Journal Description
Surfaces
Surfaces
is an international, peer-reviewed, open access journal on all aspects of surface and interface science published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, Inspec, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15.6 days after submission; acceptance to publication is undertaken in 3.8 days (median values for papers published in this journal in the first half of 2024).
- Journal Rank: CiteScore - Q2 (Materials Science (miscellaneous))
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.3 (2023);
5-Year Impact Factor:
2.6 (2023)
Latest Articles
Analysis, Assessment, and Mitigation of Stress Corrosion Cracking in Austenitic Stainless Steels in the Oil and Gas Sector: A Review
Surfaces 2024, 7(3), 589-642; https://doi.org/10.3390/surfaces7030040 - 16 Aug 2024
Abstract
This comprehensive review examines the phenomena of stress corrosion cracking (SCC) and chloride-induced stress corrosion cracking (Cl-SCC) in materials commonly used in the oil and gas industry, with a focus on austenitic stainless steels. The study reveals that SCC initiation can occur at
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This comprehensive review examines the phenomena of stress corrosion cracking (SCC) and chloride-induced stress corrosion cracking (Cl-SCC) in materials commonly used in the oil and gas industry, with a focus on austenitic stainless steels. The study reveals that SCC initiation can occur at temperatures as low as 20 °C, while Cl-SCC propagation rates significantly increase above 60 °C, reaching up to 0.1 mm/day in environments with high chloride concentrations. Experimental methods such as Slow Strain Rate Tests (SSRTs), Small Punch Tests (SPTs), and Constant-Load Tests (CLTs) were employed to quantify the impacts of temperature, chloride concentration, and pH on SCC susceptibility. The results highlight the critical role of these factors in determining the susceptibility of materials to SCC. The review emphasizes the importance of implementing various mitigation strategies to prevent SCC, including the use of corrosion-resistant alloys, protective coatings, cathodic protection, and corrosion inhibitors. Additionally, regular monitoring using advanced sensor technologies capable of detecting early signs of SCC is crucial for preventing the onset of SCC. The study concludes with practical recommendations for enhancing infrastructure resilience through meticulous material selection, comprehensive environmental monitoring, and proactive maintenance strategies, aimed at safeguarding operational integrity and ensuring environmental compliance. The review underscores the significance of considering the interplay between mechanical stresses and corrosive environments in the selection and application of materials in the oil and gas industry. Low pH levels and high temperatures facilitate the rapid progression of SCC, with experimental results indicating that stainless steel forms passive films with more defects under these conditions, reducing corrosion resistance. This interplay highlights the need for a comprehensive understanding of the complex interactions between materials, environments, and mechanical stresses to ensure the long-term integrity of critical infrastructure.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
Study on the Lubrication Performance of Graphene-Based Polyphosphate Lubricants in High-Temperature Steel–Steel Friction Pair
by
Kaifu Mi, Qingqing Ding, Xiangru Xu, Yu Lei, Juncheng Wang and Ning Kong
Surfaces 2024, 7(3), 571-588; https://doi.org/10.3390/surfaces7030039 - 11 Aug 2024
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In the study, a hybrid lubricant was prepared by introducing graphene into a polyphosphate lubricant. In the tribological test of a steel/steel friction pair at the high temperature of 800 °C, the addition of a small proportion of graphene significantly enhances the lubrication
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In the study, a hybrid lubricant was prepared by introducing graphene into a polyphosphate lubricant. In the tribological test of a steel/steel friction pair at the high temperature of 800 °C, the addition of a small proportion of graphene significantly enhances the lubrication performance of polyphosphate at elevated temperatures. The coefficient of friction and the wear were obviously held down while the surface quality of the high-temperature friction pair was enhanced effectively with the graphene-strengthened polyphosphate lubricant, compared with the dry sliding condition. Through scanning electron microscopy and Raman spectroscopy analysis, the formation mechanism of tribofilm and the antiwear performance of the hybrid lubricant are further explained. This lubricant effectively combines the advantages of both; the combination of polyphosphate melted at elevated temperature with graphene and metal surfaces ensures the self-sealing of the friction contact area and brings better high-temperature oxidation resistance. At the same time, the presence of graphene provides excellent strength to the friction film and ensures the anti-wear and wear-resistant performance of the lubricant at high temperatures.
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Open AccessArticle
Evaluation of Photocatalytic Hydrogen Evolution in Zr-Doped TiO2 Thin Films
by
Luis F. Garay-Rodríguez, M. R. Alfaro Cruz, Julio González-Ibarra, Leticia M. Torres-Martínez and Jin Hyeok Kim
Surfaces 2024, 7(3), 560-570; https://doi.org/10.3390/surfaces7030038 - 9 Aug 2024
Abstract
Doping titanium dioxide has become a strategy for enhancing its properties and reducing its recombination issues, with the aim of increasing its efficiency in photocatalytic processes. In this context, this work studied its deposition over glass substrates using a sol–gel dip coating methodology.
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Doping titanium dioxide has become a strategy for enhancing its properties and reducing its recombination issues, with the aim of increasing its efficiency in photocatalytic processes. In this context, this work studied its deposition over glass substrates using a sol–gel dip coating methodology. The effect of doping TiO2 with Zirconium cations in low molar concentrations (0.01, 0.05, 0.1%) in terms of its structural and optical properties was evaluated. The structural characterization confirmed the formation of amorphous thin films with Zr introduced into the TiO2 cell (confirmed by XPS characterization), in addition to increasing and defining the formed particles and their size slightly. These changes resulted in a decrease in the transmittance percentage and their energy band gap. Otherwise, their photocatalytic properties were evaluated in hydrogen production using ethanol as a sacrificial agent and UV irradiation. The hydrogen evolution increased as a function of the Zr doping, the sample with the largest Zr concentration (0.1% mol) being the most efficient, evolving 38.6 mmolcm−2 of this gas. Zr doping favored the formation of defects in TiO2, being responsible for this enhancement in photoactivity.
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(This article belongs to the Special Issue Recent Advances on Catalytic Surfaces and Interfaces)
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Open AccessArticle
Applicability of Fluorine Gas Surface Treatment to Control Liquid Sodium Wettability
by
Masanari Namie, Jun-ichi Saito, Asuka Ikeda, Ryotaro Oka and Jae-Ho Kim
Surfaces 2024, 7(3), 550-559; https://doi.org/10.3390/surfaces7030037 - 9 Aug 2024
Abstract
The iron (Fe) specimens selected as the substrate metal for this study were surface-treated using fluorine gas, and their wettability with liquid sodium (Na) was evaluated using the sliding angle. Additionally, the surface morphology and binding state were analyzed, and the applicability of
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The iron (Fe) specimens selected as the substrate metal for this study were surface-treated using fluorine gas, and their wettability with liquid sodium (Na) was evaluated using the sliding angle. Additionally, the surface morphology and binding state were analyzed, and the applicability of wettability control with liquid sodium by fluorination was discussed using the analysis results. Fluorination formed a fluoride layer comprising FeF2 and FeF3 bonds on the iron surface. The composition of the fluoride layer varied, depending on the treatment conditions. The surface of the specimen that contains a lot of FeF3 bonds had a small sliding angle for the liquid sodium droplet and was harder to wet than the untreated specimen. In contrast, the surface of the specimen that contains a lot of FeF2 bonds had a large sliding angle for the liquid sodium droplet and was easier to wet than the untreated specimen. These results indicate that fluorination is an effective surface modification technique that can be applied to control the wettability of iron with liquid sodium.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessFeature PaperArticle
Sustainable Production of Biosurfactant Grown in Medium with Industrial Waste and Use for Removal of Oil from Soil and Seawater
by
Bruna G. A. Lima, Júlio C. V. Santos, Renata R. Silva, Maria Catarina F. Caldas, Hugo M. Meira, Raquel D. Rufino, Leonie A. Sarubbo and Juliana M. Luna
Surfaces 2024, 7(3), 537-549; https://doi.org/10.3390/surfaces7030036 - 1 Aug 2024
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Biosurfactants are amphipathic molecules with considerable potential for application in different industries due to their biochemical characteristics, low toxicity as well as greater biodegradability and stability compared to chemical surfactants when submitted to adverse environmental conditions. The aim of the present study was
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Biosurfactants are amphipathic molecules with considerable potential for application in different industries due to their biochemical characteristics, low toxicity as well as greater biodegradability and stability compared to chemical surfactants when submitted to adverse environmental conditions. The aim of the present study was to investigate the production of a biosurfactant by Candida lipolytica UCP 0988 grown in a medium containing 4.0% molasses, 2.5% used soybean frying oil, and 2.5% corn steep liquor for 144 h at 200 rpm. The biosurfactant was characterized; its stability and toxicity were investigated, and the compound was applied in oil removal tests. In the C. lipolytica growth and biosurfactant production studies, the surface tension of the medium was reduced from 72 mN/m to 25 mN/m, the critical micellar concentration (CMC) was 0.5 g/L (w/v), and the yield was 12 g/L. Tests under extreme conditions of temperature, pH, and NaCl indicated the stability of the biosurfactant. Fourier-transform infrared and nuclear magnetic resonance spectroscopy of the chemical structure of the purified biosurfactant suggested that the biosurfactant is a glycolipid. The anionic biosurfactant exhibited no toxicity to the microcrustacean Artemia salina or vegetable seeds (Brassica oleracea). Dispersion tests in seawater demonstrated 100% efficiency of the biomolecule against motor oil. The biosurfactant was efficient at removing oil from sand in static and kinetic tests at concentrations of ½ CMC (0.25 g/L), CMC (0.5 g/L), and 2 × CMC (1.0 g/L), with removal rates of 70 to 96%, whereas the synthetic surfactants tested removed only 10 to 18% of the oil. Based on the findings, the biosurfactant analyzed has considerable potential for the remediation of contaminated coastal and marine environments due to oil spills.
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Open AccessArticle
Direct Visualization of Organometallic Intermediates on Cu(111) with Bond-Resolving Non-Contact Atomic Force Microscopy
by
Xiaoyu Hao, Yan Li, Hongyan Ji, Tingting Wang, Haolong Fan, Quanzhen Zhang, Huixia Yang, Liwei Liu, Teng Zhang and Yeliang Wang
Surfaces 2024, 7(3), 529-536; https://doi.org/10.3390/surfaces7030035 - 1 Aug 2024
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In this study, we investigated the surface-confined coupling reactions of 1,8-dibromobiphenylene (BPBr2) on Cu(111) to elucidate the details of the organometallic intermediates via Ullmann reactions. We used scanning tunneling microscopy (STM) to characterize the resulting organometallic intermediates. Moreover, submolecular resolution of
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In this study, we investigated the surface-confined coupling reactions of 1,8-dibromobiphenylene (BPBr2) on Cu(111) to elucidate the details of the organometallic intermediates via Ullmann reactions. We used scanning tunneling microscopy (STM) to characterize the resulting organometallic intermediates. Moreover, submolecular resolution of the non-contact atomic force microscopy (nc-AFM) qPlus technique enables the bond-resolving within the organometallic dimer product. Our findings reveal the debromination of BPBr2 on Cu(111), leading to the formation of an organometallic dimer intermediate at room temperature. Through nc-AFM measurements, we confirm and visualize the formation of the C-Cu-C bond. These insights enhance our understanding of Ullmann reaction and hold potential implications for the design of novel two-dimensional electronic devices.
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Open AccessArticle
High-Gas-Barrier and Biodegradable PPC-P/PBAT Composite Films Coated by Poly(vinyl alcohol)/borax Complexes
by
Jiangtao Deng, Shuangshuang Yue, Min Xiao, Sheng Huang, Shuanjin Wang, Dongmei Han and Yuezhong Meng
Surfaces 2024, 7(3), 517-528; https://doi.org/10.3390/surfaces7030034 - 1 Aug 2024
Abstract
Degradable and high-barrier plastic packaging materials draw more attention with the development of a social economy and the demands of environmental protection. In this study, poly(propylene carbonate phthalate) (PPC-P) and poly(butylene adipate-co-terephthalate) (PBAT) blends with different ratios were designed and prepared, marked as
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Degradable and high-barrier plastic packaging materials draw more attention with the development of a social economy and the demands of environmental protection. In this study, poly(propylene carbonate phthalate) (PPC-P) and poly(butylene adipate-co-terephthalate) (PBAT) blends with different ratios were designed and prepared, marked as PPC-P/PBAT. Chain extenders were introduced into the blends, and the mechanical properties, thermal properties, and barrier properties of the composites were studied. The 75PPC-P/PBAT with 2% extenders represent the best performance. The addition of the chain extender has significantly improved the thermal stability and tensile elongation of PPC-P/PBAT. On this basis, the PPC-P/PBAT composite film was coated with PVA and borax using the dipping and pulling method. The oxygen barrier properties have been further improved for the composite film with a coating layer. Considering the characteristics of biodegradability and a high-barrier property, the 75PPC-P/PBAT/2MDI@Gly blend coated with 2 wt% PVA and 3 wt% borax exhibits potential as a superior food/pharmaceutical plastic packaging material with excellent tensile and barrier properties.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
Enhancing Water Condensation on Hybrid Surfaces by Optimizing Wettability Contrast
by
Do-Thuy Chi and Thanh-Binh Nguyen
Surfaces 2024, 7(3), 508-516; https://doi.org/10.3390/surfaces7030033 - 24 Jul 2024
Abstract
This study uses a hybrid concept to propose an optimal textured surface morphology for enhancing water condensation. The natural phenomenon-inspired morphology, which combined different degrees of wettability presented on the surface, documented their advantage in water harvesting compared to untreated surfaces. These superiorities
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This study uses a hybrid concept to propose an optimal textured surface morphology for enhancing water condensation. The natural phenomenon-inspired morphology, which combined different degrees of wettability presented on the surface, documented their advantage in water harvesting compared to untreated surfaces. These superiorities might be explained by the appropriate combination of nucleation and water-driven ability facilitated by the superhydrophobic surrounding area. The uniform condensed droplets are effectively agglomerated to achieve the critical size. The best combination was found on a superhydrophobic-hydrophilic hybrid sample that improved water collection efficiency by up to 50% compared to bare Al. Condensation performance also illustrated an interesting tendency that revealed the great contribution of wettability on hydrophilic dots and the water-driven ability of the high-hydrophobicity area. The results were supported by a theoretical model which predicts the critical volume of a single droplet before it has departed from the surface. The findings reveal a good level of agreement between theory and real-time measurement, demonstrating the potential of combinations of hybrid samples to induce water collection efficiency.
Full article
(This article belongs to the Special Issue Advancements in Surface Engineering for Metallic Alloys)
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Open AccessArticle
Eliminating Manifold Pharmaceutical Pollutants with Carbon Nanoparticles Driven via a Short-Duration Ball-Milling Process
by
Tarig G. Ibrahim, Rasmiah S. Almufarij, Babiker Y. Abdulkhair and Mohamed E. Abd Elaziz
Surfaces 2024, 7(3), 493-507; https://doi.org/10.3390/surfaces7030032 - 18 Jul 2024
Abstract
One of the major problems facing humanity in all parts of the world is water pollution. Since carbon nanoparticles (CPs) are known for their excellent absorbability, this study explored preparing CPs via a facilitated ball-milling protocol. Four CP products were prepared with the
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One of the major problems facing humanity in all parts of the world is water pollution. Since carbon nanoparticles (CPs) are known for their excellent absorbability, this study explored preparing CPs via a facilitated ball-milling protocol. Four CP products were prepared with the friction enhancer being variated, typically 0-CPs, 2.5-CPs, 5-CPs, and 10-CPs. The four sorbents were characterized using TEM, EDX, XRD, BET, and FTIR methods. The 0-CPs, 2.5-CPs, 5-CPs, and 10-CPs possessed a BET surface area of 113, 139, 105, and 98.5 m2 g−1, respectively, and showed a sorption capacity of 55.6, 147.0, 65.8, and 24.6 mg g−1 when tested with chlorohexidine (CH). Therefore, the 2.5-CPs were selected as the best sorbents among the prepared nanomaterials and employed for further sorption investigations. The CH sorption on the 2.5-CPs followed the pseudo-second-order, and the liquid–film diffusion controlled the CH sorption onto the 2.5-CPs. The Langmuir isotherm model was followed, and the Dubinin–Radushkevich energy was 3.0 kJ mole−1, indicating a physisorption process. The thermodynamic outputs suggested that CH sorption by 2.5-CPs was favorable. Furthermore, the 2.5-CPs sorbent was tested for treating water samples contaminated with 20 mg L−1 of ciprofloxacin, dextromethorphan, guaifenesin, metronidazole, ibuprofen, chlorzoxazone, chlorpheniramine malate paracetamol, and hydro-chlorothiazide. The 2.5-CPs showed an average removal efficiency of 94.1% with a removal range of 92.1% to 98.3% and a 2.21 standard deviation value.
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(This article belongs to the Collection Featured Articles for Surfaces)
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Open AccessArticle
Application of High-Surface Tension and Hygroscopic Ionic Liquid-Infused Nanostructured SiO2 Surfaces for Reversible/Repeatable Anti-Fogging Treatment
by
Satoshi Nakamura, Jerred Wassgren, Sayaka Sugie and Atsushi Hozumi
Surfaces 2024, 7(3), 482-492; https://doi.org/10.3390/surfaces7030031 - 2 Jul 2024
Abstract
Anti-fogging coatings/surfaces have attracted much attention lately because of their practical applications in a wide variety of engineering fields. In this study, we successfully developed transparent anti-fogging surfaces using a non-volatile and hygroscopic ionic liquid (IL), bis(hydroxyethyl)dimethylammonium methanesulfonate ([BHEDMA][MeSO3]), with a
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Anti-fogging coatings/surfaces have attracted much attention lately because of their practical applications in a wide variety of engineering fields. In this study, we successfully developed transparent anti-fogging surfaces using a non-volatile and hygroscopic ionic liquid (IL), bis(hydroxyethyl)dimethylammonium methanesulfonate ([BHEDMA][MeSO3]), with a high surface tension (HST, 66.4 mN/m). To prepare these surfaces, a layer of highly transparent, superhydrophilic silica (SiO2) nano-frameworks (SNFs) was first prepared on a glass slide using candle soot particles and the subsequent chemisorption of tetraethoxysilane (TEOS). This particulate layer of SNFs was then used as the support for the preparation of the [BHEDMA][MeSO3] layer. The resulting IL-infused SNF-covered glass slide was highly transparent, superhydrophilic, hygroscopic, and had self-healing and reasonable reversible/repeatable anti-fogging/frosting properties. This IL-infused sample surface kept its excellent anti-fogging performance in air for more than 8 weeks due to the IL’s non-volatile, HST, and hygroscopic nature. In addition, even if the water absorption limit of [BHEDMA][MeSO3] was reached, the anti-fogging properties could be fully restored reversibly/repeatably by simply leaving the samples in air for several tens of minutes or heating them at 100 °C for a few minutes to remove the absorbed water. Our IL-based anti-fogging surfaces showed substantial improvement in their abilities to prevent fogging when compared to other dry/wet (super)hydrophobic/(super)hydrophilic surfaces having different surface geometries and chemistries.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
Size-Dependence of the Electrochemical Activity of Platinum Particles in the 1 to 2 Nanometer Range
by
Hiroshi Yano and Kouta Iwasaki
Surfaces 2024, 7(3), 472-481; https://doi.org/10.3390/surfaces7030030 - 2 Jul 2024
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Monodisperse Pt nanoparticles supported on carbon (Pt/C) were prepared via an impregnation method. By changing the concentration of the platinum precursor in the initial reagent mixture, the average particle size (d) could be controlled to within a narrow range of less
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Monodisperse Pt nanoparticles supported on carbon (Pt/C) were prepared via an impregnation method. By changing the concentration of the platinum precursor in the initial reagent mixture, the average particle size (d) could be controlled to within a narrow range of less than 2 nm. The specific activity (SA) of these materials, when applied to the oxygen reduction reaction (ORR), increased rapidly with d in the range below 1.8 nm, with a maximum SA at d = 1.3 nm. This value is approximately four times that of a commercial Pt/CB catalyst. The electrochemical active area, ECAA (electrochemical surface area (ECSA)/specific surface area (SSA) × 100), decreased drastically from 100% with decreases in d below 1.3 nm. In this study, we present a correlation between SA and ECAA as a means of determining the appropriate d for polymer electrolyte fuel cells (PEFCs) and propose an optimal size.
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Open AccessArticle
Preparation and Printing Performance of Visible Light Photochromic Paper Based on PMoA-PWA/ZnO/PVP Composite
by
Wanqing Zhao, Hongmei Zhao, Wei Feng and Honggang Zhao
Surfaces 2024, 7(3), 460-471; https://doi.org/10.3390/surfaces7030029 - 1 Jul 2024
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The recyclable paper based on photochromic materials not only reduces the pollution in the paper manufacture process, but also reduces the pollution caused by the use of ink, which receives wide attention. In this paper, a series of phosphomolybdic acid–phosphotungstic acid/ZnO/polyvinylpyrrolidone (PMoA-PWA/ZnO/PVP) hybrid
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The recyclable paper based on photochromic materials not only reduces the pollution in the paper manufacture process, but also reduces the pollution caused by the use of ink, which receives wide attention. In this paper, a series of phosphomolybdic acid–phosphotungstic acid/ZnO/polyvinylpyrrolidone (PMoA-PWA/ZnO/PVP) hybrid films, which had different ratio of PMoA/PWA, was prepared by the ultrasonic composite method. The results indicated that the hybrid film prepared when the ratio of PMoA to PWA was 3 had the best photochromic performance. In this system, ZnO was the photosensitizer, while PMoA/PWA was the chromophore. The photochromic mechanism of the PMoA-PWA/ZnO/PVP hybrid film was based on the photogenerated electron transfer mechanism. ZnO generated photoelectron under the excitation of visible light, then PMoA and PWA obtained the photoelectron and produced photoreduction reaction to generate heteropolyblue. The visible light photochromic paper was prepared by loaded PMoA-PWA/ZnO/PVP hybrid film (A3) on A4 paper. Application tests showed that the prepared paper had extremely stable, excellent and reversible visible light photochromic properties, whether it was printing patterns or words, and could replace ordinary paper to realize the reuse of paper.
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Open AccessReview
Catalytically Active Materials Visualized by Scanning Photoelectron Spectro-Microscopy
by
Matteo Amati, Lada V. Yashina, Philipp Winkler, Kevin Sparwasser, Zygmunt Milosz, Günther Rupprechter and Luca Gregoratti
Surfaces 2024, 7(3), 442-459; https://doi.org/10.3390/surfaces7030028 - 26 Jun 2024
Abstract
Modern catalysts are complex systems whose performance depends both on space and time domains and, most importantly, on the operational environment. As a direct consequence, understanding their functionalities requires sophisticated techniques and tools for measurement and simulation, addressing the proper spatial and temporal
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Modern catalysts are complex systems whose performance depends both on space and time domains and, most importantly, on the operational environment. As a direct consequence, understanding their functionalities requires sophisticated techniques and tools for measurement and simulation, addressing the proper spatial and temporal scale and being capable of mimicking the working conditions of every single component, such as catalyst supports, electrodes, electrolytes, as well as of the entire assembly, e.g., in the case of fuel cells or batteries. Scanning photoelectron spectro-microscopy (SPEM) is one of the approaches that allow combining X-ray photoelectron spectroscopy with sub-micron spatial resolution; in particular, the SPEM hosted at the ESCA Microscopy beamline at Elettra has been upgraded to conduct in situ and operando experiments. Three different case studies are presented to illustrate the capabilities of the SPEM in the investigation of catalytic materials in different conditions and processes.
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(This article belongs to the Special Issue In Situ and Operando Catalyst Characterization)
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Open AccessArticle
Interactions between Cetyltrimethylammonium Bromide Modified Cellulose Nanocrystals and Surfaces: An Ellipsometric Study
by
Xiaoyu Gong, Md Farhad Ismail and Yaman Boluk
Surfaces 2024, 7(2), 428-441; https://doi.org/10.3390/surfaces7020027 - 19 Jun 2024
Abstract
The tailoring of the surface properties of cellulose nanocrystals (CNCs) to meet various requirements in environmental, food, and material areas has always been of great interest. In this study, the surface chemistry of CNCs was noncovalently modified by cetyltrimethylammonium bromide (CTAB), followed by
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The tailoring of the surface properties of cellulose nanocrystals (CNCs) to meet various requirements in environmental, food, and material areas has always been of great interest. In this study, the surface chemistry of CNCs was noncovalently modified by cetyltrimethylammonium bromide (CTAB), followed by characterizations and an investigation into its application as a coating material for interfacial interaction over various substrates. Due to the CTAB modification, the surface charge of the CNCs was neutralized, resulting in an increased size of each nanocrystal at the aqueous status and the aggregated microfibers when dried up. The CTAB modification not only decreased the crystallinity of the samples from 48.57% to 9.12%, but also reasonably hydrophobized the CNCs and decreased their total surface energy. Finally, the adsorption behavior of the CNCs and CTAB-CNCs over nonionic, anionic, and cationic polymers was investigated by ellipsometry. Based on the thickness of the CNC and CTAB-CNC layers over 2-Hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), and polyethyleneimine (PEI), we proposed that the adsorption behavior was overall influenced by electrostatic interaction, hydrogen bonding, and van der Waals forces, and the thickness of the adsorbed layers could be impacted by both the surface charge and the size of the crystals.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
General Method for Predicting Interface Bonding at Various Oxide–Metal Interfaces
by
Michiko Yoshitake
Surfaces 2024, 7(2), 414-427; https://doi.org/10.3390/surfaces7020026 - 3 Jun 2024
Abstract
Interface termination bonding between metal oxide and metals is discussed from the viewpoint of thermodynamics. The method of interface termination prediction proposed by the authors for Al2O3–metal and ZnO–metal interfaces is extended to a general interface between metal-oxide and
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Interface termination bonding between metal oxide and metals is discussed from the viewpoint of thermodynamics. The method of interface termination prediction proposed by the authors for Al2O3–metal and ZnO–metal interfaces is extended to a general interface between metal-oxide and metals. The extension of the prediction method to the interface between metal oxides and elemental semiconductors is also discussed. Information on interface bonding was extracted by carefully examining the experimental results and first-principles calculations in the references. The extracted information on interface bonding from references is compared with the results obtained via the proposed prediction method. It is demonstrated that interface termination bonding can be predicted by extending the method to oxide–metal interfaces in general, when there is no interface reaction such as the reduction of oxide, oxidation of metal, or mixed oxide formation. The method uses only basic quantities of pure elements and the formation enthalpy of oxides. Therefore, it can be applied to most of the metals (including elemental semiconductors) in the periodic table and metal oxides with one stable valence. The method is implemented as a software, “InterChemBond”, and can be used free of charge.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
Adsorption of Gadolinium Bisphthalocyanine on Atomically Flat Surfaces: Comparison of Graphene and Hexagonal Boron Nitride from DFT Calculations
by
Vladimir A. Basiuk and Elena V. Basiuk
Surfaces 2024, 7(2), 404-413; https://doi.org/10.3390/surfaces7020025 - 1 Jun 2024
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We studied the noncovalent interactions of gadolinium bisphthalocyanine (GdPc2) with cluster models for graphene and hexagonal boron nitride (hBN) of variable size by using the PBE functional of the generalized gradient approximation in conjunction with Grimme’s dispersion correction and
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We studied the noncovalent interactions of gadolinium bisphthalocyanine (GdPc2) with cluster models for graphene and hexagonal boron nitride (hBN) of variable size by using the PBE functional of the generalized gradient approximation in conjunction with Grimme’s dispersion correction and a DND double numerical basis set (that is, PBE-D2/DND). We found that in terms of the bonding strength, changes in the Gd-N bond lengths, the charge and spin of the Gd central ion, and the spin of the GdPc2 molecule, the behaviors of the graphene- and hBN-based model systems are rather similar. As expected, when increasing the size of the graphene and hBN cluster models, the strength of the interaction with GdPc2 increases, in which the bonding with the hBN models is usually stronger by a few kcal/mol. One of the main questions addressed in the present work was whether a change in the antiferromagnetic spin alignment to a ferromagnetic one, which is typical for GdPc2, is (at least theoretically) possible, as it has been observed previously for a number of graphene models when a smaller basis set DN was employed. We found that the use of a larger DND basis set dramatically reduces the occurrence of ferromagnetic adsorption complexes but does not exclude this possibility completely.
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Open AccessReview
The Use of Plant Extracts as Green Corrosion Inhibitors: A Review
by
Milad Sheydaei
Surfaces 2024, 7(2), 380-403; https://doi.org/10.3390/surfaces7020024 - 1 Jun 2024
Cited by 2
Abstract
The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a
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The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a good choice among other protection techniques because of their good efficiency, the toxicity of many of them causes environmental problems, and, due to the change in the laws on the use of chemicals, many of them are no longer allowed. Hence, during the past years, research on green corrosion inhibitors (GCIs) increased and very favorable results were obtained, and now they are very popular. It can be said that biodegradability and easy preparation are their most important factors. Meanwhile, the use of plants, especially their extracts, has been studied a lot. Plant extracts contain compounds that have anti-corrosion properties. In this review, the use of plants as GCIs is investigated, focusing on recent advances in their use. Also, the phenomenon of corrosion, corrosion protection (including coatings, nanoparticles, and chemical inhibitors), and other GCIs are briefly reviewed.
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(This article belongs to the Special Issue Surface Modification and Coating to Improve Properties of Various Materials)
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Open AccessArticle
Optical Characteristics of Directly Deposited Gold Nanoparticle Films
by
Jordi Sancho Parramon, Tilen Švarc, Peter Majerič, Žiga Jelen and Rebeka Rudolf
Surfaces 2024, 7(2), 369-379; https://doi.org/10.3390/surfaces7020023 - 27 May 2024
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The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4
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The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4 h. The morphological characterisation of the deposited films showed that the size of the first deposited AuNPs was between 10 and 30 nm, while, with a longer duration of the deposition process, larger clusters of AuNPs grew by coalescence and aggregation. The prepared layers were characterised optically with Ultraviolet–visible spectroscopy (UV–vis) and ellipsometry. The ellipsometric measurements showed an increasingly denser and thicker effective thickness of the AuNP layers. The extinction spectra displayed a clear local surface plasmonic resonance (LSPR) signature (peak 520–540 nm), indicating the presence of isolated particles in all the samples. For all AuNP layers, the imaginary part of the parallel and perpendicular components of the anisotropic dielectric function was dominated by a central peak at around 2.2 eV, corresponding to the LSPR of isolated particles, and a high-energy shoulder due to Au interband transitions. It was shown that, as the density of particles increased, the extinction cross-section grew over the whole spectral range where measurements are taken. Thus, the response can be explained with an enhanced electromagnetic response between the AuNPs that can be connected to the increase in particle density, but also by the formation of clusters and irregular structures.
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Open AccessArticle
Formation of Organic Monolayers on KF-Etched Si Surfaces
by
Tiexin Li, Zane Datson and Nadim Darwish
Surfaces 2024, 7(2), 358-368; https://doi.org/10.3390/surfaces7020022 - 10 May 2024
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Silicon is the most commonly used material in the microelectronics industry, due to its inherent advantages of high natural abundance, low cost, and high purity, coupled with the chemical and electrical stability at the interface with its oxide. For molecular electronics applications, oxide-free
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Silicon is the most commonly used material in the microelectronics industry, due to its inherent advantages of high natural abundance, low cost, and high purity, coupled with the chemical and electrical stability at the interface with its oxide. For molecular electronics applications, oxide-free Si surfaces are widely used because of the relative ease of removing the oxide (SiOx) by chemical means, yielding a surface which forms strong covalent bonds with a wide range of chemical functional groups; another advantage is that these surfaces remain oxide-free in the absence of oxidising agents. Standard procedures require the use of either HF, NH4F, or a mixture of both as the etching solution; however, these two chemicals are highly corrosive and toxic, posing a significant risk to the experimentalist. Here, we report that for silicon wafers etched by using potassium fluoride, a less toxic chemical, the resulting surface is free of oxides and can be functionalized by self-assembled monolayers of 1,8-nonadiyne. To demonstrate this, Si/SiOx wafers were etched by using either KF or NH4F, followed by hydrosilylation with 1,8-nonadiyne and a click reaction of the terminal alkyne with azidomethylferrocene. The surface coverages and electron transfer kinetics of the ferrocene-terminated KF-etched surfaces are comparable to those formed by acidic fluoride etching procedures. This is the first study comparing the differences between surfaces functionalized by self-assembled monolayers of 1,8-nonadiyne which were etched by KF and NH4F. KF could be used as a replacement chemical for etching silicon wafers when a less corrosive and toxic chemical is required.
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Open AccessArticle
Evaluation of the Feasibility of the Prediction of the Surface Morphologiesof AWJ-Milled Pockets by Statistical Methods Based on Multiple Roughness Indicators
by
Nikolaos E. Karkalos, Muthuramalingam Thangaraj and Panagiotis Karmiris-Obratański
Surfaces 2024, 7(2), 340-357; https://doi.org/10.3390/surfaces7020021 - 10 May 2024
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Improvement of the surface quality of machined parts is essential in order to avoid excessive and costly post-processing. Although non-conventional processes can efficiently carry out the machining of difficult-to-cut materials with high productivity, they may also, for various reasons, be related to increased
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Improvement of the surface quality of machined parts is essential in order to avoid excessive and costly post-processing. Although non-conventional processes can efficiently carry out the machining of difficult-to-cut materials with high productivity, they may also, for various reasons, be related to increased surface roughness. In order to optimize the surface quality of generated surfaces in a reliable way, surface profiles obtained during these processes must be adequately modeled. However, given that most studies have focused on Ra or Rz indicators or are based on the assumption of a normal distribution for the profile heights, relevant models cannot accurately represent the surface characteristics that exist in a real machined surface with a high degree of accuracy. Thus, in the present study, a new modeling approach based on the use of a statistical probability distribution for the surface profile height is proposed. After six different distributions were evaluated on the basis of a three-stage procedure involving different roughness indicators pertaining to the abrasive waterjet (AWJ) milling of pockets, it was found that, although it is not possible to model the nominal values of every roughness parameter simultaneously, in several cases, it is possible to approximate the values of critical indicators such as Ra, Rz, Rsk, Rku and Rp/Rv ratio by Weibull distribution with a sufficient degree of accuracy.
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