Surfaces

17 pages, 389 KB

Open AccessPerspective

The Characteristic Function as a Unifying Framework for Linear Response in Surface Diffusion

by Elena Esther Torres-Miyares and Salvador Miret-Artés

Surfaces 2026, 9(3), 72; https://doi.org/10.3390/surfaces9030072 - 7 Aug 2026

In this short perspective, we analyze the different linear response functions relevant to surface diffusion as studied by helium atom scattering, organizing them around a single object: the intermediate scattering function (ISF), which is also a characteristic function (CF) in the sense of [...] Read more.

In this short perspective, we analyze the different linear response functions relevant to surface diffusion as studied by helium atom scattering, organizing them around a single object: the intermediate scattering function (ISF), which is also a characteristic function (CF) in the sense of probability theory. This organizing role of the CF is, to our knowledge, not made explicit elsewhere in the surface-diffusion literature. The exponential time dependence of the ISF observed in the diffusive regime (times much greater than the inverse of the friction coefficient) is a special case of the classical continuous-time random walk (CTRW) theory. Special emphasis is placed on this regime where quantum features of the diffusion process are washed out. We show how the entire hierarchy of response functions—the after-effect function, the generalized susceptibility, the relaxation function, and the Green function—can be written directly in terms of the time moments of the ISF at

t = 0

. Moreover, the standard Pauli master equation and the Chudley–Elliott (CE) jump model follow as particular lattice realizations of a general compound-Poisson process. The extension to finite surface coverage is discussed within the interacting single adsorbate (ISA) model. Full article

(This article belongs to the Collection Featured Articles for Surfaces)

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17 pages, 41389 KB

Open AccessArticle

Impedance Spectroscopy of Hybrid Structures Based on Nanostructured Porous Silicon and Porous Hierarchical Nickel Oxide Nanoparticles

by Kamilya Khalugarova, Yulia M. Spivak, Anton A. Bobkov, Dmitriy A. Kozodaev and Vyacheslav A. Moshnikov

Surfaces 2026, 9(3), 71; https://doi.org/10.3390/surfaces9030071 - 4 Aug 2026

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Abstract

A technological approach to the formation of a 3D nanocomposition material based on hierarchical porous nickel oxide nanoparticles incorporated into porous silicon with a dendritic porous structure is proposed. Porous silicon was used as a 3D porous template, in the presence of which [...] Read more.

A technological approach to the formation of a 3D nanocomposition material based on hierarchical porous nickel oxide nanoparticles incorporated into porous silicon with a dendritic porous structure is proposed. Porous silicon was used as a 3D porous template, in the presence of which porous hierarchical nickel oxide nanoparticles were synthesized using a “green” synthesis method followed by annealing in an oxygen-containing atmosphere. The resulting materials were characterized using scanning electron microscopy, transmission electron microscopy, X-ray spectral microanalysis, X-ray diffraction, and the BET method. The potential of a developed composition based on porous hierarchical nickel and silicon oxide nanoparticles to enhance the sensitivity of adsorption gas sensors was assessed using impedance spectroscopy in the presence of a probe gas (isopropanol). Gas sensitivity measurements were conducted at room and elevated temperatures in the frequency range from 100 Hz to 500 kHz. Differences in the dependences of the real part of impedance on the imaginary part were revealed for the porNiO-porSi composition in Nyquist coordinates. The results are discussed in terms of percolation theory and fractal organization. Full article

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24 pages, 3491 KB

Open AccessArticle

Ultra-Short Laser Micro- and Nanopatterning of Polyethylene Terephthalate (PET): Towards Surface Topographies for Antibacterial and Self-Cleaning Applications

by Liliya Angelova, Aleksandra Zhelyazkova, Laura L. E. Mears, Daniela Miano, Richard van Nieuwendhowen and Albena Daskalova

Surfaces 2026, 9(3), 70; https://doi.org/10.3390/surfaces9030070 - 31 Jul 2026

Viewed by 189

Abstract

Antimicrobial resistance is a critical global challenge that necessitates the development of durable, material-based strategies to limit pathogen survival and transmission. Conventional cleaning and disinfection methods only provide transient protection due to rapid surface re-contamination. This study investigates the fabrication of polyethylene terephthalate [...] Read more.

Antimicrobial resistance is a critical global challenge that necessitates the development of durable, material-based strategies to limit pathogen survival and transmission. Conventional cleaning and disinfection methods only provide transient protection due to rapid surface re-contamination. This study investigates the fabrication of polyethylene terephthalate (PET) surfaces designed for antibacterial applications via femtosecond laser-induced micro- and nanostructuring. Surface texturing was performed using a Ti:sapphire femtosecond laser (wavelength λ = 800 nm, pulse duration τ = 70 fs) at peak laser fluences (F) of 2.04 J/cm² and 4.08 J/cm², generating hierarchical surface textures with controlled morphology, spacing, and geometry through ultrafast, non-contact laser processing while preserving the bulk properties of PET. The resulting patterns, including parallel and intersecting microchannels decorated with laser-induced nanostructures, enabled tunable surface roughness and wettability, with water contact angles ranging from 33.21° to 118.2°. Comprehensive surface characterization, including morphological, topographical, and wettability analyses, was performed to establish structure–property relationships associated with previously reported antibacterial surface design principles. However, direct antibacterial performance was not evaluated in the present study and will be the subject of future investigations. In addition, the durability of the laser-structured PET was evaluated under simulated real-life conditions, including thermal cycling, ultraviolet exposure, abrasion, chemical resistance, and dust contamination. The structured surfaces demonstrated high structural and functional stability following environmental testing. The results indicate that the laser-induced surface modifications remain stable under conditions representative of prolonged practical use, supporting their potential long-term applicability for antibacterial and self-cleaning PET surfaces. Full article

(This article belongs to the Special Issue Surface Engineering for Biomedical Applications)

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22 pages, 14462 KB

Open AccessArticle

Picosecond Laser Treatment of Cu-Doped TiO₂ Coatings: Effects on Mechanical Resistance, Electrochemical Behaviour, and Antibacterial Activity

by Elena Zheleva, Maria P. Nikolova, Iliyan Tzvetkov, Stefan Valkov, Nikolay Nedyalkov, Iliana Kostova, Andreana Andreeva, Rosen Nikov, Rumen Nikov, Edmon Lazarov, Maria Ormanova, Stanka Damyanova and Imants Adijans

Surfaces 2026, 9(3), 69; https://doi.org/10.3390/surfaces9030069 - 26 Jul 2026

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Abstract

Implant-associated infections remain one of the leading causes of failure in orthopaedic and dental implants, necessitating the development of multifunctional surface coatings capable of simultaneously enhancing corrosion resistance, bioactivity, and antibacterial performance. The aim of this study was to investigate how picosecond laser [...] Read more.

Implant-associated infections remain one of the leading causes of failure in orthopaedic and dental implants, necessitating the development of multifunctional surface coatings capable of simultaneously enhancing corrosion resistance, bioactivity, and antibacterial performance. The aim of this study was to investigate how picosecond laser surface treatment modifies the structural, physicochemical, mechanical, electrochemical, bioactive, and antibacterial properties of magnetron-sputtered TiO₂/CuO coatings on Ti6Al4V alloy. Structural characterisation revealed that laser treatment transformed the predominantly amorphous TiO₂ matrix into a more crystalline rutile-containing structure while preserving the CuO phase. The laser surface-treated (LST) surface exhibited increased surface hydroxylation, enhanced wettability, and a slightly higher release of Cu ions. In addition to modifying the surface chemistry, laser treatment improved the mechanical characteristics of the coating, contributing to its overall durability and suitability for biomedical implant environments. Electrochemical impedance spectroscopy demonstrated that both coatings significantly improved the corrosion resistance of Ti6Al4V in simulated body fluid, whereas the laser-treated coating showed superior long-term stability and passive layer evolution. Following immersion, both surfaces promoted the formation of Ca–P-rich hydroxyapatite deposits, indicating favourable bioactivity. Antibacterial testing against Staphylococcus aureus revealed reductions in bacterial viability of 67% and 74% for the AD and LST coatings, respectively. The enhanced antibacterial performance of the laser-treated surface was attributed to the combined effects of increased crystallinity, surface hydroxylation, hydrophilicity, and copper ion release. The novelty of this work lies in demonstrating that picosecond laser post-treatment can simultaneously tailor the crystallinity, surface chemistry, morphology, corrosion resistance, bioactivity, and antibacterial performance of magnetron-sputtered TiO₂/CuO coatings without compromising coating integrity, thereby providing a promising multifunctional surface modification strategy for biomedical implants. Full article

(This article belongs to the Special Issue Surface Engineering for Biomedical Applications)

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16 pages, 4537 KB

Open AccessArticle

Effect of Bias Voltage on Multi-Element Nitride CAE-PVD Coatings on Ti6Al4V

by Cheng-Hsun Hsu, Ting-An Shih, Hong-Wei Chen and Wei-Che Huang

Surfaces 2026, 9(3), 68; https://doi.org/10.3390/surfaces9030068 - 23 Jul 2026

Viewed by 268

Abstract

Ti6Al4V alloy is widely used in biomedical and engineering applications; however, its limited wear resistance and lack of intrinsic antibacterial activity restrict its long-term performance. Although multi-element nitride coatings prepared by cathodic arc evaporation (CAE) have shown considerable potential, the influence of substrate [...] Read more.

Ti6Al4V alloy is widely used in biomedical and engineering applications; however, its limited wear resistance and lack of intrinsic antibacterial activity restrict its long-term performance. Although multi-element nitride coatings prepared by cathodic arc evaporation (CAE) have shown considerable potential, the influence of substrate bias voltage on their microstructural evolution and multifunctional performance remains insufficiently understood. In this study, (TiCrCuZrAlAg)N multi-element nitride coatings were deposited on Ti6Al4V substrates by CAE under substrate bias voltages of 50, 100, and 150 V. The effects of bias voltage on coating composition, crystal structure, hardness, wear behavior, and antibacterial performance were systematically investigated. Increasing the bias voltage enhanced ion bombardment, leading to reduced coating thickness, lower Cu/Ag incorporation, and degraded crystallinity, which consequently affected coating performance. Among the investigated conditions, the coating deposited at 50 V exhibited the highest hardness (1628.4 HV), the lowest wear rate (0.08 × 10⁻⁷ g/m), and the highest antibacterial efficiency (99.2%). This study establishes a correlation between substrate bias voltage, microstructural evolution, and multifunctional performance in CAE-deposited (TiCrCuZrAlAg)N coatings, providing practical guidance for the design of multifunctional protective coatings. Full article

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18 pages, 5751 KB

Open AccessArticle

Surface Engineering of PEEK Using Ultrashort Laser Pulses: A Pathway to Enhanced Cellular Response

by Liliya Angelova, Flora Lemaire, Halima Kerdjoudj, Aleksandra Zhelyazkova and Albena Daskalova

Surfaces 2026, 9(3), 67; https://doi.org/10.3390/surfaces9030067 - 22 Jul 2026

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Abstract

Polyetheretherketone (PEEK) has emerged as a promising biomaterial for orthopedic and craniofacial implants due to its favorable mechanical properties and fatigue resistance; however, its inherent chemical inertness limits effective osseointegration. In this study, femtosecond laser surface modification is explored as a strategy to [...] Read more.

Polyetheretherketone (PEEK) has emerged as a promising biomaterial for orthopedic and craniofacial implants due to its favorable mechanical properties and fatigue resistance; however, its inherent chemical inertness limits effective osseointegration. In this study, femtosecond laser surface modification is explored as a strategy to enhance the bioactivity of PEEK. Based on a previously performed parametric study, controlled micro- and nanoscale surface textures were fabricated using femtosecond laser processing, enabling precise tuning of surface roughness and wettability without the need for additional chemical treatment. The modified surfaces were systematically characterized in terms of morphology, composition, and topography using scanning electron microscopy (SEM), 3D profilometry, and water contact angle measurements. Four optimized femtosecond laser-generated surface architectures were selected for the present investigation and comprehensively characterized, followed by in vitro evaluation of dental pulp stem cell adhesion, morphology, and proliferation. The results indicate that laser-induced micro/nanostructuring enhances the surface properties of PEEK, while supporting cellular attachment and favorable cell–surface interaction. Differences in the biological response were observed among the optimized laser-textured surfaces. These findings highlight the feasibility of femtosecond laser texturing as a clean, reproducible, and scalable approach for the development of next-generation, personalized orthopedic implants. Full article

(This article belongs to the Special Issue Surface Engineering for Biomedical Applications)

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21 pages, 6634 KB

Open AccessArticle

Tribological and Corrosion Performance of Electroless Ni-P-Al₂O₃ Composite Coatings on Ti-6Al-4V Alloy

by Muhmmad Usman, Tauheed Shehbaz, Fahd Nawaz Khan, Muhammad Yasir and Julfikar Haider

Surfaces 2026, 9(3), 66; https://doi.org/10.3390/surfaces9030066 - 21 Jul 2026

Viewed by 296

Abstract

Electroless coatings mark a significant improvement in surface engineering by providing superior uniformity, precision, and functional properties compared with traditional plating processes. Electroless Ni-P-Al₂O₃ composite coatings were successfully deposited on Ti-6Al-4V, forming a Ni-Ti intermediate (~14–16 µm) that ensured strong [...] Read more.

Electroless coatings mark a significant improvement in surface engineering by providing superior uniformity, precision, and functional properties compared with traditional plating processes. Electroless Ni-P-Al₂O₃ composite coatings were successfully deposited on Ti-6Al-4V, forming a Ni-Ti intermediate (~14–16 µm) that ensured strong interfacial bonding. Al₂O₃ concentration (0.2–1.4 g/L) strongly influenced microstructure and performance, with 0.4 g/L yielding the most refined coating. AFM revealed a dense, uniform surface with the lowest roughness (~23.4 nm). This composition achieved the highest hardness (464.6 HV_0.1), ~157% higher than the substrate and ~53% higher than Ni-P. It also showed superior tribological behavior, reducing wear volume to ~4.46 × 10⁻⁷ mm³ and friction coefficient to ~0.32 (~85% and ~50% reductions vs. substrate). Corrosion resistance was maximized at 0.4 g/L, with the lowest corrosion current (2.45 × 10⁻⁶ A/cm²) and rate (0.0053 mpy), outperforming both Ni-P and uncoated Ti-6Al-4V due to the compact composite matrix and stable passive film. Full article

(This article belongs to the Topic Engineered Surfaces and Tribological Performance)

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27 pages, 1782 KB

Open AccessReview

Surface-Condition-Driven Fatigue Performance of Laser Powder Bed Fusion-Manufactured Alloys

by Samuel Onimpa Alfred

Surfaces 2026, 9(3), 65; https://doi.org/10.3390/surfaces9030065 - 19 Jul 2026

Viewed by 375

Abstract

Laser powder bed fusion produces geometrically complex metallic components, yet fatigue performance consistently falls below that of wrought counterparts. Surface condition, encompassing as-built roughness, residual stress, porosity, microstructure, and oxide layers, is the dominant factor driving this deficit. This review critically examines surface-driven [...] Read more.

Laser powder bed fusion produces geometrically complex metallic components, yet fatigue performance consistently falls below that of wrought counterparts. Surface condition, encompassing as-built roughness, residual stress, porosity, microstructure, and oxide layers, is the dominant factor driving this deficit. This review critically examines surface-driven fatigue mechanisms across Ti-6Al-4V, IN718, AlSi10Mg, and 316L alloys. Post-processing strategies, including mechanical polishing, peening, electrochemical polishing, laser polishing, burnishing, and hybrid approaches, are systematically evaluated. The mechanistic roles of surface roughness as a stress concentrator, near-surface porosity as a crack initiation site, and compressive residual stress as a crack-closure mechanism are discussed. Emerging burnishing techniques, particularly electrical current-assisted burnishing, have demonstrated fatigue life improvements of up to five-fold relative to as-built components. These findings underscore the potential of thermo-mechanical surface modification while emphasizing the need for broader validation across a wider range of alloys and loading conditions. Finally, this review identifies critical research gaps, notably the lack of standardized surface characterization protocols and the limited understanding of fatigue under multiaxial and variable-amplitude loading for surface-treated L-PBF parts, and outlines directions for future work. Full article

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21 pages, 13689 KB

Open AccessArticle

Femtosecond Laser Texturing of Ti-6Al-4V: From Ablation Behavior to Controlled Bi-Sinusoidal Surface Morphology

by Hassan Alzarif, Frédéric Robache, Romain Vayron, Maxence Bigerelle and Alex Montagne

Surfaces 2026, 9(3), 64; https://doi.org/10.3390/surfaces9030064 - 16 Jul 2026

Viewed by 301

Abstract

This work presents a systematic methodology for generating bi-sinusoidal surface topographies with controlled and reproducible characteristics on Ti-6Al-4V using a progressive 1D–2D–3D framework. Such deterministic topographies are of interest for dental implants, where surface micro-texture can influence an early biological response and osseointegration. [...] Read more.

This work presents a systematic methodology for generating bi-sinusoidal surface topographies with controlled and reproducible characteristics on Ti-6Al-4V using a progressive 1D–2D–3D framework. Such deterministic topographies are of interest for dental implants, where surface micro-texture can influence an early biological response and osseointegration. Single-pulse ablation thresholds were first determined to be 0.175 J/cm² at a 1031 nm wavelength using 306 fs pulses, with no polarization dependence. Studies were then carried out to identify fundamental ablation parameters, optimize scanning conditions for planar texturing, and extend the process to controlled three-dimensional surface architectures. During the 1D stage, increasing the fluence from 0.26 to 6.52 J/cm² enlarged the crater diameter from approximately 7 to 32 µm and increased the areal roughness Sa from 0.012 to 0.020 µm. With an increasing pulse number, the crater diameter continued to grow up to 25 pulses before stabilizing. Multi-pulse tests below the threshold showed that repeated exposures caused ablation, highlighting incubation and energy accumulation, with an incubation factor of S = 0.84. In the 2D stage, scanned irradiation was used to quantify how fluence and pulse overlap affect the ablated depth and areal roughness, with depth increasing linearly with the number of passes, and roughness strongly governed by overlap and fluence. Finally, 3D texturing combining x–y scanning with a z-axis focal adjustment enabled reproducible bi-sinusoidal topographies. Full article

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17 pages, 2785 KB

Open AccessArticle

by Ji-Young Kim, Hyun-Yeong Jung, Wan Yook and Seung-Chae Yoon

Surfaces 2026, 9(3), 63; https://doi.org/10.3390/surfaces9030063 - 14 Jul 2026

Viewed by 307

Abstract

A lubricant protective film (LP) formed on automotive Zn-coated steel sheets is a functional surface layer that controls shear resistance at the die–sheet interface while also affecting the electrical contact state during resistance spot welding and the surface reactivity during paint pretreatment. In [...] Read more.

A lubricant protective film (LP) formed on automotive Zn-coated steel sheets is a functional surface layer that controls shear resistance at the die–sheet interface while also affecting the electrical contact state during resistance spot welding and the surface reactivity during paint pretreatment. In this study, the effect of LP coating weight on surface friction, interfacial electrical resistance, and degreasing–phosphate reactivity was analyzed for 340 MPa-grade galvannealed (GA) steel sheets within a unified surface-governed framework. The LP coating weight was controlled in the range of 0–1008 mg/m² on a single-sided basis. The friction coefficient, cup-drawing limit blank holding force (BHF), resistance spot welding current range, resistance–time product obtained by integrating dynamic resistance with respect to time, residual LP after degreasing, phosphate coating formation behavior, and forming simulation results using experimentally measured friction coefficients as input were comparatively evaluated. With increasing LP coating weight, the friction coefficient decreased from approximately 0.163 to 0.130 and then increased again to approximately 0.145 in the high-coating-weight regime. This surface-state change increased the limit BHF during cup drawing, whereas it narrowed the current range and increased the resistance–time product during resistance spot welding. In addition, under conditions above approximately 550 mg/m², residual LP after degreasing increased, and local no-growth regions of the phosphate coating were identified. These results show that, within the present test conditions, LP coating weight is not merely the amount of lubricant applied but a surface-state variable that concurrently influences frictional, electrical, and chemical responses. Therefore, within the scope of the present laboratory-scale framework, an LP coating weight of approximately 300–550 mg/m² should be interpreted not as a universal optimum, but as an operational surface window derived by balancing formability, the RSW process window, and phosphate reactivity under the present experimental conditions. Full article

(This article belongs to the Topic Engineered Surfaces and Tribological Performance)

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18 pages, 3736 KB

Open AccessArticle

Constructing a Polyimide/Zinc Sulfide Heterojunction Photocatalyst for Enhanced Photocatalytic Performance

by Binru Zhang, Baotong Liu and Chenghai Ma

Surfaces 2026, 9(3), 62; https://doi.org/10.3390/surfaces9030062 - 10 Jul 2026

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Abstract

Photocatalytic decomposition of water to produce hydrogen and the degradation of organic pollutants are among the most ideal strategies for addressing energy shortages and environmental pollution. Moreover, constructing organic–inorganic heterojunctions based on surface interactions is one of the most effective strategies for enhancing [...] Read more.

Photocatalytic decomposition of water to produce hydrogen and the degradation of organic pollutants are among the most ideal strategies for addressing energy shortages and environmental pollution. Moreover, constructing organic–inorganic heterojunctions based on surface interactions is one of the most effective strategies for enhancing photocatalytic activity. In this work, a novel II-type polyimide/zinc sulfide (PI/ZnS) heterojunction photocatalyst was successfully synthesized for the first time through a simple hydrothermal method. The influence of PI in the PI/ZnS composite material was systematically studied. The 1PI/ZnS composite shows the highest rate (587.7 μmol/g/h) of photocatalytic water splitting for hydrogen production, which is approximately 19% higher than the value of ZnS (492.5 μmol/g/h), and it is 34.6 times the PI value (16.95 μmol/g/h). The degradation efficiency of the 3 PI/ZnS composite is nearly 35.5 times that of PI and nearly 1.9 times that of ZnS. The enhancement in the photocatalytic activity of the PI/ZnS photocatalyst is mainly attributed to the dense interface and II-type heterojunction between the PI and ZnS, which effectively improves the spatial separation efficiency of photogenerated carriers. This study demonstrates that the nanostructured II-type heterojunction in the PI/ZnS composite can significantly improve the photocatalytic performance of polyimide photocatalysts. Full article

(This article belongs to the Special Issue Cutting-Edge Developments in Photocatalysis and Photovoltaics)

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17 pages, 4357 KB

Open AccessArticle

Enhancing Mechanical Properties and Corrosion Resistance of GW63K Magnesium Alloy via Ultrasonic Surface Rolling Process

by Tian Lan, Xiaowei Wang, Binbin Liu, Feng Ye, Lun Cui and Haoyang Du

Surfaces 2026, 9(3), 61; https://doi.org/10.3390/surfaces9030061 - 10 Jul 2026

Viewed by 267

Abstract

In this study, an ultrasonic surface rolling process (USRP) was employed to enhance the surface performance of a GW63K-T6 magnesium alloy. The results show that the USRP induces a gradient-distributed {10–12} deformation twin structure in the surface layer, with twin density decreasing progressively [...] Read more.

In this study, an ultrasonic surface rolling process (USRP) was employed to enhance the surface performance of a GW63K-T6 magnesium alloy. The results show that the USRP induces a gradient-distributed {10–12} deformation twin structure in the surface layer, with twin density decreasing progressively from the surface inward. Following USRP treatment, surface microhardness increased by approximately 40%, yield strength (YS) by about 26%, and ultimate tensile strength (UTS) by roughly 11%. Corrosion resistance was also significantly improved, as evidenced primarily by a weight loss reduction of approximately 50% after 120 h of immersion corrosion and further supported by polarization curves with a positive shift in corrosion potential and a decrease in current density for the USRP-treated samples. The observed improvements in mechanical properties and corrosion resistance are closely associated with the gradient twin structure. These findings suggest that the USRP is a promising technique for the simultaneous enhancement in mechanical and corrosion properties of Mg-RE alloys, although further investigation is needed to fully elucidate the underlying mechanisms. Full article

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23 pages, 29578 KB

Open AccessReview

A Review on Recent Progress in Superhydrophobic Materials for Building Waterproofing

by Yanxi Qiao, Shahid Muhammad, Chaoke Liu, Yue Ru, Wenlu Liu, Dali Gao and Cunming Yu

Surfaces 2026, 9(3), 60; https://doi.org/10.3390/surfaces9030060 - 9 Jul 2026

Viewed by 341

Abstract

Waterproofing is crucial for maintaining the structural integrity and extending the longevity of buildings. However, traditional waterproofing materials possess limitations, including restricted durability, complex installation procedures, and environmental pollution, making them insufficient to meet the advanced waterproofing demands of modern buildings under complex [...] Read more.

Waterproofing is crucial for maintaining the structural integrity and extending the longevity of buildings. However, traditional waterproofing materials possess limitations, including restricted durability, complex installation procedures, and environmental pollution, making them insufficient to meet the advanced waterproofing demands of modern buildings under complex conditions. Superhydrophobic materials, characterized by a water contact angle greater than 150° and a water sliding angle less than 10°, exhibit low surface energy, self-cleaning properties, and corrosion resistance due to their distinctive micro–nano structure and chemical composition, thereby serving as an innovative high-performance solution for building waterproofing and helping address some limitations of traditional waterproofing technologies. This review systematically elucidates the fundamental wetting theory and formation mechanisms of superhydrophobic materials, categorizes superhydrophobic materials used in building waterproofing mainly according to substrate type, discusses their modification strategies and key functional components, and conducts a detailed analysis of their application scenarios, performance advantages, and engineering test data in the waterproofing of concrete structures, steel structures, and building envelope materials (wood, stone, building coatings). Furthermore, this review analyzes the technical bottlenecks, performance limitations, and industrialization challenges associated with the current practical application of superhydrophobic building waterproofing materials, and outlines future development trends and engineering application strategies from the perspectives of material performance optimization, cost control, construction technology enhancement, and standardization. Full article

(This article belongs to the Special Issue Superhydrophobic Surfaces: Wetting Phenomena and Preparation Methods)

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22 pages, 1912 KB

Open AccessArticle

Interfacial Activation and Electronic Coupling at Platinum Electrodes Induced by Vitamin B6 and Silver Nanoparticles in Sulfate Electrolyte: A CV-EIS-UV-Vis Study

by Bogdan Tutunaru

Surfaces 2026, 9(3), 59; https://doi.org/10.3390/surfaces9030059 - 2 Jul 2026

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Abstract

This study establishes a unified electrochemical–optical framework to elucidate adsorption-controlled charge transfer and electronic excitation at platinum–electrolyte interfaces modified by biomolecules and metal nanoparticles. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and UV-Vis absorption spectroscopy with Tauc analysis were used to probe transformations [...] Read more.

This study establishes a unified electrochemical–optical framework to elucidate adsorption-controlled charge transfer and electronic excitation at platinum–electrolyte interfaces modified by biomolecules and metal nanoparticles. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and UV-Vis absorption spectroscopy with Tauc analysis were used to probe transformations induced by vitamin B6 (pyridoxine) and silver nanoparticles (nAg) in Na₂SO₄ aqueous electrolytes. In the supporting electrolyte, platinum behaves as a blocking capacitive interface with nearly symmetric anodic–cathodic charges, high charge-transfer resistance (R_ct ≈ 3.14 kΩ·cm²), low double-layer capacitance (C_dl ≈ 4.0 × 10⁻⁵ F·cm⁻²), and deep-UV transitions (E_low ≥ 3.8 eV), confirming the electrochemical inertness of sulfate media. Vitamin B6 molecules interact with the electrode surface and modify the structure of the electrical double layer at the platinum/electrolyte interface, restructuring the double layer, increasing C_dl (≈1.2 × 10⁻⁴ F·cm⁻²), decreasing R_ct (≈0.23 kΩ·cm²), and generating irreversible surface-confined anodic processes. Tauc plots yield two transitions (E_low ≈ 2.9 eV; E_high ≈ 4.1 eV), attributed to molecular states and weak charge-transfer interactions. The results suggest electronic interactions between the silver nanoparticles and the adsorbed vitamin B6 molecules at the electrode interface. Strong electronic interactions between vitamin B6 and nAg yields ultralow R_ct (≈58 Ω·cm²), enhanced pseudocapacitance (C_dl ≈ 2.9 × 10⁻⁴ F·cm⁻²), and red-shifted transitions (E_low ≈ 2.2 eV; E_high ≈ 3.7 eV). These results show that adsorption-induced electronic coupling governs interfacial kinetics and optical excitation pathways. Full article

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Surfaces, Volume 9, Issue 3 (September 2026) – 14 articles

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