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International audience; Model intercomparison studies in the climate and Earth sciences communities have been crucial to building credibility and coherence for future projections. They have quantified variability among models, spurred model development , contrasted within-and among-model uncertainty, assessed model fits to historical data, and provided ensemble projections of future change under specified scenarios. Given the speed and magnitude of anthropogenic change in the marine environment and the consequent effects on food security, biodiversity, marine industries, and society, the time is ripe for similar comparisons among models of fisheries and marine ecosystems. Here, we describe the Fisheries and Marine Ecosystem Model Intercomparison Project protocol version 1.0 (Fish-MIP v1.0), part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), which is a cross-sectoral network of climate impact modellers. Given the complexity of the marine ecosystem, this class of models has substantial heterogeneity of purpose, scope, theoretical underpinning , processes considered, parameterizations, resolution (grain size), and spatial extent. This heterogeneity reflects the lack of a unified understanding of the marine ecosystem and implies that the assemblage of all models is more likely to include a greater number of relevant processes than any single model. The current Fish-MIP protocol is designed to allow these heterogeneous models to be forced with common Earth System Model (ESM) Coupled Model Intercompari-son Project Phase 5 (CMIP5) outputs under prescribed scenarios for historic (from the 1950s) and future (to 2100) time periods; it will be adapted to CMIP phase 6 (CMIP6) in future iterations. It also describes a standardized set of outputs for each participating Fish-MIP model to produce. This enables the broad characterization of differences between and uncertainties within models and projections when assessing climate and fisheries impacts on marine ecosystems and the services they provide. The systematic generation, collation, and comparison of results from Fish-MIP will inform an understanding of the range of plausible changes in marine ecosystems and improve our capacity to define and convey the strengths and weaknesses of model-based advice on future states of marine ecosystems and fisheries. Ultimately, Fish-MIP represents a step towards bringing together the marine ecosystem modelling community to produce consistent ensemble medium-and long-term projections of marine ecosystems.

International audience; In this study, a simple method to immobilize chitosan on a poly(lactic acid) (PLA) surface was developed in a fast manner. The immobilization was realized in two steps. First, an atmospheric plasma (MWAP) torch was used to modify the PLA surface in less than 5 min in order to create enough activated sites toward the chitosan adhesion, followed by a direct dip coating to spread and immobilize chitosan on this MWAP-modified PLA surface. The modification of the PLA surface properties was confirmed by X-ray photoelectron spectroscopy (XPS), water contact angle, and atomic force microscopy. It resulted that the activated species derived from the plasma torch, i.e., hydroxyl and carboxylic acid moieties, enabled an increase of the hydrophilicity of the PLA surface. Interestingly, this activated surface allows a good spreading of chitosan solution from dip coating and leads to a homogeneous stable coating. Our XPS results bring us the hypothesis that the stabilization of the chitosan layer is mainly induced by noncovalent interactions such as hydrogen bonding and electrostatic interactions. A first insight into the biological properties of theses surfaces was assessed in terms of the antimicrobial activity of the here-designed surfaces.

International audience; Novel BiOF/TiO2 heterostructures with controlled amounts of BiOF and TiO2 have been successfully synthesized via a simple solid‐state sintering method. The structural, morphological and optical properties were analyzed using several characterization techniques. A shift of the TiO2 absorption edge toward the visible region was observed. The optimal molar ratio of BiOF/TiO2 was found to be (1:3) with a photodegradation percentage of 91.2 % and it was 7 and 5 times more efficient than that of pure BiOF or TiO2 nanopowder, respectively. BiOF/TiO2 (1:3) heterojunction has showed high photodegradation stability for the Rh B photodegradation after three cycles. In the proposed photocatalytic mechanism, TiO2 absorbed the visible light and carried out the photocatalytic reaction owing to the decrease of its band gap value due to the formation of oxygen vacancies, while BiOF played an important role in the charge separation process due to the intimate contact of the BiOF/TiO2 heterojunction.

In this study, a novel simple and fast method was developed of immobilizing a natural polysaccharide (chitosan) on a polylactide (PLA) surface. In order to overcome the lack of surface adhesion between the chitosan and the PLA due to incompatibility issues, atmospheric pressure plasma was used. The plasma activation was able to modify the PLA surface by generating surface chemistry proper for stabilizing the chitosan layer. The activation of the surface was monitored through water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). Indeed, the introduction of new functionalities lowers the hydrophobicity of the PLA surface allowing an effective spreading and immobilization of the chitosan layer. The presence of chitosan on the polyester’s surface was proven by Fourier transform infrared spectroscopy (FTIR).

International audience; Vertically aligned multiwalled carbon nanotubes (v-CNTs) were functionalized with oxygen groups using low kinetic energy oxygen ion irradiation. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen ion irradiation produces three different types of oxygen functional groups at the CNTs surface: epoxide, carbonyl and carboxyl groups. The relative concentration of these groups depends on the parameters used for oxygen ion irradiation. Scanning electron microscopy (SEM) shows that the macroscopic structure and alignment of v-CNTS are not affected by the ion irradiation and transmission electron microscopy (TEM) proves tip functionalization of v-CNTs. We observed that in comparison to oxygen plasma treatment, oxygen ion irradiation shows higher functionalization efficiency and versatility. Ion irradiation leads to higher amount of oxygen grafting at the v-CNTs surface, besides different functional groups and their relative concentration can be tuned varying the irradiation parameters.

The control of the surface area enhancement and the ordering of the mesoporous photoanode is one of the key parameters to overcome the current limits of performance of dye sensitized solar cells (DSSCs). These parameters are expected to improve both the concentration of adsorbed dye molecules on the photoanode and the charge collection. In this paper, reactive magnetron sputtering at glancing angle is employed to synthesize nanostructured TiO2 thin films. A post-annealing treatment under an ambient atmosphere at 773 K allows recrystallization of the films to form individual single crystal-like anatase nanocolumns, as shown on a reference structure constituted by well-separated slanted nanocolumns. Even if the best cells provide an open circuit voltage of 0.8 V, a fill factor of 77%, and a short circuit current density of 4.6 mA/cm2 (JSC) and permit to reach an overall efficiency up to 2.6%, it does not yet reach the performances of the reference TiO2 nanoparticle (NP)-based cell. This is explained by a po...

6 pages, 5 figures, supporting information https://doi.org/10.1073/pnas.1900194116.-- All data reported in this paper are archived and publicly available at http://dataservices.gfz-potsdam.de/pik/showshort.php?id=escidoc:2956913., While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends, Financial support was provided by the German Federal Ministry of Education and Research through ISI-MIP (Grant01LS1201A1), the European Union’s Horizon 2020 Research and Innovation Program (Grant 678193), and the Ocean Frontier Institute (Module G). We acknowledge additional financial support as follows: to H.K.L., W.W.L.C., and B.W. from the Natural Sciences and Engineering Research Council (NSERC) of Canada; to D.P.T. from the Kanne Rasmussen Foundation Denmark; to A.B.-B. from the NSERC Transatlantic Ocean Science and Technology Program; to W.W.L.C. and T.D.E. from the Nippon Foundation-Nereus Program; to E.D.G., M.C. and J. Steenbeek from the European Union’s Horizon 2020 Re-search and Innovation Program (Grants 682602 and 689518); to E.A.F., J.L.B., andT.R. from Commonwealth Scientific and Industrial Research Organization and the Australian Research Council; to N.B., L.B., and O.M. from the French Agence Nationale de la Recherche and Pôle de Calcul et de Données pour la Mer; and to S.J. from the UK Department of Environment, Food and Rural Affairs

AuPd alloyed nanoparticles are regarded as very active catalysts for oxidation of alcohols. However we found that their catalytic activity can be further improved after calcination in air, which lead to the restructuring of alloyed AuPd nanoparticles and PdO segregation on the surface. The alloyed character was partially recovered upon reduction with H2 atmosphere, but the yet Pd‐rich surface was less active in the oxidation of the model molecule benzyl alcohol. 11;16

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International audience; Titanium-based thin films are synthesized by magnetron sputtering of a target heated under the ion bombardment. The effect on the deposition rate, microstructure/crystalline structure of the films and on the energy of the Ti condensing atoms onto the films are investigated. The deposition rate is increased by 1.6 and 6 in metallic and oxide regimes, the microstructure is modified, and the anatase phase is promoted in oxide regime as a result from the IR radiations (corresponding to 80% of the total energy here).

Titanium and silver atoms were magnetron-sputtered either onto pentaerythritol ethoxylate (PEEL) or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIMTFSI) ionic liquid (IL), and the formation of nanoparticles (NPs) is discussed based on the chemical interaction between the metal atoms and the host liquid. In the case of PEEL, our data reveal that titanium atoms sputtered in low-pressure argon plasma first form a film over the liquid surface. However, the latter dissolves as the film gets oxidized when vented to the air; asymmetric and faceted titanium dioxide NPs are finally obtained as if they were originating from a dismantled polycrystalline thin film. In the case of silver sputtered on PEEL, a film forms and solvation never occurs even after exposing the sample to air because the oxidation of silver is thermodynamically much less favorable than titanium. Quantum-chemical calculations confirm that the chemical interaction of TiO2 with PEEL molecules is favored as compared to metallic...

Hollow bimetallic nanostructures are of great importance for various applications. Understanding the fundamental mechanisms occurring during the synthesis of such nanomaterials by wet chemistry remains very challenging. This Article reports a mechanistic study on the galvanic replacement reaction between planar arrays of silver nanowires grown site-specifically on tall silicon nanogratings and HAuCl4 in lack of any stabilizing or capping agent, which might complicate and alter the conversion process of silver nanowires into silver–gold nanotubes. The direct contact of the silver nanowires with the substrate is found to modify the reaction as compared to nanowires in suspension. We show that when using diluted HAuCl4, AgCl nanoclusters precipitate on the surface during the process resulting in an increased surface roughness of the nanotubes. Overcoming this drawback requires saturating the HAuCl4 solution with NaCl; this allows distributing the anodic and cathodic sites over the surface of the nano-objects...

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A kinetic model describing the time evolution of ∼70 individual CO2(X1Σ+) vibrational levels during the afterglow of a pulsed DC glow discharge is developed in order to contribute to the understanding of vibrational energy transfer in CO2 plasmas. The results of the simulations are compared against in situ Fourier transform infrared spectroscopy data obtained in a pulsed DC glow discharge and its afterglow at pressures of a few Torr and discharge currents of around 50 mA. The very good agreement between the model predictions and the experimental results validates the kinetic scheme considered here and the corresponding vibration-vibration and vibration-translation rate coefficients. In this sense, it establishes a reaction mechanism for the vibrational kinetics of these CO2 energy levels and offers a firm basis to understand the vibrational relaxation in CO2 plasmas. It is shown that first-order perturbation theories, namely, the Schwartz-Slawsky-Herzfeld and Sharma-Brau methods, provide a good description of CO2 vibrations under low excitation regimes.

The covalent functionalization of exfoliated semiconducting MoS2 by 1, 2-dithiolanes bearing an ethylene glycol alkyl chain terminated to a butoxycarbonyl-protected amine and a photoactive pyrene moiety is accomplished. The MoS2-based nanohybrids were fully characterized by complementary spectroscopic, thermal, and microscopy techniques. Markedly, density functional theoretical studies combined with X-ray photoelectron spectroscopy analysis demonstrate preferential edge functionalization, primarily via sulfur addition along partially sulfur saturated zig-zag MoS2 molybdenum-edges, preserving intact the 2D basal structure of functionalized MoS2-based nanohybrids as confirmed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. Furthermore, in the MoS2-pyrene hybrid, appreciable electronic interactions at the excited state between the photoactive pyrene and the semiconducting MoS2 were revealed as inferred by steady-state and time-resolved photoluminescence spectroscopy, implying its high potentiality to function in energy conversion schemes.

In this work, we report on the development of a novel approach based on three different plasma-based processes (i.e., plasma polymerization, magnetron sputtering, and plasma etching) to fabricate nanostructured polymer thin films. Our strategy involves at first the formation of nitrogen containing plasma polymer film subsequently covered by silver nanoparticles, serving as a hard etching mask, using magnetron sputtering. Then, the exposition of the material to a complex mixture of highly reactive radicals, ions, and photons results in the structuring at the nanoscale of the functionalized plasma polymer films. It has been demonstrated that the dimension, the shape (e.g,. nano-dome, nano-cone, nano-valley, inter-connected porous network, …) and the chemical composition of the nano-objects can be tailored by adjusting the plasma parameters in each step of our overall procedure.

Site selective doping of aligned carbon nanostructures represents a promising approach for their implementation in actual devices. In the present work we report on alkali metals decoration on low density vertically aligned carbon nanotubes, disclosing the possibility of engineering site selective depositions of potassium atoms on the carbon systems. Photoemission measurements were combined with microscopy demonstrating the effective spatial control of alkali deposition. The changes of electronic structures of locally doped carbon regions were studied by exploiting the ability of the scanning photoemission microscopy technique. From the analysis of experimental data supported by theoretical calculations, we show the tuning of the charge transfer from potassium to carbon atoms belonging to neighboring nanotubes or along the same tube structure.

International audience; Herein, it is argued that Mars has nearly ideal conditions for CO 2 decomposition by non-equilibrium plasmas. It is shown that the pressure and temperature ranges in the ##IMG## [http://ej.iop.org/images/0963-0252/26/11/11LT01/psstaa8dccieqn1.gif] ∼ 96 % CO 2 Martian atmosphere favour the vibrational excitation and subsequent up-pumping of the asymmetric stretching mode, which is believed to be a key factor for an efficient plasma dissociation, at the expense of the excitation of the other modes. Therefore, gas discharges operating at atmospheric pressure on Mars are extremely strong candidates to produce O 2 efficiently from the locally available resources.

International audience; The interaction and charge transfer between Zn-based nanoparticles (NPs) and carbon nanotubes (CNTs) is investigated by X-ray Auger and photoelectron spectroscopy. Charge transfer from Zn NPs toward the CNTs is demonstrated by the presence of an additional feature revealed in the C 1s spectrum of CNTs. This charge transfer was found to vanish after thermal oxidation due to the transformation of the metal Zn into ZnO. Photoluminescence (PL) spectroscopy shows that in the samples ZnO(Nps)/CNTs the PL intensity is quenched. (C) 2013 Elsevier Ltd. All rights reserved.

International audience; CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst mode from 100% (i.e. corresponding to pure AC mode) to 40% leads to a rise in the conversion from 16–26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst mode remains constant as a function of the process time for the duty cycles

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Controlling the porosity, the shape, and the morphology of Kirkendall hollow nanostructures is the key factor to tune the properties of these tailor-made nanomaterials which allow in turn broadening their applications. It is shown that by applying a continuous oxidation to copper nanowires following a temperature ramp protocol, one can synthesize cuprous oxide nanotubes containing periodic copper nanoparticles. A further oxidation of such nanoobjects allows obtaining cupric oxide nanotubes with a bamboo-like structure. On the other hand, by applying a sequential oxidation and reduction reactions to copper nanowires, one can synthesize hollow nanoobjects with complex shapes and morphologies that cannot be obtained using the Kirkendall effect alone, such as necklace-like cuprous oxide nanotubes, periodic solid copper nanoparticles or hollow cuprous oxide nanospheres interconnected with single crystal cuprous oxide nanorods, and aligned and periodic hollow nanospheres embedded in a cuprous oxide nanotube. The strategy demonstrated in this study opens new avenues for the engineering of hollow nanostructures with potential applications in gas sensing, catalysis, and energy storage.

Nanoporous materials are of great interest for various technological applications including sensors based on surface-enhanced Raman scattering, catalysis, and biotechnology. Currently, tremendous efforts are dedicated to the development of porous one-dimensional materials to improve the properties of such class of materials. The main drawback of the synthesis approaches reported so far includes (i) the short length of the porous nanowires, which cannot reach the macroscopic scale, and (ii) the poor organization of the nanostructures obtained by the end of the synthesis process. In this work, we report for the first time on a two-step approach allowing creating highly ordered porous gold nanowire arrays with a length up to a few centimeters. This two-step approach consists of the growth of gold/copper alloy nanowires by magnetron cosputtering on a nanograted silicon substrate, serving as a physical template, followed by a selective dissolution of copper by an electrochemical anodic process in diluted sulfuric acid. We demonstrate that the pore size of the nanowires can be tailored between 6 and 21 nm by tuning the dealloying voltage between 0.2 and 0.4 V and the dealloying time within the range of 150-600 s. We further show that the initial gold content (11 to 26 atom %) and the diameter of the gold/copper alloy nanowires (135 to 250 nm) are two important parameters that must carefully be selected to precisely control the porosity of the material.

Nanoporous materials are of great importance for a broad range of applications including catalysis, optical sensors and water filtration. Although several approaches already exist for the creation of nanoporous materials, the race for the development of versatile methods, more suitable for the nanoelectronics industry, is still ongoing. In this communication we report for the first time on the possibility of generating nanoporosity in silver nanocolumns using a dry approach based on the oxidation of silver by direct exposure to a commercially available radio-frequency air plasma. The silver nanocolumns are created by glancing angle deposition using magnetron sputtering of a silver target in pure argon plasma. We show that upon exposure to the rf air plasma, the nanocolumns transform from solid silver into nanoporous silver oxide. We further show that by tuning the plasma pressure and the exposure duration, the oxidation process can be finely adjusted allowing for precisely controlling the morphology and the nanoporosity of the silver oxide nanocolumns. The generation of porosity within the silver nanocolumns is explained according to a cracking-induced oxidation mechanism based on two repeated events occurring alternately during the oxidation process: (i) oxidation of silver upon exposure to the air plasma and (ii) generation of nanocracks and blisters within the oxide layer due to the high internal stress generated within the material during oxidation.

International audience; In this experimental study, a flowing dielectric barrier discharge operating at atmospheric pressure is used for the splitting of CO2 into O2 and CO. The influence of the applied frequency and plasma power on the microdischarge properties is investigated to understand their role on the CO2 conversion. Electrical measurements are carried out to explain the conversion trends and to characterize the microdischarges through their number, their lifetime, their intensity and the induced electrical charge. Their influence on the gas and electrode temperatures is also evidenced through optical emission spectroscopy and infrared imaging. It is shown that, in our configuration, the conversion depends mostly on the charge delivered in the plasma and not on the effective plasma voltage when the applied power is modified. Similarly, at constant total current, a better conversion is observed at low frequencies, where a less filamentary discharge regime with a higher effective plasma voltage than that at a higher frequency is obtained.

In this work, we report on the Kirkendall-induced hollowing process occurring upon thermal oxidation of gold–copper (Au–Cu) alloy nanowires and nanodots. Contrary to elemental metals, the oxidation reaction results in the formation of gold nanostructures trapped inside hollow copper oxide nanoshells. We particularly focus on the thermally activated reshaping mechanism of the gold phase forming the core. Using scanning transmission electron microscopy coupled to energy dispersive X-ray spectroscopy mapping, we show that such a reshaping is a consequence to the reorganization of gold at the atomic level. The gold nanostructures forming the core were found to be strongly dependent on the chemical composition of the alloy and the oxidation temperature. By selecting the appropriate annealing conditions (i.e., duration, temperature), one can easily synthesize various heteronanostructures: wire-in-tube, yolk–shell, oxide nanotubes embedding or decorated by Au nanospheres. The advanced understanding of the Kirken...

International audience; Plasma processes are an innovative approach for the decomposition of CO2 in O radicals and CO as a valuable carbon source. In this experimental work, a tubular dielectric barrier discharge operating at atmospheric pressure has been used to split CO2 and study its conversion considering the influence of frequency and power, as well as the influence of various electrical regimes (AC, AC pulsed regimes). The CO2 conversion has been measured by mass spectrometry and gas chromatography while gas and walls temperatures have been determined and correlated to evaluate their influence of the CO2 splitting.

Communication par affiche; International audience; During the last decade, high power impulse magnetron sputtering (HiPIMS) has attracted a widespread interest in the scientific community because of substantial improvements over conventional pulsed direct current magnetron sputtering (DCMS). HiPIMS is utilizing high peak power densities of typically several kilowatts per square centimeter at a low repetition frequency. The specific sputtering regime in HiPIMS mode might allow the production of a dense ionized metallic vapor, which is not the case with pulsed DCMS. Some authors report a ratio of ionized species over 70 % in HiPIMS processes. This ratio, obviously, depends on numerous experimental parameters of the process deposition, but also of the sputtered target nature.This study focuses on the observation of the HiPIMS post-discharges using three different sputtering targets (Pd, Pt, Au) and different noble gases (Ne, Ar, Kr, Xe). The diagnosis of post-discharge is mainly achieved by the combined use of a mass spectrometer (MS), a retarded field energy analyzer (RFEA) and a polarized quartz crystal balance (PQB). The ion/neutral ratio is given for all target materials and plasma gases. In fine, part of time resolved ion energy distribution functions (IEDFs) is also given for multiple discharge conditions

Understanding the dealloying mechanisms of gold-based alloy thin films resulting in the formation of nanoporous gold with a sponge-like structure is essential for the future design and integration of this novel class of material in practical devices. Here we report on the synthesis of nanoporous gold thin films using a free-corrosion approach in nitric acid applied to cosputtered Au-Cu thin films. A relationship is established between the as-grown Au-Cu film characteristics (i.e., composition, morphology, and structure) and the porosity of the sponge-like gold thin films. We further demonstrate that the dealloying approach can be applied to nonhomogenous Au-Cu alloy thin films consisting of periodic and alternate Au-rich/Au-poor nanolayers. In such a case, however, the dealloying process is found to be altered and unusual etching stages arise. Thanks to defects and column boundaries playing the role of channels, the nitric acid is found to quickly penetrate within the films and then laterally (i.e., parallel to the film surface) attacks the nanolayers rather than perpendicularly. As a consequence to this anisotropic etching, the Au-poor layers are etched preferentially and transform into Au pillars holding the Au-rich layers and preventing them against collapsing. A further exposure to nitric acid results in the collapsing of the Au-rich layers accompanied by a transition from a multilayered to a sponge-like structure. A scenario, supported by experimental observations, is further proposed to provide a detailed explanation of the fundamental mechanisms occurring during the dealloying process of films with a multilayered structure.

International audience; In the context of a universal search for alternatives to chromate-based coatings, which are toxic for both human beings and the environment, a multilayer coating for Al protection purposes is developed and investigated in the current work. The first layer is selected to be a hexamethyldisiloxane-based plasma polymer film (PPF), deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD), due to a number of interesting features that are characteristic of plasma polymers. The second layer is synthesized via the polymerization of the 2-ethylhexyl acrylate monomer initiated from the free radicals trapped on the surface of the PPF during its growth. A subsequent layer of a copolymer of 2-ethylhexyl acrylate and glycidyl methacrylate, poly(EHA-co-GMA), is deposited by spin coating to increase the corrosion resistance of the coating. An improvement in the anti-corrosion properties of the multilayer coating by approximately three orders of magnitude as compared to the uncoated Al substrate is observed. Further enhancement of the adhesion and scratch resistance properties is addressed via UV-crosslinking and the incorporation of in situ generated silica nanoparticles into the final layer.

International audience; The total energy flux transferred to the substrate in sputter deposition experiments was varied in a broad range by modifying systematically the working conditions. A titanium target was sputtered in reactive atmosphere either in DC Magnetron Sputtering (DCMS) or in the High-Power Impulse Magnetron Sputtering (HiPIMS) mode. Unbalanced (UB) and balanced (B) cathodes were utilized and the time-averaged power delivered to the plasma was set to either 400 or 800 W. The total energy flux was measured in situ thanks to a heat flux sensor located at the substrate position. First, the energy flux exhibits a hysteresis when the oxygen inlet is increased and then decreased. In a second step, the normalized energy flux (φnorm) was calculated by taking into account the number of Ti atoms deposited per time unit and the discharge regimes were compared accordingly. Regardless of the sputtering method, the film phase constitution evolves from pure anatase to rutile rich anatase/rutile phase mixtures as φnorm is increased. φnorm is the highest for UB-HiPIMS configuration. A surprising result is that the energy flux related to the B-DCMS discharge at 800 W is higher than the one measured for the UB-DCMS, at the same power. The enhanced plasma confinement for the balanced cathode promotes the heating of the target surface. The contribution of the IR photon flux emitted by the hot surface to the total energy flux is significantly increased. From this result, it appears that this contribution should be taken into account when discussing thin film final features.

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International audience; The nanomanipulation of metal nanoparticles inside oxide nanotubes, synthesized by means of the Kirkendall effect, is demonstrated. In this strategy, a focused electron beam, extracted from a transmission electron microscope source, is used to site-selectively heat the oxide material in order to generate and steer a metal ion diffusion flux inside the nanochannels. The metal ion flux generated inside the tube is a consequence of the reduction of the oxide phase occurring upon exposure to the e-beam. We further show that the directional migration of the metal ions inside the nanotubes can be achieved by locally tuning the chemistry and the morphology of the channel at the nanoscale. This allows sculpting organized metal nanoparticles inside the nanotubes with various sizes, shapes, and periodicities. This nanomanipulation technique is very promising since it enables creating unique nanostructures that, at present, cannot be produced by an alternative classical synthesis route.

This paper presents a study on hydrogen sensing mechanism of Pd-loaded tungsten oxide (Pd–WO3). WO3 nanoparticles (sphere-like) were prepared and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. The synthesized WO3 nanoparticles was loaded with palladium (Pd) catalyst at 1 at% and annealed in air at 400 °C. The chemical composition of the elements and their spatial distribution on the surface were determined by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) respectively. Pd–WO3 thick film was prepared by screen-printing on alumina substrates fitted with gold electrodes and a platinum heater. The responses to 25–200 ppm hydrogen (diluted in air) were measured at operating temperatures ranging from 200 to 280 °C in dry air and with 50% relative humidity. The changes in the optical properties (on the surface) and crystal phases (in bulk) of Pd–WO3 in contact with hydrogen were investigated by UV–vis–NIR and XRD respectively. The in situ characterizations were carried out in different conditions, 3% H2 diluted in synthetic air/nitrogen at temperatures ranging from 25 to 200 °C. The changes in the crystal phases, formation of hydrogen tungsten bronze, on the surface or bulk were correlated with the electrical responses. A sensing mechanism of Pd–WO3 for H2 is proposed and discussed.

International audience; Functionalization of vertically aligned multiwalled carbon nanotube carpets was performed via exposure to CF4 or Ar:F2 RF plasmas. Rapid fluorination was observed via X-ray photoelectron spectroscopy (XPS) with surface fluorine concentration, bonding type, and patterning dependent on gas mixture and exposure time. Surface properties of the v-MWCNTs forests have been changed by the introduction of fluorine-containing groups, as demonstrated via surface wettability studies, while scanning electron microscopy shows that overall nanotube alignment and separation is conserved. Scanning X-ray photoelectron spectromicroscopy (SPEM) shows that the plasma treatment results in selective functionalization of the surface tips of the nanotubes. This opens the way to nanotube carpet structures with activated surfaces, which maintain the desirable conductive properties of the pristine nanotubes near to the substrate.

International audience; Highly ordered ultra-long oxide nanotubes are fabricated by a simple two-step strategy involving the growth of copper nanowires on nanopatterned template substrates by magnetron sputtering, followed by thermal annealing in air. The formation of such tubular nanostructures is explained according to the nanoscale Kirkendall effect. The concept of this new fabrication route is also extendable to create periodic zero-dimensional hollow nanostructures.

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