiak

Coatings 2025, 15(9), 1095; https://doi.org/10.3390/coatings15091095 - 18 Sep 2025

Viewed by 869

Abstract

Ready-to-eat products, such as mixed-cut leafy vegetables, require packaging that provides adequate mechanical protection, a barrier against UV radiation, gases, and water vapor, as well as microbiological safety. In this study, thin films made of polybutylene succinate (PBS) and poly (butylene succinate-dilinoleic succinate) [...] Read more.

Ready-to-eat products, such as mixed-cut leafy vegetables, require packaging that provides adequate mechanical protection, a barrier against UV radiation, gases, and water vapor, as well as microbiological safety. In this study, thin films made of polybutylene succinate (PBS) and poly (butylene succinate-dilinoleic succinate) (PBS-DLS) copolyester were prepared by casting a film-forming solution onto a glass plate and spreading it with a roller. These films were compared to commercial thin films made of oriented polypropylene (OPP). OPP films exhibited ten times higher tensile strength than PBS films (104.36 ± 10.03 MPa for OPP, 10.96 ± 0.68 MPa for PBS, and 6.36 ± 0.62 MPa for PBS-DLS). Incorporation of co-monomeric units of dilinoleic succinate (DLS) into PBS structure significantly improved elongation at break, increasing from 38.16% ± 12.36% for PBS to 132.30% ± 25.08% for PBS-DLS. However, commercial OPP had the highest elongation at break, reaching 231.84% ± 20.30%. OPP films exhibited the highest transparency in the visible light range but also in the UV range. In contrast, PBS and PBS-DLS films provided better UV radiation blocking. The films were used to create sachets by heat sealing, into which freshly cut chicory leaves were placed. The packaged product was stored under refrigerated conditions for 48 h and 120 h. While OPP and PBS-DLS films provided good protection against moisture loss in chicory, leaves packed in PBS sachets lost significant weight during storage. The packaged product contained considerable microbial contamination, but the type of packaging did not influence its reduction or increase. Ultimately, the PBS-DLS copolymer exhibited higher elongation at break and greater water vapor barrier properties than PBS. Protection against moisture loss in packaged chicory for PBS-DLS packaging was similar to that for commercial OPP. Despite their weaker mechanical properties, PBS-DLS films appear to be a promising alternative to OPP films for packaging fresh food products. Full article

(This article belongs to the Special Issue Preparation and Applications of Bio-Based Polymer Coatings)

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