Search

Funding Information: This work was supported by Business Finland through project Molecular Modelling in Industrial Research and Development (MM-IRD). The authors wish to acknowledge CSC – IT Center for Science, Finland, for computational resources. Publisher Copyright: © 2023 The Author(s) Oxygen and water are the most reactive gases of the ambient air. The adsorption of both molecules on transition metal surfaces have been studied extensively, but mostly separately. However, water and oxygen usually co-exist, and therefore realistic systems need to take into consideration both simultaneously. As these adsorption reactions are so common, state-of-the-art results are beneficial as they capture large trends as accurately as possible. A comprehensive study of oxygen and water co-adsorption and dissociation on Ag(111)-, Au(111)-, Pd(111)-, Pt(111)-, Rh(111)- and Ni(111)-surfaces have been performed using density functional theory. We present a very strong general trend, where dissociated oxygen systematically lowers the activation energy of water dissociation on transition metal surfaces. This makes the oxygen dissociation the rate-determining step of the water dissociation reaction. The effect is caused by the additional pathway that the dissociated oxygen enables for the dissociation of water molecule.

Machining of titanium alloys such as Ti-6Al-4 V can be very intimidating due to their low thermal conductivity leading to elevated cutting temperatures at the chip-tool interface (ICT). In this regard, the self-lubrication effect of coatings like TiSiVN represented by topography, oxidation, and diffusion at the chip-tool interface are crucial. Thus, the present work investigates the latter three mechanisms during dry machining of Ti-6Al-4 V titanium alloy with uncoated and TiSiVN coated Al2O3/SiC whiskers-reinforced ceramic cutting tools. The results reveal that the adhesion height (AH) and O% increases with cutting temperature, showing the dominant influence of cutting temperature on material adhesion and oxidation levels at the ICT. AH increases with increased cutting speed for both coated tools, indicating that the crater depth increment was not so severe for the coated tools. However, a drastic upward surge of crater depth for uncoated and TiSiN coated tools at 125 m/min cutting speed makes the crater edge near the ICT act as a chip breaker and facilitates the chip's bending away from the tool face causing reduction in chip bend angles (BA). Additionally, the TiSiVN coating accounts to a reduction of approximately 23% in AH and 18% in Ti%, and 37% lower oxygen levels at the highest cutting speed when compared to the uncoated tool primarily due to lower cutting temperatures and self-lubricating behavior. The work is supported by Maria Zambrano grants and funded by: MCIN/AEI/10.13039/501100011033 and “FSE invierte en tu futuro”, and Basque Government university group IT1573-22, High performance machining, and MiCINN PDC2021–121792-I00 “New tooling production oriented to manufacture high value-added components of turbomachinery” (Haute Couture Taylor Made). The authors are also grateful to Grant PID2019-109340RB-I00 funded by MCIN/AEI/10.13039/5 The authors thank SGIker (UPV/EHU/ERDF, EU) for technical and human support provided. Also, Filipe Fernandes acknowledges the MCTool21 - ref. "POCI-01–0247- FEDER-045940" and CEMMPRE – ref. “UIDB/00285/2020″ projects, sponsored by FEDER funds through the COMPETE program – Operational Program on Competitiveness Factors – and by national funds through FCT – Foundation for Science and Technology.

Colloidal properties of viruses largely define the stability, transport, and host interactions of viruses. Despite attempts to unravel the correlation between colloidal virus properties and their interactions outside and inside their host, an in-depth understanding is still missing. This knowledge gap is, to a great extent, caused by challenges associated with the capacity to probe these properties experimentally; thus, great efforts are being invested in developing new approaches or transforming existing ones to characterize the physical-chemical, i.e., colloidal, properties of viruses. Understanding the correlation between these properties and virus interactions is not only important from a scientific point of view but will also hopefully inspire the design of novel viral vectors and virus-like particles for biomedical applications. In this review, we cover the recent experimental advances in characterizing the colloidal properties of viruses with particular attention to virus hydrophobicity, genetic load, nanomechanical properties, and surface interaction forces with host cells., Current Opinion in Colloid & Interface Science, 66, ISSN:1879-0399, ISSN:1359-0294

Two structurally distinct phases of manganese oxide ultrathin films were grown on Au(111) substrates and imaged at atomic resolution by scanning tunneling microscopy (STM). The so-called MnOx fishbone phase is only a few monolayers thick and nucleates epitaxially on the bare Au(111) substrate. The surface of this phase exhibits two parallelogram unit cells with sizes and included angles of (14.6 ± 0.2) × (5.6 ± 0.2) Å2, 88 ± 1° and (13.6 ± 0.1) × (5.6 ± 0.2) Å2, 80 ± 1°. The other thicker phase is called the square phase. It is only observed growing on top of the fishbone phase and has a surface unit cell of edge dimension 5.8 ± 0.1 Å. The square phase is thought to be a (001) termination of hausmannite Mn3O4. In addition, less common intermediary surface structures are also observed. This study demonstrates the transition of the crystal structure of an oxide film from a unique ultrathin film structure that is epitaxially constrained by the interaction with the Au(111) substrate to that of a thicker film with the structure of a bulk crystal.

This work is the result of a problem of premature development of rail corrugation found on a new metro line. As urgent solutions, a rail grinding was carried out and friction modifier started to be applied. Experimental corrugation measurements have been taken periodically in this line at 60 control points since 2018, and an extensive database has been collected since then. As a second stage, a computationally efficient new model has been developed to predict corrugation growth under different running conditions. The aim of this work has been to obtain feasible solutions to delay corrugation growth in metro type lines. The authors gratefully acknowledge financial support from the European Horizon 2020 Joint Technology Initiative Shift2Rail (IN2TRACK3) [101012456], from the Spanish Research Ministry MICINN/Economy and Competitiveness Ministry MINECO and MCI/AEI [PID2019-109483RB-I00], including funding by the FEDER-ERDF European Regional Development Fund, and from the Basque Government [IT1764-22, PRE_2021_2_0047, KK-2023/00029].

Iron-based coatings are an attractive solution for many wear applications, considering sustainability requirements such as avoidance of critical raw materials and toxic substances. Cold worked tool steels are one potential, yet very undiscovered, material option for coating applications. As a bulk, their careful heat treatment typically produces a martensitic carbide microstructure with very good wear resistance. Compared to bulk materials, the thermal history of a thermally sprayed coating in the as sprayed state is quite different as the microstructure of the sprayed coating does not form in equilibrium. This study explored the potential of AISI D2 cold worked tool steel as a thermal spray coating under different wear conditions. The study investigated different heat treatments to achieve different microstructures of the powder and coatings and their effect on the wear and cavitation erosion properties of the HVOF and HVAF sprayed thermally sprayed tool steel coating. It is important to understand whether the properties of thermally sprayed coatings, which initially have a high defect density, can be improved by heat treatments, and how modification of the phase structures of iron-based coatings affects their properties, in order to extend the use of these coatings.

The understanding and experimentation of abrasive wear mechanisms at high speeds is still poorly investigated in literature. This is mainly due to a lack of suitable, well-instrumented test rigs for fundamental, single abrasive wear events. Standard scratch tests, which are often utilized for studies of abrasion phenomena, operate in the low-speed range up to some mm/s, while applications suffering from abrasive wear often operate at speeds exceeding 1 m/s (e.g., rolling, grinding, machining). Numerical approaches, especially particle-based methods, allow the simulation of such fast deformation processes, but rely on hardening models that require a precise knowledge of material parameters. Thus, the Johnson-Cook material model was parametrized using data from high-speed compression tests of pure aluminum. A series of scratch tests with increasing depths were then simulated using the particle-based Material Point Method (MPM). Experimentation was done on a pendulum scratch test rig equipped with a Rockwell C diamond cone. By adjusting the balance point of the swing arm of ~1 m length, a velocity of 6.8 m/s was achieved at its tip as measured with a high-speed camera. Scratches of several depths were performed, and their force signals acquired. Post-test analyses comprised topography measurements and EBSD on cross-sections of the scratches to investigate the microstructural changes due to the high-speed wear event. Scratch topographies and abrasive mechanisms compared favorably between experiment and simulation for the aluminum. The extent of strain hardening was significantly reduced compared to low-speed experiments. The calibration of the high-speed force sensor was successful and now allows the investigation of new alloys and determination of material parameters under high-speed abrasive conditions.

SnSe is semiconductor with various applications in optoelectronic devices, but its synthesis still facing challenges. Here, an original approach to tune the morphology, the optical properties and microstructure of SnSe films is proposed, based on the change of pulse duration during electrodeposition. The syntheses were carried out at a unique applied potential of −0.55 V vs AgCl/Ag with pulse durations (tON) ranging from 50 ms to 500 ms. The microstructure was systematically studied with SEM, TEM, XRD and XPS characterizations. First, the formation of SnSe of compact films without pinholes is demonstrated, with no significant change of composition (Se/Sn ratio close to 1:1). All the films are crystalized according to the Pnma orthorhombic phase with a preferential growth direction perpendicular to the (1 1 1) direction. The increase of pulse duration from 50 to 500 ms reduces the crystallinity of film, but less Se and SnO2 by-products are formed. Finally, the absorption coefficient of the films was extracted from ellipsometric measurements and evaluated in the near-edge region to evaluate the optical bandgaps. The results confirmed a slight change in the optical bandgap, from 1 to 1.1 eV. This work opens new alternative to tune physico-chemical properties of SnSe films.

The demand for sustainable products is increasing worldwide and cosmetic industry is not an exception. Besides exploring nature as source of new ingredients, their production must be sustainable and should use environmentally friendly processes. In this work, biogenic silica microparticles were synthesized from sugarcane ash, and their potential application as cosmetic and skincare ingredient was evaluated. For such application, several properties were validated, including cytotoxicity in skin keratinocytes, potential sensitization effect on skin peptides, stimulation of pro-collagen I alpha 1, wound healing capacity, as well as the ingredient stability along a storage period. Biogenic silica showed to be non-cytotoxic on skin keratinocytes, at concentrations up to 5 wt%, and non-skin sensitizer. A positive effect on the stimulation of pro-collagen I alpha 1 suggests a potential anti-ageing activity, while the migration of fibroblasts to a wounded area suggests a regenerative capacity. Under an accelerated stability study, biogenic silica showed an increase on the loss on drying, but no changes were observed on its functional properties, mainly oil absorption capacity, as well the microbiological quality, which was maintained. Overall, novel biogenic silica microparticles produced from a sustainable source are safe, stable over time and have potential to be used as a cosmetic and skincare ingredient.

One of the key challenges in the field of flexible electronics relies on finding conductive materials that can withstand bending and stretching stresses while maintaining their performance. In this context, this work presents a comparative study of laser-induced conductive materials from the direct laser-scribing of two commercial flexible films: the benchmark Kapton® HN polyimide (PI) precursor and the UltemTM 1000 polyetherimide (PEI) alternative contender. The synthesis process on both materials is optimized in terms of electrical conductivity using a high-performance galvanometric laser with a wavelength of 532 nm for the fabrication of multiple samples at different laser powers and speeds. The samples are structurally characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Fourier-Transform Infrared Spectroscopy (FTIR) aiming at understanding the chemical and physical changes of the ablated material. The results demonstrate that the proposed setup is feasible for the synthesis of uniform and reliable conductive patterns on the surface of both substrates with high reproducibility. In particular, it is proved that PEI is more suitable precursor for flexible electronics applications which demand high electrical conductivity, leading to a sheet resistance of 3.62 ± 0.35 Ω/sq at 0.8 W and 5 mm/s once the laser-synthesis process is optimized (against the 6.04 ± 0.63 Ω/sq at 0.6 W and 5 mm/s offered by the LIG on PI). The performance of both laser-induced patterns as electrodes for the fabrication of electrochemical capacitors is also studied and compared in terms of areal specific capacitance., FEDER/Junta de Andalucía-Consejería de Transformaci´on Econ´omica, Industria, Conocimiento y Universidades Project P20_00265 and Project BRNM-680-UGR20; Project TED2021-129949A-I00, MCIN/AEI/10.13039/ 501100011033, European Union NextGenerationEU/PRTR, Grant PID2020-117344RB-I00, MCIN/AEI 10.13039/ 501100011033, Junta de Andalucía – Consejería de Universidad, Investigaci´on e Innovaci´on through the project ProyExcel_00268, Spanish Ministry of Sciences and Innovation through the Ram´on y Cajal fellow RYC2019- 027457-I, María Zambrano fellow C21.I4.P1, grant PRE2021-096886.

The present work aimed at studying the in vitro digestion fate of κ-carrageenan (KC) or agar (AG) emulsion gels (EG), and KC oil-filled aerogels (OAG) in terms of their structural changes, lipolysis kinetics and curcumin bioaccessibility. On the one hand, both EG and aerogels showed large (70-200 µm) and heterogeneous particles after gastric conditions, indicating the release of bulk oil and gelled material. Nonetheless, this material release in the stomach phase was lower in the case of EG-AG and OAG-KC compared to EG-KC. After small intestinal conditions, EG and oil-filled aerogels presented a wide range of particle sizes probably due to the presence of undigested lipid material, gelled structures, as well as lipid digestion products. For the most part, adding curcumin to the structures' lipid phase did not cause of the structural modifications that occurred at the different in vitro digestion phases. On the other hand, the lipolysis kinetics was different depending on the type of structure. Amongst emulsion-gels, those formulated with κ-carrageenan presented a slower and lower lipolysis kinetics compared to those formulated with agar, which could be attributed to their higher initial hardness. Overall, the addition of curcumin in the lipid phase decreased the lipolysis in all the structures, which evidenced its interference in the lipid digestion process. The curcumin bioaccessibility reached high values (≈ 100 %) for all the studied structures, presenting a high solubility in intestinal fluids. This work unravels the implications of microstructural changes of emulsion-gels and oil-filled aerogels during digestion and their impact on their digestibility and subsequent functionality., This study was funded by the Ministry of Science, Innovation and Universities throughout the projects RTI2018–094268-B-C21 (University of Lleida) and RTI2018–094268-B-C22 (Agencia Estatal Consejo Superior de Investigaciones Cientificas (CSIC)).

We demonstrate a polymer brush assisted approach for the fabrication of continuous zirconium oxide (ZrO2) films over large areas with high uniformity (pin-hole free) on copper (Cu) substrates. This approach involves the use of a thiol-terminated polymethyl methacrylate brush (PMMA-SH) as the template layer for the selective infiltration of zirconium oxynitrate (ZrN2O7). The preparation of a highly uniform covalently grafted polymer monolayer on the Cu substrate is the critical factor in fabricating a metal oxide film of uniform thickness across the surface. Infiltration is reliant on the chemical interactions between the polymer functional group and the metal precursor. A following reductive H2 plasma treatment process results in ZrO2 film formation whilst the surface Cu2O passive oxide layer was reduced to a Cu/Cu2O interface. Fundamental analysis of the infiltration process and the resulting ZrO2 film was determined by XPS, and GA-FTIR. Results derived from these techniques confirm the inclusion of the ZrN2O7 into the polymer films. Cross-sectional transmission electron microscopy and energy dispersive X-ray mapping analysis corroborate the formation of ZrO2 layer at Cu substrate. We believe that this quick and facile methodology to prepare ZrO2 films is potentially scalable to other high-κ dielectric materials of high interest in microelectronic applications.

The abrasive and adhesive wear behaviour of metallic bonds can be significantly affected by varying pH values of the attacking medium. However, the knowledge about the pH value influence on diamond impregnated bits used in core drilling industry is still limited. One recent publication shows the advantage of modifying a standard ASTM B611-13 test to investigate the abrasive and adhesive wear behaviour of a diamond segment bond material in a neutral regime (pH7). This study mainly focuses on the effects of a varying surrounding media on the tribological behaviour using an acidic, neutral and alkaline slurry. This emulates more aggressive conditions for the diamond segments used in mining as well as construction industry. The pH value at which such diamond segments operate can differ from pH2 up to a value of pH13. The present work studies the wear behaviour of two metallic bonds in a modified B611-13 arrangement at 4 m/s sliding speed and different pH values. The tested specimens are investigated with regard to their change in mass and microstructure at the sliding interface zone. The results reveal a significant influence of the pH value on the wear behaviour of the bond system., Wear, 518-519

Typical Cu(In,Ga)Se2 solar cells are deposited on an opaque molybdenum back contact. However, for applications such as bifacial, semi-transparent or tandem solar cells a transparent back contact is required, for which various transparent conductive oxides have been tested, such as indium- or fluorine-doped tin oxide, and hydrogen-doped indium oxide. Here, a radio-frequency magnetron sputtering deposition process for In2O3:H (IOH) is investigated, where H is supplied from a Ar/H2 (5%) mixed gas and oxygen is pulsed during the entire deposition at room temperature. After deposition, the films are post-annealed in vacuum to optimize their optoelectronic properties. The oxygen plays an important role for the optoelectronic properties, where a high content of oxygen allows higher transparency but also increases the film sheet resistance. Optimum oxygen and Ar/H2 partial pressures of 3.2 E-2 Pa and 13E-2 Pa, respectively, were found, producing IOH films with average visible transparency of 87% and sheet resistance after annealing of 19 Ohm/sq., This work was supported by the project “Semi-Transparent Solar cells for building integrated photovoltaics (STAR-SOL)”, funded by FCT – Fundação para a Ciência e a Tecnologia (FCT‐FNR/0001/2018). Marina Alves thanks the Fundação para a Ciência e a Tecnologia (FCT), Portugal for the PhD Grant (2020.06063.BD).

In this study, we demonstrate that metallic substrates with a nanocrystalline grain size can be structured down to the micro- and nanometre range during a room temperature nanoimprinting process. WC-Co hard metal dies are patterned by Direct Laser Interference Patterning (DLIP), generating an array of separated asperities with a height of 4.7 µm and a spacing of 11.3 µm. Additionally, Laser Induced Periodic Surface Structures (LIPSS) with a spacing of 500 nm are formed as a hierarchical substructure. The patterned dies can be used to deform metallic substrates due to their high hardness. For structure replication, the WC-Co tool is pressed onto a nanocrystalline CuZn30 model alloy at room temperature. The pattern transfer process from the hard metallic tool to the nanocrystalline alloy is discussed in detail: At low contact pressures, the asperities on the tools act as single contact points, leading to the formation of separated dimples with a depth of up to 0.8 µm in the nanocrystalline alloy. At high contact pressures, the tool pattern, including the LIPSS is almost completely transferred to the substrate. The formed asperities protrude out of the surface, with a height to width aspect ratio of 0.4. It is thereby demonstrated, that plastic flow processes during the imprinting of nanocrystalline alloys allow for the replication of the DLIP tool pattern, even down to nano-scaled LIPSS. The imprinted array of surface asperities exhibits hydrophobic properties, due to a combined topographical and chemical influence on the wetting behaviour.

5 pags., 5 figs., 1 tab., We report the successful preparation and characterization of active silicon oxynitride thin films with controlled europium (Eu) doping by alternated pulsed laser deposition. The successful Eu doping with a nanostructured dopant distribution, as well as the stoichiometry of the oxynitride film, have been determined by ion beam analysis (RBS). The oxidation state of the incorporated Eu ions has been determined by in-depth x-ray photoelectron spectroscopy (XPS) and it is shown that the Eu ions are in the 2+ state, in contrast to the usual results found in oxide matrices for which the 3+ oxidation state prevails. The Eu-doped films show an intense broadband emission (FWHM >210 nm) associated to the optical transition fd → S of the Eu ions within the amorphous matrix. As expected, the intensity of the emission band increases as the Eu concentration increases, and it is remarkable that the emission shifts towards longer wavelengths. In terms of the chromatic coordinates (CIE) this implies a color tuning from a bluish to orange that enables color tunable emission, and potential white like emission by combining layers with different Eu ions concentration. Therefore, the developed oxynitride films with controlled Eu ions concentration achieved by PLD are promising for the development of color -tailored LED's., This work was partially funded by Spanish grants MINECO/FEDER TEC2015-69916-C2-1-R, MICINN/FEDER RTI2018-096498-B-I00 and PID2021-123190OB-I00, and by the CSIC (Spain) grants PIE202050E195 and AEPP2021-128. I.C. acknowledges the financial support through CSIC scholarship JAE-Pre2011 00578. A.M. acknowledges the financial support through FPI grant BES-2013-062593

The main aim of this research was to investigate the influence of graphite as an additive to a plasma-sprayed alumina coating matrix for tribological trends. For the deposition process, pure alumina and alumina with graphite (5%, 10% and 15%) weight percentage powders were used. The graphite-modified alumina coatings were formed on steel substrates by atmospheric plasma spraying using an air-hydrogen plasma. The influence of graphite content on the elemental composition, phase structure, friction coefficient, and specific wear rate was investigated. It was obtained that the addition of graphite enhanced the γ-Al2O3 phase content in the as-sprayed coatings. The highest γ-Al2O3 phase fraction was obtained when the amount of graphite in the feedstock powders was 10 wt.%. The elemental composition results indicated that the concentration of carbon in the alumina-graphite coatings was up to six times lower in comparison to the initial feedstock, and had varied from ∼1.7 to 2.45 wt.%. The incorporation of graphite slightly reduced the friction coefficient of the composite coatings due to the formation of a self-lubricating layer under dry-sliding conditions. The specific wear rates were in the range of ∼10−6 mm3/(Nm) for the alumina-graphite composite coatings, which were similar to the alumina coating, and were an order lower compared to the wear rate of steel.

It is now clear that growing flat graphene nanostructures from the gas phase on planar substrates is possible. One of the keys to success —particularly in producing a very large specific surface in a reduced space— is the use of 3D carbon nanostructures (i.e., vertical graphene nanowalls, VGNWs) over a planar substrate as a growth template for the deposition of electrochemically active materials (as, for example, transition metal oxides (TMO)). Vertical graphene nanowalls, also known as petal-like, vertical graphene flakes or vertical graphene, can achieve a very large specific surface area of 1100 m2/g, which is comparable to or greater than that of carbon nanotubes —the reference material for its use in high-performance supercapacitors or in other energy-related applications requiring a large active surface area. Vertical graphene nanowalls also exhibit high vertical and in-plane electrical conductivity when grown on metal electrodes, which benefits their use in electrochemical applications. Here, we focus on the growth of VGNWs on flexible stainless-steel substrates (SS310), in principle suitable for applications to electrodes of electrochemical systems (batteries, supercapacitors, catalysts), by inductively coupled plasma chemical vapour deposition (ICP-CVD), from methane as a carbon precursor, in a wide range of temperatures (575 to 900 °C). We will discuss the effect of growth temperature on morphological and structural characteristics of VGNWs based on the results of Raman spectroscopy and field emission scanning electron microscopy (FE-SEM) analysis. Because the nanostructures of graphene nanowalls reported to date are, for the most part, based on multi-layered graphene, here we seek to highlight the effect of temperature on the number of atomic layers of VGNW. In the 700–750 °C range, and under the plasma conditions explored, vertical graphene nanowalls are bilayer, which is foreseen to directly affect the magnitude of the VGNW specific surface., The authors acknowledge financial support from Grant ENE2017- 89210-C2-2-R, PID2020-116612RB-C31 and PID2020-116612RB-C32 funded by MCIN/AEI/ 10.13039/501100011033 and, as appropriate, by “ERDF A way of making Europe”, by the “European Union” or by the “European Union NextGenerationEU/PRTR”. The ENPHOCAMAT group acknowledges support from the AGAUR of Generalitat de Catalunya, Project No. 2017SGR1086. Two authors (A.M.-A and I.A.) acknowledge the financial supports from APIF grant from Universitat de Barcelona and from FPU grant from MEC of Spain. I.A. also acknowledges the support for a 6 months contract, as a research collaborator during the final period of his doctoral thesis, from the project entitled “Textile Competence Centre Vorarlberg 2” (TCCV2) of the program COMET-PROJECTS (Competence Centres for Excellent Technologies) of Austria. Other author (S.C.) acknowledges support from the postdoctoral fellowhips programme Beatriu de Pinós, funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 programme of research and innovation of the European Union under the Marie Sklodowska-Curie grant agreement No 801370 (H2020-MSCA-COFUND-2017)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Honing processes are usually employed to manufacture combustion engine cylinders and hydraulic cylinders. Honing provides a crosshatch pattern that favors the oil flow. In this paper, Adaptive Neural Fuzzy Inference System (ANFIS) models were obtained for tool wear, average roughness Ra, cylindricity and material removal rate in finishing honing processes. In addition, multi-objective optimization with the desirability function method was applied, in order to determine the process parameters that allow minimizing roughness, cylindricity error and tool wear, while maximizing material removal rate. The results showed that grain size and tangential velocity should be at their minimum levels, while density, pressure and linear velocity should be at their maximum levels. If only roughness, cylindricity error and tool wear are considered, then low grain size, low pressure and low linear velocity are recommended, while density and tangential velocity vary, depending on the optimization algorithm employed. This work will help to select appropriate process parameters in finishing honing processes, when roughness, cylindricity error and tool wear are to be minimized. The authors would like to thank the company Honingtec S.A. as well as Alejandro Domínguez for their help with the experimental tests. Financial support of these studies from Gdańsk University of Technology, Poland, by the DEC-6/2021/IDUB/IV.2/EUROPIUM application number 035506 grant under the IDUB - ‘Excellence Initiative - Research University’ program is gratefully acknowledged.

The development of anti-icing robust surfaces is a hot topic nowadays and particularly crucial in the aeronautics or wind energy sectors as ice accretion can compromise safety and power generation efficiency. However, the current performance of most anti-icing strategies has been proven insufficient for such demanding applications, particularly in large unprotected zones, which located downstream from thermally protected areas, may undergo secondary icing. Herein, a new testing methodology is proposed to evaluate accretion mechanisms and secondary icing phenomena through, respectively, direct impact and running-wet processes and systematically applied to anti-icing materials including commercial solutions and the latest trends in the state-of-the-art. Five categories of materials (hard, elastomeric, polymeric matrix, SLIPS and superhydrophobic) with up to fifteen formulations have been tested. This Round-Robin approach provides a deeper understanding of anti-icing mechanisms revealing the strengths and weaknesses of each material. The conclusion is that there is no single passive solution for anti-ice protection. Thus, to effectively protect a given real component, different tailored materials fitted for each particular zone of the system are required. For this selection, shape analysis of such a component and the impact characteristics of water droplets under real conditions are needed as schematically illustrated for aeronautic turbines. The project leading to this article has received funding from the EU H2020 program under grant agreement 899352 (FETOPEN-01-2018-2019-2020 - SOUNDofICE). The authors also thank the MINECO-AEI (MAT2016-79866-R, PID2019-109603RA-I00 and PID2019-110430GB-C21) funded by MCIN/AEI/10.13039/501100011033 and by “ERDF (FEDER) A way of making Europe”, to RTI2018-096262-B-C44–MAITAI, Multidisciplinary Approach for the Implementation of New Technologies to prevent Accretion of Ice on aircraft, funded by MCIN/AEI/10.13039/501100011033 (Ministerio de Ciencia, Innovación y Universidades—Retos) and CSIC 202160E002-217538, for financial support. CLS thanks the University of Seville through the VI “Plan Propio de Investigación y Transferencia de la US”(VI PPIT-US) and the Ramon y Cajal Grant program.

Surface silanols (SiOH) are important moieties on glass surfaces. Here we present a tag-and-count approach for determining surface silanol densities, which consists of tagging surface silanols with Zn via atomic layer deposition (ALD) followed by detection of the zinc by high sensitivity-low energy ion scattering (HS-LEIS). Shards of fused silica were hydroxylated with aqueous hydrofluoric acid (HF) and then heated to 200, 500, 700, or 900 °C. These heat treatments increasingly condense and remove surface silanols. The samples then underwent one ALD cycle with dimethylzinc (DMZ) or diethylzinc (DEZ) followed by water. As expected, fused silica surfaces heated to higher temperatures showed lower Zn coverages. When fused silica surfaces treated at 200 °C were exposed to DMZ for two different dose times, the same sub-monolayer quantity of Zn was obtained by X-ray photoelectron spectroscopy (XPS). Surface cleaning/preparation immediately before HS-LEIS, including atomic oxygen treatment and annealing, played a critical role in these efforts. Surfaces treated with DMZ generally showed slightly higher Zn signals by LEIS. Using this methodology, a value of 4.59 OH/nm2 was found for fully hydroxylated fused silica. Both this result and those obtained at 500, 700, and 900 °C are in very good agreement with literature values.

CeO2 surfaces play decisive roles in heterogeneous catalysis of important processes. Here, we investigate adsorption and dissociation of water and migration of protons on internal surfaces of nanoscopic porous CeO2. Sorption and thermogravimetry confirm literature suggestions that the surface is hydrogenated to Ce3+ ions and protons H+. The following chemisorption is dissociative, yet weak, and physisorption sets in only at the very highest relative humidities, reflecting hydrophobic behaviour. We link sample conductivities to surface protonic conductances via a brick layer model and show that behaviours at high, intermediate, and low temperatures with, respectively, positive, close to zero, and negative apparent activation energies and pH2O^(1/2), pH2O^1, and pH2O^(3/2) dependences, can be attributed to different models of migration all within the chemisorbed layer, without contribution from physisorbed water. While CeO2 may special in this respect due to the effect of the hydrogenated surface, we believe the extended models of transport in the chemisorbed layer may apply also to other oxides. Unsaturated chemisorption may play an important role for CeO2 as catalyst in that the surface is left available for reactant molecules, still with availability of dissociated and mobile protons in the chemisorbed layer and electronic defects by Ce3+ in the surface.

Producción Científica, The use of nanomaterials as electrode modifiers permits the enhancement of electrode performance using a great variety of approaches, from electrocatalytic enhancement to the improvement of charge transfer processes. The control and understanding of the interaction between the modifiers and the electrode itself are of key importance for the final performance of the modified electrode. This becomes especially relevant in the case of nanostructured materials since their physical response is rarely trivial. In this work, we combined electrochemistry and atomic force microscopy (EC-AFM) to in-situ investigate the surface condition of electrodes modified with silver nanowires (AgNWs) during EC measurements for the first time. EC-AFM allows us to perform cyclic voltammetry and electrochemical impedance spectroscopy together with the assessment of the electrode surface directly in the electrolytic solution. On the other hand, the use of the Langmuir-Blodgett technique provides homogeneity and reproducibility to the electrode modification process. The electrochemical response of the modified electrodes has been found to strongly depend on the selected substrate, but also on the deposition procedure. This opens the path for a better understanding of electrode modification process, and also supports the viability of EC-AFM on open problems involving electrochemistry and surface science., MINECO-FEDER (RTI2018–097990-B-100), Junta de Castilla y León-FEDER (VA202P20), Programa EU-FEDER (CLU-2019–04), Unión Europea–NextGenerationEU y la Universidad de Valladolid (CONVREC-2021–23).

Applied surface science 613, 155891 (2023). doi:10.1016/j.apsusc.2022.155891, (K,Na)NbO$_3$ is a lead-free and sustainable ferroelectric material with electromechanical parameters comparable to Pb(Zr,Ti)O (PZT) and other lead-based solid solutions. It is therefore a promising candidate for caloric cooling and energy harvesting applications. Specifically, the structural transition from the low-temperature M$c$- to the high-temperature c-phase displays a rich hierarchical order of domains and superdomains, that forms at specific strain conditions. The relevant length scales are few tens of nanometers for the domain and few micrometers for the superdomain size, respectively. Phase-field calculations show that this hierarchical order adds to the total free energy of the solid. Thus, domains and their formation has a strong impact on the functional properties relevant for electrocaloric cooling or energy harvesting applications. However, monitoring the formation of domains and superdomains is difficult and requires both, high spatial and high temporal resolution of the experiment. Synchrotron-based time-resolved X-ray diffraction methods in combination with scanning imaging X-ray microscopy is applied to resolve the local dynamics of the domain morphology with sub-micrometer spatial and nanosecond temporal resolution. In this regime, the material displays a novel self-stabilization mechanism of the domain morphology, which may be a general property of first-order phase transitions., Published by Elsevier, Amsterdam

Microbial adhesion and formation of biofilms cause a serious problem in several areas including but not limited to food spoilage, industrial corrosion and nosocomial infections. These microbial biofilms pose a serious threat to human health since microbial communities in the biofilm matrix are protected with exopolymeric substances and difficult to eradicate with antibiotics. Hence, the prevention of microbial adhesion followed by biofilm formation is one of the promising strategies to prevent these consequences. The attachment of antimicrobial agents, coatings of nanomaterials and synthesis of hybrid materials are widely used approach to develop surfaces having potential to hinder bacterial adhesion and biofilm formation. In this study, epigallocatechin gallate (EGCG) is attached on p(HEMA-co-GMA) membranes to prevent the bacterial colonization. The attachment of EGCG to membranes was proved by Fourier-transform infrared spectroscopy (FT-IR). The synthesized membrane showed porous structure (SEM), and desirable swelling degree, which are ideal when it comes to the application in biotechnology and biomedicine. Furthermore, EGCG attached membrane showed significant potential to prevent the microbial colonization on the surface. The obtained results suggest that EGCG attached polymer could be used as an alternative approach to prevent the microbial colonization on the biomedical surfaces, food processing equipment as well as development of microbial resistant food packaging systems.

The adsorption and desorption of the system CO/Pt(111) and C6H6/Pt(111) at 300 K has been investigated with a pulsed molecular beam method in combination with a microcalorimeter. For benzene the sticking probability has been measured in dependence of the coverage θ. For coverages θ > 0.8 transient adsorption is observed. From an analysis of the time-dependence of the molecular beam pulses the rate constant for desorption is determined to be 5.6 s− 1. With a precursor-mediated kinetic adsorption model this allows to obtain also the hopping rate constant of 95.5 s− 1. The measured adsorption enthalpies could be best described by (199 − 77θ − 51θ2) kJ/mol, in good agreement with the literature values. For CO on Pt(111) also transient adsorption has been observed for θ > 0.95 at 300 K. The kinetic analysis yields rate constants for desorption and hopping of 20 s−1 and 51 s−1, respectively. The heats of adsorption show a linear dependence on coverage (131 − 38θ) kJ/mol between 0 ≤ θ ≤ 0.3, which is consistent with the desorption data from the literature. For higher coverage (up to θ = 0.9ML) a slope of −63 kJ/mol describes the decrease of the differential heat of adsorption best. This result is only compatible with desorption experiments, if the pre-exponential factor decreases strongly at higher coverage. We found good agreement with recent quantum chemical calculations made for (θ = 0.5ML).

The search for improved surface properties of engineering alloys is always a matter of interest. Herein, we introduce a surface treatment based on depositing a non-continuous layer of two-dimensional (2D) nanomaterials via a simple and scalable method. 2D nanosheets of hexagonal boron nitride (h-BN) and graphene nanoplatelets (GNP) were sprayed on mild steel, followed by mild heat treatment. The nanosheets are strongly attached to the surfaces and even diffused to submicron under the surface, as proved by various analytical techniques. The mechanical, tribological and corrosion evaluations show significant simultaneous enhancement in a set of surface properties. From the friction tests with sliding steel-steel tribo-pairs under dry conditions, the graphene treatment decreases the friction coefficient and wear area by 21% and 31%, respectively. Interestingly, it is revealed that under dry and lubricated conditions, graphene-doped h-BN exhibits outstanding anti-wear properties synergistically compared to stand-alone 2D materials. The possible wear mechanism is investigated and found to be based on the formation of a tribofilm This research is supported by projects PID2020-112846RB-C22 and ED431C 2020/10 funded by MCIN/AEI/10.13039/501100011033 and “NextGenerationEU/PRTR” and through the Xunta de Galicia, respectively. Dr M.J.G.G. also acknowledges the Xunta de Galicia (Spain) for the postdoctoral fellowship (reference ED481B-2019-015) at Bournemouth University (UK) SI

Supported palladium catalysts are the most active ones toward the complete oxidation of methane. However, the presence of relevant amounts of water hinders the catalytic activity and long-term stability, due to competition between methane and water for the active sites. Hence, understanding the inhibition effect of water on methane oxidation is mandatory to improve these catalysts. We present an in situ ambient pressure X-ray photoelectron spectroscopy study of methane oxidation on Pd/Al2O3 in presence and in absence of water. The inhibition effect of water is demonstrated by combining reactivity tests with electron microscopy and photoelectron spectroscopy measurements. In the presence of water, the redox activity of palladium decreases. Water competes with methane for the catalytically active sites, poisoning the surface with hydroxyl groups and hindering the generation of the coordinatively unsaturated palladium active sites. Multiple palladium oxide species displaying different reactivity are identified. A new cationic palladium species, assigned to adatoms, is detected, which shows higher reactivity with methane than particulate palladium oxide but also high inhibition by water., Applied Surface Science, 606, ISSN:0169-4332, ISSN:1873-5584

Modern aeroengines employ labyrinth seal systems to seal the clearance between the blade tip and surrounding engine casing. Understanding of the wear mechanism between labyrinth fins and abradable coatings on the casing is necessary to help the aeroengine achieve higher efficiency. In this study, multiple tests with different types of fin geometries are conducted on a high-speed test rig with a fin tip speed of 100m/s. Two motorized stages are used to simulate the axial movement of the labyrinth fin in an aeroengine. The wear mechanism is investigated over a range of incursion rates from 2μm/pass to 10μm/pass, with in-situ force and temperature measurements along with high-speed imaging recorded on the side in each case. The surface examination of the wear track is also employed by using microscopy post-test. The main abradable material removal mechanism is extruding from the fin side. Also, adhesion of abradable material to the fin is found in each test and the adhesion amount is affected by both fin geometry and incursion rate.

Publisher Copyright: © 2022 The Author(s) Laser surface texturing (LST) is a powerful technique for creating high quality micro-textured patterns with different shapes and sizes on metallic biomaterials. Textured surfaces may improve the interaction between bone and implant by increasing the surface contact area and thus promoting bone regeneration. The goal of this study was to explore Nd:YAG laser potential for texturing micro-scale pillars with pyramid geometry, with dimensions in a selected range, in a reproducible way. First, the design and texture of grooves were addressed, then proceeding to pillars. Two laser machining and marking strategies were investigated, and the consecutive laser processing strategy and continuous marking mode were selected due to the resultant smoother grooves. Then, a cross-hatched pattern was designed to texture a pillar pattern with targeted dimensions. Given the direct effect of the LST drawing and laser parameters on the texture dimensions, three mathematical models, one for each texture dimension (groove width, pillar width and pillar depth) were developed. These models are accurate tools for predicting the texture dimensions in the selected range and this LST approach was effective on creating well-defined, uniform and equally spaced surface textures on Ti6Al4V parts, in a reproducible way. A combination of drawing and laser parameters was selected for the target dimensions, also considering suitable wettability and roughness for biomedical applications.

Poor correlation between the results of in vitro testing and the subsequent in vivo experiments hinders the design of biomaterials. Thus, new characterisation methods are needed. This study used proteomic and histological techniques to analyse the effects of Ca-doped biomaterials in vitro and in vivo and verify the correlation between the two systems. The sol-gel route was employed to synthesise coatings functionalised with 0.5 and 5 wt% of CaCl2. Morphology of the coatings was examined using SEM; the Ca2+ ion release from the materials was ana-lysed by means of ICP-AES spectroscopy. The osteogenic and inflammatory responses were inspected in vitro in human osteoblasts (HOb) and TPH-1 monocytes. The in vivo experiments used a rabbit model. The nLC-MS/MS-based proteomic methods were utilised to analyse the proteins adhering to the material samples incubated with human serum or examine protein expression in the tissues close to the implants. Ca-doped biomaterials caused a remarkable increase in the adsorption of coagulation-related proteins, both in vitro (PLMN, THRB, FIBA and VTNC) and in vivo (FBLN1, G1U978). Enhanced affinity to these materials was also observed for proteins involved in inflammation (CO5, C4BPA, IGHM and KV302 in vitro; CARD6, DDOST and CD14 in vivo) and osteogenic functions (TETN, PEDF in vitro; FBN1, AHSG, MYOC in vivo). The results obtained using different techniques were well matched, with a good correlation between the in vitro and in vivo experiments. Thus, the proteomic analysis of biological responses to biomaterials in vitro is a useful tool for predicting their impact in vivo. This work was supported by Ministerio de Ciencia e Innovación (PID2020-113092RB-C21), University of the Basque Country UPV/EHU (MARSA21/07), Basque Government (PRE_2016_1_0141), Universitat Jaume I (UJI-B2021-25) and Generalitat Valenciana (APOSTD/2020/036, PROMETEO/2020/069). The authors would like to thank for technical and staff support provided by SGIker (UPV/EHU/ ERDF, EU), and the company GMI Dental Implantology SL for producing the titanium discs.

Biomolecular condensates are membraneless, intracellular organelles that form via liquid-liquid phase separation (LLPS) and have the ability to concentrate a wide range of molecules in the cellular milieu. These organelles are highly dynamic and play pivotal roles in cellular organization and physiology. Many studies also link the formation and misregulation of condensates to diseases such as neurodegenerative disorders and cancer. Biomolecular condensates represent a special type of colloids that actively interact with their environment to sustain physiological functions, due to which their misregulation may upset cell signaling, resulting in pathological states. In this review, we discuss the mechanisms underlying the formation, dynamics, and evolution of these biological colloids, with a special focus on their surface properties that are critical in their interaction with other components of the cell. We also summarize experimental approaches that enable the detailed characterization of the formation, interactions, and functions of these cellular colloidal organelles.

Lithium-selenium (Li-Se) batteries have recently attracted increasingly attentions due to the high electronic conductivity and volumetric capacity of Se. However, the low selenium utilization and inferior electrode kinetics hamper the practical application of Li-Se batteries. In this work, a MoSe2@CNT/GO hybrid interlayer modified polypropylene (PP) (MoSe2@CNT/GO-PP) separator is designed to realize high-performance Li-Se batteries. The MoSe2@CNT/GO interlayer not only facilitates fast kinetic process by catalyzing the conversion of Li2Se, but also has strong chemisorption of Li2Se. These largely improve the selenium utilization. As a result, the Li-Se batteries with MoSe2@CNT/GO-PP separators exhibit a high reversible capacity of 547.2 mAh g−1 after 300 cycles at 0.5C and an excellent rate capability of 390.2 mAh g−1 at 5C. This work provides a new insight for enhancing the electrochemical performance of Li-Se batteries via modifying the separator.

This work aims at the elucidation of the interfacial interactions established between an epoxy-amine coating and hot-dip galvanized (HDG) steel. The influence of the Zr-based conversion treatment of the substrate and the use of the Cu(II) additive on interfacial bonding is studied. To this purpose, an amine-functionalized molecule – diethylenetriamine (DETA) – is adsorbed. The complex multi-metal oxide surface of the Cu-modified Zr-based converted substrate is decomposed in derivative (simpler) systems. The resulting DETA-adsorbed model and multi-metal surfaces are investigated by X-ray photo-electron spectroscopy (XPS), and by examination of the N 1s peak, the interfacial bond density is determined. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is performed to discriminate between the different metal oxide contributions present on the substrate surface. Preferential adsorption of the DETA molecule on the zinc atoms is found on converted substrates. The interfacial bonding with the Cu cationic sites introduced by the copper additive is proven.

Periodic DFT calculations are performed to unravel the effect of the incorporation of Fe and Mn into the tung-stated zirconia catalyst, (WO3)x/ZrO2 (x = 1,3), in their electronic, geometric, and catalytic properties. Our results suggest that both Mn and Fe have a proclivity to occupy the same positions and thus both metals will compete for the same adsorption sites. The addition of Fe or Mn slightly destabilizes the WO3 monomer while stabilizes the (WO3)3 trimer. Hence, medium size clusters, which are the most catalytically active species, will be more sinter resistant in the presence of the promoters, leading to catalysts with longer lifetimes. The computed deprotonation energies evidence that the overall Bronstead acidity is increased upon the addition of the dopant atoms. It is proposed that the metals lead to a reduction of WZ and induce a local spin density imbalance.The function as redox initiators of these metals is confirmed. This work is supported by grant PID2020-114754GA-I00 funded by MCIN/ AEI/10.13039/501100011033 and funding provided by Gobierno Vasco-Eusko Jaurlaritza (IT1254-19). We also thank DIPC and SGI-IZO-SGIker (UPV/EHU) for the generous allocation of computa-tional resources. The authors thankfully acknowledge also the computer resources at MareNostrum and the technical support provided by Bar-celona Supercomputing Center (QHS-2021-3-0004). The authors acknowledge the Instituto Politecnico Nacional for the financial support received through project SIP-20221590. J.I.R. thanks SIP-IPN for financial support (projects SIP20210100 and SIP20221613). K.G.M.C. thanks CONACYT-Mexico for the doctorate fellowship (CVU: 745592).

Use of heterojunctions between two materials having favorable optical and electronic properties can lead to increased photon absorption and charge separation resulting in enhanced photo-electro-chemical energy conversion. In the present study, graphene monolayer nano-flakes are mixed with TiO2 nanoparticles to form nanocomposites having different weight percentages of graphene. The microstructural, morphological and structural properties of the composite samples are investigated using X-ray diffraction, Raman spectroscopy and transmission electron microscopy techniques. Raman studies carried out on samples annealed at different temperatures show the interfacial interaction between TiO2 and graphene, although Anatase TiO2 and graphene maintain their phase integrity. PEC measurements show higher photo-electro-chemical activity in TiO2-graphene nanocomposite at an optimized concentration (2.0 weight percent) due to increased surface area, higher optical absorption in the visible part of the solar spectrum and favorable carrier transport due to increased concentration of defect states and graphene acting as a charge carrier medium.

The interest in graphene (a carbon monolayer) adsorbed on metal surfaces goes back to the 60’s, long before isolated graphene was produced in the laboratory. Owing to the carbon-metal interaction and the lattice mismatch between the carbon monolayer and the metal surface, graphene usually adopts a rippled structure, known as moir´e, that confers it interesting electronic properties not present in isolated graphene. These moir´e structures can be used as versatile templates where to adsorb, isolate and assemble organic-molecule structures with some desired geometric and electronic properties. In this review, we first describe the main experimental techniques and the theoretical methods currently available to produce and characterize these complex systems. Then, we review the diversity of moir´e structures that have been reported in the literature and the consequences for the electronic properties of graphene, attending to the magnitude of the lattice mismatch and the type of interaction, chemical or physical, between graphene and the metal surface. Subsequently, we address the problem of the adsorption of single organic molecules and then of several ones, from dimers to complete monolayers, describing both the different arrangements that these molecules can adopt as well as their physical and chemical properties. We pay a special attention to graphene/Ru(0001) due to its exceptional electronic properties, which have been used to induce long-range magnetic order in tetracyanoquinodimethane (TCNQ) monolayers, to catalyze the (reversible) reaction between acetonitrile and TCNQ molecules and to efficiently photogenerate large acenes.

Passivation of dangling bonds at the cleaved mirror facet and its durability are fundamental features of semiconductor lasers to obtain reliable operation with a long device lifetime. The high non-radiative recombination activity of the surface states needs to be controlled to prevent the Fermi level pinning before the deposition of mirror coating materials. Here, we report the incorporation of plasma cleaning of the facet and ZnO film as a passivation layer for the fabrication of high-power semiconductor lasers. The Argon plasma cleaning process was investigated to eliminate surface contamination without damaging the cavity surface. The ZnO passivation films were systematically studied by varying the chamber pressure and sputtering power of the radio frequency (RF) sputter coating process. We obtained homogeneous and dense ZnO films with high surface quality and optical absorption coefficient of zero. By incorporating the optimum plasma cleaning and passivation layer parameters, GaAs-based laser devices with significantly improved catastrophic optical mirror damage (COMD) power were achieved. COMD threshold was increased from 11.9 W to 20.7 W. The life test results demonstrate no failure for facet cleaned and passivated devices for more than 500 h, confirming the long-term effectiveness of the process for actual device integration.

Precision-engineered components which operate in demanding conditions often require the application of hard coatings such as tungsten carbide (WC) to improve their functional properties. Following the coating deposition process, a surface finishing or machining operation is often required to correct the sizing or achieve adherence to geometrical tolerancing and surface finish requirements. Single point diamond turning (SPDT) is a widely used ultraprecision machining technique for the fabrication of high-end engineering components made up of ductile materials, making it a desirable technique as a post-coating machining or finishing process. In this study the machinability of hard CVD W/WC coatings with a hardness of 1120 ± 15 HV and a thickness of 100 μm using SPDT was investigated. Here we report the results of axial and transverse turning using a cutting speed of 600 rpm and feed rates of 1 and 5 μm respectively. Experimental results show that an Ra of 0.2 μm is achieved with a diamond tool having a 0.5 mm nose radius. Significant tool wear was observed at the rake/flank edge of the diamond tool due to the coating's hardness. Surface and cross-sectional analysis of the samples' machined areas revealed presence of adhesive and abrasive wear. The occurrence of material pile-up due to tool loading on the surface of the coating was investigated through the indentation technique which demonstrated the occurrence of material deformation contributing to the overall surface roughness.

An extensive study on using plant waste aqueous extracts as natural chemicals for in-situ synthesis of zinc oxide (ZnO) on cotton is presented. Reducing agents were prepared from green tea leaves (GT), pomegranate peels (PG), and staghorn sumac leaves (SsL) and drupes (SsD), and the alkaline medium from discarded wood ash. Zinc acetate was found to be more appropriate precursor than zinc nitrate. Formation of ZnO on cotton was confirmed by energy dispersive spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction analysis (XRD). The inductively coupled plasma mass spectrometry and X-ray fluorescence results showed the highest amount of ZnO on cotton was formed using PG and SsL extracts, which was also confirmed with scanning electron microscopy and UV/visible spectroscopy. The ZnO-functionalised samples exhibited excellent UV-blocking ability and different wetting properties (hydrophilic or hydrophobic) depending on the reducing agent used due to their different total phenolic content. This study shows that by choosing the plant waste source as a reducing agent for ZnO formation directly on cotton, the properties of cotton can be designed to be hydrophilic or hydrophobic with excellent UV-blocking properties. The XRD results of ex-situ synthesis prove that the short reaction time enables the formation of ZnO.

Stainless steels typically feature high toughness and good corrosion resistance. However, pitting corrosion can easily occur on stainless steel and the passivation film tends to be vulnerable under pressure or in brine environments. Metal corrosion is a long-standing challenge for the steel industry, forging a path to net-zero. Herein, by successive growth of a series of quantum confined nanocrystals such as quantum dots and nanorods with gradient band energy level alignment, high-performance photoelectrochemical cathodic protection for steel is demonstrated with remarkable mechanical and electrochemical stability. Under simulated solar light illumination, effective photoinduced protection can be realized for 304 stainless steel which enables long-term corrosion resistance in a 3.5 wt% NaCl solution. Unique nanotree-like structures and the quaternary material combination can store excess charges and release them gradually, enabling time-delay protection for metals after light excitation. Various promising functionalities as unique photoelectrodes can be envisioned arising from the proposed 3D nanotree morphology.

Designing high-efficiency electrocatalysts is of great significance to produce ammonia via electroreduction reaction of nitrogen (NRR). To this end, grain boundary catalysis (GBC) has emerged as a promising strategy experimentally. Herein, based on first principles calculations, we modeled the grain boundary (GB) structures of hexagonal boron nitride (h-BN), then 12 transition metal atoms (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Y, Zr, Mo, Ru, and Rh) were anchored on the GB structures to construct single-atom catalysts, the most ideal overpotential of NRR is as low as 0.13 V for Mo adatoms on GB. Additionally, more sophisticated situations in regard to h-BN GB were considered, meanwhile electronic structure analysis was also conducted. We found that, the configuration and density of GB can hardly influence the catalytic activity at GB, while the coordinated B bonded with Mo strongly modified the spin states and the bonding strengths within certain intermediates, leading to this excellent NRR catalytic activity. This work not only provides a new strategy for the development of highly efficient and stable NRR electrocatalysts, but also enhances the understanding on the origin of GBC.

A novel facile and eco-friendly procedure for fabrication of multifunctional antibacterial and ultraviolet (UV) protective cotton surface was presented, including premodification of cellulose fibres with a polysiloxane matrix, followed by green in situ biosynthesis of silver nanoparticles (Ag NPs) in the presence of sumac leaf extract as a reducing and stabilising agent. During the biosynthesis, face-centred cubic Ag NPs with an average size of 52–105 nm were generated on the cotton fibres. Increasing the concentration of the AgNO3 precursor resulted in increased concentration of Ag NPs of 50–11,000 mg/kg. The chemically modified cotton surface exhibited excellent antimicrobial and UV protection properties. The additive antibacterial activity of Ag NPs and sumac leaf extract showed biocidal activity against S. aureus even at the lowest Ag NP concentration of 50 mg/kg, and in the case of E. coli, biocidal activity was achieved at a concentration of 340 mg/kg. The presence of both Ag NPs and sumac leaf extract provided UV protection factor greater than 40, irrespective of Ag NP concentration. The increase in Ag NP concentration significantly improved the durability of the coating.

In a simulated in-situ experiment annular contacts of 6082-T6 aluminium alloy were first exposed to various degrees of fretting wear, before synchrotron X-ray CT and diffraction were applied to examine the extent and development of wear damage. The wear volumes measured and development of the wear rate were consistent with the mathematical wear model of Fillot, Iordanoff & Berthier. Thickness and porosity of the worn zone were measured and the contact area between wearing elements estimated. Developments of residual strain and tribologically transformed structure were investigated through X-ray diffraction. This study demonstrates, for the first time, the value and viability of observing and quantifying wear through combination of X-ray CT and diffraction opening a path towards in-situ observations of wear.

In this paper, the wettability contrast surfaces were prepared via modifier-free composite processing. Nickel particles were added in electrolytes to fabricate micro-nano hierarchical structures by magnetic field induced jet electrodeposition. Laser surface modification was used to selectively draw patterns on the coating surface. After aging in the air for 25 days, the coatings prepared by magnetic field induced jet electrodeposition exhibited superhydrophobic, and the patterns achieved hydrophilicity or hydrophobicity by different laser fluences. Moreover, the morphologies and chemical composition of micro-nano hierarchical structures were changed by different laser fluences. Micro melted spots and hydrophilic nickel oxide appeared on the coating surface after laser surface modification. The wettability of the coating was altered by hydrophobic nickel hydroxide hydroxylated from NiO and organic substances from the air. However, the micro-nano structures were damaged by laser surface modification and cannot adsorb organic substances from the air. In addition, the superhydrophobic coatings and the hydrophilic patterns were corrosion-resistant. Ecorr and jcorr were - 0.2607 V and 7.225×10-6 A/cm2, - 0.5078 V and 9.354×10-6 A/cm2, respectively. Thus, the modifier-free processing, which combines magnetic field induced jet electrodeposition and laser surface modification, offers potential in the areas of green preparation for wettability contrast surfaces.