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We introduce and demonstrate the concept of a multipixel detector integrated at the tip of an individual multicore fiber. A pixel consists here of an aluminum-coated polymer microtip incorporating a scintillating powder. Upon irradiation, the luminescence released by the scintillators is efficiently transferred into the fiber cores owing to the specifically elongated metal-coated tips that ensure efficient luminescence matching to the fiber modes. With each pixel being selectively coupled to one of the cores of the multicore optical fiber, the resulting fiber-integrated x ray detection process is totally free from inter-pixel cross talk. Our approach holds promise for fiber-integrated probes and cameras for remote x and gamma ray analysis and imaging in hard-to-reach environments.

Anodic layer growth during anodization is a well-known phenomenon, used to increase the thickness of the natural layer present on the surface of metals for corrosion resistance. In the case of pure aluminum and its alloys, the porous oxide layer leading to a regular structures with nanopores arrangements, which provides interesting corrosion resistance and mechanical performances. The most frequent electrolytes (sulfuric, oxalid or phosphoric acid) induce low current/voltage at direct or pulsed modes to elaborate the oxide layer according to the different electrochemical windows. If the anodic oxide film elaborated in the first moment is soluble into the electrolyte, a porous structure take place with pores oriented perpendicular to the metal surface. The formation of the barrier layer occurs at the interface between the metal and the porous layer, but is thin enough to allow a continuous ionic flow which lead to a continuous film growth. The present work deals with aluminum anodization in etidronic acid (HEDP) at very high voltages for aluminum 1050 and 2024 alloys. It appears that the oxide layer growth, studied by XRD and SEM pictures of cross section obtained by ionic polishing, differs clearly for the reason that pores formations not only starts from the barrier layer, but also at different locations such as the oxide layer/electrolyte interface. The final result consist in an oxide layer with excellent functional properties.

The trend in electron accelerators design consists in approaching the poles of the steering magnets close to the electron beam. This implies reducing the bore hosting the vacuum chamber and using very small diameter vacuum pipes [1]. The application of functional thin films by physical vapour deposition in such small diameter chambers becomes then very difficult. A new approach relies on copper electroforming to build the vacuum chamber onto a pre-deposited thin film coating [2]. In this method, unlike the usual process, the pipe is built from the inside out. An aluminium mandrel is coated with a functional thin film first, then by a copper film and finally followed by a thick electroplated copper (1-3mm) structural layer. The replacement of high-purity copper parts by electroformed ones may nevertheless lead to the incorporation of various impurities among which hydrogen, which is generated by solvent reduction and thus trapped into the coating. The aim of the present study is the evaluation of the effect of two main triggers, namely polarization wave modulation and copper electrolyte composition by the addition of organic additives. For this purpose, transient curves in response to pulsed currents have been studied for various cathodic current densities. Two main patterns have been observed as shown in figure 1a in the absence of additive. At low current densities, i.e. below 50 A/dm2, the potential increases rapidly and reaches an average constant value. For higher current densities, two characteristic plateaux can be observed: the first one corresponds to the faradic reduction of copper below the diffusion limit, and the second one, at higher potential, is attributed to the diffusion-limited range that is well known for promoting the hydrogen generation. When adding 33 mg/L of d-xylose, it is possible to reach higher current densities before the occurrence of the transition between the faradic reduction of copper, near the electrode, and the diffusion-limited mechanism. The d-xylose acts clearly by inhibiting the hydrogen discharge. Thank to this, four singular situations have been identified on the curves (marked by the stars on figure 1). They correspond to four pulse sequences (40A/dm2, Ton=20 ms), (40A/dm2, Ton=80 ms), (70A/dm2, Ton=20 ms), (70A/dm2, Ton=80 ms), which were used to prepare samples for characterization in terms of hydrogen outgassing by Thermal Desorption Spectroscopy (TDS) and X-Ray Diffraction (XRD) measurements. TDS experiments show two peaks (figure 2), corresponding to the release of hydrogen trapped into the copper under different forms. The temperature of desorption of the first peak (around 420°C for a ramp of 10K/min) corresponds well to hydrogen interstitial diffusion in the copper deposit [3]. The nature of the second peak (around 600°C) is not yet understood. [1] C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallen and W. Wan, "Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source", in Proceedings of IPAC, Richmond, USA (2015), p. 1840. [2] L. Lain Amador, P. Chiggiato, L. M.A Ferreira, V. Nistor, A. T. Perez Fontenla, M. Taborelli, W. Vollenberg, M-L Doche, J-Y Hihn “Development of copper electroformed vacuum chambers with integrated non-evaporable getter thin film coatings” Journal of Vacuum Science and Technology A, accepted. [3] Y. Fukai “Formation of superabundant vacancies in M–H alloys and some of its consequences: a review” Journal of Alloys and Compounds 356–357 (2003) 270–273. Figure 1

International audience; In this paper, we study the influence of annealing on the performance of Resistive Temperature Detectors made from Nickel thin films. The aimed application is heat flux sensing. The substrate is made of Borofloat glass with a Chromium adhesive layer. Several annealing temperatures between 150°C and 300°C are applied to this assembly. The thin films as deposited and after annealing are analyzed through SEM images. The evolution of the resistance and the temperature coefficient of the sensor are discussed. An annealing temperature is selected that ensures the repeatability of measurements.

The human amniotic membrane (hAM) is an attractive biomaterial for regenerative medicine, as it contains amniotic mesenchymal stromal cells (hAMSC), epithelial cells (hAEC) and growth factors. We examined the potential use of hAM in orthopaedic and maxillofacial bone surgery, integrating the requirements of current regulations regarding advanced therapy medicinal products (ATMP) in the European Union. Previous studies have described the potential osteodifferentiation of intact hAM during whole-tissue culture in osteogenic conditions. The present study aims to determine whether in vitro osteodifferentiation of hAM is needed in the context bone repair, and the influence of this process on tissue structure, cell phenotype and cell function. Different conditions (fresh or cultured hAM; intact or hAM-derived cells) were tested. Phenotypic and functional analyses were performed with standard approaches (cell culture and staining, histological and immunolabelling) as well as original approaches (tissue staining, energy dispersive X-ray and X-ray diffraction). In our study, non-osteodifferentiated hAM (i.e., fresh or native hAM) exhibited innate pre-osteoblastic potential. Osteodifferentiation of fresh hAM induced a change in tissue structure, cell phenotype and function. Therefore, we hypothesize that pre-osteodifferentiation may not be necessary, especially if it induces unwanted changes. To our surprise, in these osteogenic conditions, hAEC had a mesenchymal phenotype with osteocyte function, and even native synthesis of hydroxyapatite, focusing osteogenic potential mainly in this epithelial layer. In conclusion, in vitro osteodifferentiation by tissue culture does not appear to be necessary for hAM to be used as an innovative ATMP for bone repair.

International audience; Résumé - Cette étude se situe dans le cadre du développement de fluxmètres thermiques en microtechnologie. Ces fluxmètres consistent en deux résistances de platine déposées sur un substrat en verre. Dans une première partie, nous présentons le principe du fluxmètre et de la mesure de température. Dans une deuxième partie, nous présentons également les étapes de fabrication en salle blanche et les différentes températures de recuits étudiées. Nous présentons des résultats expérimentaux sur la variation de résistance observée selon les différentes températures de recuit et une analyse par Diffraction de Rayons X complétée par des images au microscope à balayage. Nous proposons comme hypothèse que la baisse de résistivité observée pour les faibles températures de recuit est due à l’amélioration du réseau cristallin et que la hausse observée pour les températures les plus élevées est due à la diffusion de la couche d’accroche en chrome dans le platine.

The presence of hydrogen in electroformed copper from two different acidic copper sulfate solutions was evaluated: an additive-free solution and a solution including a sugar. D-xylose addition is found to inhibit H incorporation and allows the use of higher cathodic pulses before the copper diffusion limited range starts. TDS experiments show that hydrogen is trapped in the copper samples in two different forms. Hydrogen diffused from copper vacancies was found on all samples at an outgassing temperature of around 450°C. For samples with long pulse times, an additional H2 outgassing peak was found at around 600°C. XRD measurements allowed us to determine the preferential orientation of the plated samples and to monitor lattice parameter evolution with increasing temperature

The parent compound 1,3-dithiane (L1) was reacted with CuI providing the 1D coordination polymer [{Cu(μ

The parent compound 1,3-dithiane (L1) was reacted with CuI providing the 1D coordination polymer [{Cu(μ2-I)2Cu}(μ2-L1)2] n (CP1), an isostructural compound [{Cu(μ2-Br)2Cu}(μ2-L1)2] n (CP2) was isolated upon treatment of CuBr with L1. In contrast, treatment of L1 with CuCl results in the formation of 2D polymeric [{Cu(μ2-Cl)2Cu}(μ2-L1)] n (CP3), in which each sulfur atom acts as a 4-electron donor. The 1D compounds [{Cu(μ2-X)2Cu}(μ2-L2)2] n (CP7, X = Br, and CP8, X = Cl) resulting from treatment of 2-methyl-1,3 dithiane (L2) with CuBr and CuCl are isostructural with their CuI homologue [{Cu(μ2-I)2Cu}(μ2-L2)2] n (CP5), reported previously. Using CuCN, a 2D CP of composition [{Cu(μ2-CN)2Cu}(μ2-L2)2] n (CP9) has been isolated. Complexation of 2-isobutyl-1,3-dithiane (L3) on CuI generates a 2D material [{Cu3(μ3-I)(μ2-I)2(μ2-L3)2}] n (CP10), incorporating the usual trinuclear μ3-I-capped Cu clusters as SBUs, whereas 2D-polymeric compounds [{Cu(μ2-Br)2Cu}(μ2-L3)2] n (CP11) and [{Cu(μ2-Cl)2Cu}(μ2-L3)2] n (CP12) were obtained with CuBr and CuCl. Treatment of 2-Me3Si-1,3-dithiane (L4) with CuX yields the series [{Cu2(μ4-X)(μ2-X)}(μ2-L4)] n (CP13-CP15). With 2-phenyl-1,3-dithiane (L5), the outcome of the reaction with CuI depends on the reaction conditions. Reaction with CuI in MeCN provides a 1D ribbon [{Cu(μ2-I)2Cu}(MeCN)2(μ2-L5)2] n (CP16), whereas treatment of CuI with L5 in hot EtCN yields 2D-polymeric[{Cu3(μ3-I)(μ2-I)2(μ2-L5)2}] n (CP17). A reversible phase transition from triclinic P1 to monoclinic P21/ m is observed when recording the structure of CP16 at five different temperatures in the 100-300 K range. Ligand L6 containing a ferrocenyl function at the 2-position was also probed as organometallic dithioether ligand. Reaction of L6 with 1 equiv of CuI produces the 0D dinuclear complex [{Cu(μ2-I)2Cu}(η1-L6)2(MeCN)2] (D1), whereas treatment with 2 equiv of CuI affords the novel 1D CP [{Cu(μ3-I)2Cu}(μ-L6)] n (CP18), in which both S atoms of one L6 molecule span two copper centers of the infinite (CuI) n ribbon. Some selected results of thermal analyses and luminescence measurements are also presented.

Ionic liquids containing pharmaceutically active ingredients (API-ILs) have been used to electrosynthesize polypyrrole (PPy) films. Two different cations have been investigated, imidazolium and cholinium, respectively. These cations have been paired with saccharinate, acesulfamate and ibuprofenate anions. Growth of polypyrrole films in neat imidazolium API-ILs, which are liquid at room temperature, was shown to be difficult due to their high viscosities even at higher temperature. Moreover, the use of IL containing ibuprofenate anions led to the formation of crystalline ibuprofen deposited onto the PPy surface. This has been ascribed to the formation of local acidity during pyrrole oxidation. Using aqueous solutions of the biocompatible cholinium API-ILs, thick films have been obtained. Differences in term of morphology and roughness have been evidenced by SEM, depending on the anion used. GDOES analysis showed the incorporation of anions into the whole polypyrrole film thickness with small enrichment near the surface. Finally, we demonstrated that drug release kinetics can be controlled both by application of different negative stimulus and the nature of the anion. Upon application of more negative potential, drug release rates increased. The calculated kinetic parameters have evidenced a diffusion regime without stimulus and a change to anomalous regime upon applied potential.

In this study, a polymer, prepared by crosslinking cyclodextrin (CD) by means of a polycarboxylic acid, was used for the removal of pollutants from spiked solutions and discharge waters from the surface treatment industry. In spiked solutions containing five metals, sixteen polycyclic aromatic hydrocarbons (PAH) and three alkylphenols (AP), the material exhibited high adsorption capacities: >99% of Co2+, Ni2+ and Zn2+ were removed, between 65 and 82% of the PAHs, as well as 69 to 90% of the APs. Due to the structure of the polymer and its specific characteristics, such as the presence of carboxylic groups and CD cavities, the adsorption mechanism involves four main interactions: ion exchange, electrostatic interactions and precipitation for metal removal, and inclusion complexes for organics removal. In industrial discharge waters, competition effects appeared, especially because of the presence of calcium at high concentrations, which competed with other pollutants for the adsorption sites of the adsorbent.

While aluminum alloys are widely used in industrial applications, their protection by anodization as surface treatment always requires a preparation step by alkaline or acid etching. In this paper, use of ultrasound during the acid etching step on the 2024 aluminum alloy was investigated. Etching rate, calculated as of weight loss, was measured under ultrasound irradiation, and compared to silent conditions. The etched surface was characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS) and X-Ray Diffraction (XRD). Surface treatment was performed up to the final anodization step samples, and their final properties were evaluated as a function of various pre-treatments, including acid etching under ultrasound. The main evaluation concerned anticorrosion properties through electrochemical tests: polarization measurements and electrochemical impedance spectroscopy (EIS) in NaCl solution. Finally, use of ultrasound irradiation during acid preparation induced a beneficial effect on the corrosion performance of the anodic layer.

The functionalization of fluorine-doped tin oxide (FTO) substrates by a pyrrole-based silane and subsequent electrodeposition of polypyrrole films on the modified substrates has been achieved. First, N-[3-(trimethoxysilyl)propyl]pyrrole (TMSP) was successfully grafted on FTO substrates as evidenced using X-ray Photoelectron spectroscopy and Glow Discharge Optical Emission Spectroscopy. Second, polypyrrole was electrochemically prepared onto silanized (PPy/TMSP/FTO) and non-silanized (PPy/FTO) substrates, using potentiostatic and potentiodynamic techniques, in order to study the effect of silanization on the polypyrrole growth. Cyclic voltammetry experiments indicated that the growth of the polypyrrole films and their electrochemical activity weren’t strongly affected by the presence of a silane layer. On the contrary, the morphology of the PPy films was very different with and without the layer of silane since PPy/TMSP/FTO films were strongly less rough and more uniform than PPy/FTO films. The morphology of these new films was also granular and composed of globules having a submicrometric size. The lower roughness of the PPy/TMSP/FTO films, compared to the PPy/FTO ones, affected their wettability leading to a lower surface energy and more hydrophobic behavior. The conductivity of the PPy films was proved to be higher on unmodified FTO substrates by using conductive AFM experiments. Finally, the improvement of the adhesion of the polypyrrole films onto the FTO substrate, thanks to the silanization, was evidenced by immersing the modified FTO substrates in water for several weeks.

Self-assembling of undecanthiol (C11SH) on polycrystalline gold was investigated under two different conditions. The kinetics of C11SH grafting was studied without and under high frequency ultrasound irradiation. Two electrochemical experiments were extensively carried out in order to determine electrochemical surface blocking of adsorbed layers as a function of grafting time: chronoamperometry in-situ monitoring and cyclic voltammetry. Interestingly, the grafting process is highly accelerated under sonication, and C11SH modified substrates of good quality are obtained after 3h' immersion under ultrasound irradiation. This would allow elaboration of high-quality alkanethiol modified samples within much shorter times. Water contact angle measurements and X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of adsorbed undecanthiol on the gold surface. A very close link between electrochemical blocking, surface hydrophobicity and species chemical grafting was established.

The continuous growth of the electronic equipment market has led to an increased amount of scraping that it becomes necessary to recover. A hydrometallurgical method for copper and precious metal recovery from e-waste must consist of a number of steps: leaching, ion separation and subsequent electrochemical re-deposition of the target metal. Although this task is achievable in aqueous solutions, it requires strong acid or cyanide solutions. The aim of the study is to develop a new environmentally benign process by using a Deep Eutectic Solvent (DES), a form of cheap and safe ionic liquid, as an electrolyte for both leaching and electrodeposition. The experiments were conducted in a mixture of choline chloride and ethylene glycol, under 20 kHz ultrasonic agitation. In optimized temperature and sonication conditions, the leaching rate of copper attains 65 mg/h cm 2 . An interesting feature is that, in this media, copper dissolves into the form of Cu(I) complex instead of Cu(II) complex, so that subsequent electroreduction of copper ions is energetically more favorable. Copper deposits obtained from Cu I -DES solution present a sand-rose cluster morphology inducing a large developed surface. Application of ultrasound during electrodeposition allows for grain size reduction and crystallographic texture modifications, compared to silent conditions.

International audience; Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ~405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also discussed.

International audience; Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy.

International audience; We show that nano-optical antennas are capable of controlling the luminescence induced by the absorption of x rays into matter. The x-ray-excited luminescence from a tiny scintillation cluster coupled to a horn nano-optical antenna is highly directed and determined by the antenna’s geometrical parameters. Directionality is sufficiently high to efficiently outcouple the x-ray-excited luminescence to a narrow single-mode optical fiber, thus enabling ultracompact fiber-integrated x-ray sensors. Our nano-optically driven approach offers the possibility of x-ray profiling and dosimetry in ultra-confined environments, opening up new avenues in the fields of x-ray imaging, as well as medical and industrial endoscopy. With this study, to the best of our knowledge, nano-optical antennas make a first key contribution to the development of x-ray sensing protocols and architectures.

International audience; Laser ablation of bulk target materials in liquids has been established as an alternative method for the synthesis of nanoparticles colloidal solutions mainly due to the fact that the synthesized nanoparticles have bare, ligand-free surfaces since no chemical precursors are used for their synthesis. InSb is a narrow band gap semiconductor which has the highest carrier mobility of any known semiconductor and nanoparticles of this material are useful in optoelectronic device fabrication. In this paper a bulk InSb target was ablated in deionized (DI) water or ethanol using a nanosecond (20ns) or a femtosecond (90fs) pulsed laser source, for nanoparticles synthesis. In all four cases the largest percentage of the nanoparticles are of InSb in the zincblende crystal structure with fcc lattice. Oxides of either In or Sb are also formed in the nanoparticles ensembles in the case of ns or fs ablation, respectively. Formation of an oxide of either element from the two elements of the binary bulk alloy is explained based on the difference in the ablation mechanism of the material in the case of ns or fs pulsed laser irradiation in which the slow or fast deposition of energy into the material results to mainly melting or vaporization, respectively under the present conditions of ablation, in combination with the lower melting point but higher vaporization enthalpy of In as compared to Sb. InSb in the metastable phase with orthorhombic lattice is also formed in the nanoparticles ensembles in the case of fs ablation in DI water (as well as oxide of InSb) which indicates that the synthesized nanoparticles exhibit polymorphism controlled by the type of the laser source used for their synthesis. The nanoparticles exhibit absorption which is observed to be extended in the infrared region of the spectrum.

International audience; The article presents the design, fabrication and characterization of platinum thin-film Resistance Temperature Detectors (RTDs)for heat flux sensing applications. The microfabrication process is described and the thin films are analysed by several methodsincluding SEM, XRD and profilometry. Estimation of experimental uncertainties is performed. The influence of annealing, selfheating,2-wire and 4-wire connections are studied. The analysis and experimental results show that the RTDs have a goodrepeatability when an annealing process is performed and a maximal injected current are used. A measurement uncertainty of0.14°C is achieved. The observed Temperature Coefficient Ratio is sufficient to ensure variation of the resistance in thetemperature range. The heat flux measurements made with the sensor are validated in a dedicated test bench and present agood repeatability.

International audience; Self-assembly of alkylphosphonic acids on stainless steel was investigated under different conditions. Four different alkylphosphonic acids exhibiting alkyl chain of various size were synthesized and studied: butylphosphonic acid (C4P), octylphosphonic acid (C8P), decylphosphonic acid (C10P), and hexadecylphosphonic acid (C16P). Electrochemistry experiments were extensively carried out in order to determine electrochemical surface blocking of adsorbed layers in function of grafting time. In term of surface blocking, an 8h modification time was optimal for all alkylphosphonic acids. Longer immersion times lead to degradation of adsorbed layers. For the first time, grafting of C16P was studied under high frequency ultrasound irradiation. Interestingly, grafting process is highly accelerated under sonication and well-covering C16P modified substrates are obtained after 1h of immersion under ultrasound irradiation. This would allow to elaborate high-quality alkylphosphonic acids modified samples within much shorter times. Water contact angles measurements and X-ray Photoelectrons Spectroscopy (XPS) confirmed presence of adsorbed alkylphosphonic acids on stainless steel surface. A very tight link between electrochemical blocking, surface hydrophobicity and species chemical grafting was established.

Hybrid sol–gel films have been prepared with diethoxydimethylsilane (DEODMS), methyltriethoxysilane (MTEOS) as a source of hydrolysable silane and tetra-propoxyzirconium (TPOZ) as a source of hydrolysable zirconium. In order to improve corrosion protection, an organic corrosion inhibitor: tetrachloro- p -benzoquinone (chloranil), has been incorporated into the sol–gel matrix. The effect of chloranil, added with various concentrations from 3 to 12 × 10 −4 M, on the sol–gel film morphology and composition has been examined by atomic force microscopy (AFM) and glow discharge optical emission spectroscopy (GDOES), respectively. Addition of high additive concentrations (>9 × 10 −4 M) strongly disorganised the sol–gel network. The anticorrosion properties of the doped sol–gel films have been characterised by electrochemical impedance spectroscopy (EIS) in chloride solution and have been compared to salt spray observations. Chloranil additions ( −4 M) have significantly increased the corrosion protection of the sol–gel layers for a long term.

Anodic layer growth on 2024 aluminium alloy at 70 °C, under 40 V, during 60 min, in 50 g L −1 di-sodium tetraborate solution containing di-sodium molybdate from 0.1 to 0.5 M (pH 10) is examined. Anodising behaviours strongly depend on additive concentration. Development of anodic films is favoured with weak molybdate additions ( 0.4 M), anodising behaviour becomes complex with the formation of a blue molybdenum oxide at the cathode. The growth of aluminium oxide is hindered. As the anodic layers are thinner, the Mo(+VI) incorporation significantly decreases. These two configurations implicate different corrosion performances in 5% sodium chloride solution at 35 °C. As the alkaline anodic layer formed with 0.3 M molybdate species is the thickest and the Mo incorporation is the more pronounced, its corrosion resistance is the highest. The effect of morphology and composition of anodic films on pitting corrosion is also discussed.

Molybdate species added to sulphuric acid influence the composition and morphology of the anodic layers formed on 2024 aluminium alloy. In acid media, molybdate ions form polyanions with Mo (+VI). During anodising, different molybdenum oxides are produced, depending on the molybdate concentration. For low molybdate concentrations, unstable molybdenum oxides with Mo between (+IV) and (+V) are principally formed. For high concentrations, these unstable species are also produced but the stable molybdenum oxide with Mo close to (+V) is principally formed. These different electrolyte elements incorporate at the electrolyte/oxide interface and inhibit the transfer of aluminium cations to the electrolyte. This incorporation depends on the molybdate concentration and increases when more stable molybdenum oxides are formed (i.e., at high concentrations). This induces a reduction of the dissolution at the electrolyte/oxide interface. The rate of porous layer growth increases and the diameter of pores decreases. In addition, as the Mo incorporation increases with the increase of molybdate concentration, the influence on porous layer morphology becomes more pronounced.

Electrolytes composed of sulphuric acid and corrosion inhibitors (molybdate or permanganate species) were proposed in order to replace chromic acid for the anodising of 2024 aluminium alloy. The electrochemical impedance spectroscopy (EIS) method was used to visualise the correlation between the corrosion performance in NaCl and the morphology of these new anodic layers. From an appropriate equivalent circuit, EIS parameters concerning the porous and barrier layers were detected. Their evolution during corrosion tests was discussed. The results indicate that the morphology and the corrosion resistance of anodic films formed in acid sulphuric with molybdate species remain unchanged. On the contrary, morphological properties of anodic films formed in presence of permanganate species are modified, favouring their corrosion performance. EIS analyses were completed with SEM technique.

Influence of oxalic acid (H2C2O4) addition to chromic acid (CrO3) has been examined for the anodising of Al 2024 alloy. Electrochemical tests have been revealed significant dependence on the oxalic acid concentration. The role of electrolyte temperature has also been studied. A beneficial effect has been observed concerning the increase of H2C2O4 addition and temperature. They have affected the oxide film growth, modifying the morphology and improving the corrosion performance of anodic films.

In order to replace hexavalent chromium in anodising processes, molybdate species have been used as corrosion inhibitors. This article describes effects of molybdate additions to sulfuric acid on the anodising of Al 2024 alloy. Different electrochemical techniques were employed to study electrolytes, anodic film growth and corrosion resistance. These analyses have shown modifications as a function of molybdate concentration. At low concentrations, anodic layer formation was hindered and corrosion performance of these oxide films was slightly improved. On the contrary, at high concentrations, anodic layer growth was promoted and corrosion resistance was significantly improved.

Specific attention was focused on the characterisation of pitting initiated in different anodic films formed on aluminium 2024 alloy. Polarisation test in NaCl solution was used to initiate pitting corrosion in anodic layers produced in chromic acid, sulphuric acid and sulphuric acid containing molybdate species. Characteristics of pits were investigated by optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and image analysis. From optical and SEM micrographs, morphology of pits initiated in the different anodic layers was qualitatively described. The image analysis allowed to characterise pits from quantitative point of view. From these results, corrosion performances of chromic, sulphuric and sulphuric/molybdate anodic layers could be discussed.

Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

International audience; Because of its physicochemical properties, hydrogen appears as an efficient source of energy for powering devices. Its abundance on earth and the simplicicty of the process needed for its extraction from water make this compound a promising solution for an increasing number of applications (energy production and storage, car industry, space, etc.). However, due to its unstable properties, a particular care must be dedicated to control gaseous leaks close to facilities using this resource. Surface Acoustic Wave (SAW) sensors consisting in Rayleigh-wave delay lines equipped with a sensitive overlay can be efficiently used to detect hydrogen. In this paper, we propose a SAW device exhibiting either pure palladium or palladium-yttrium alloy sensing area for the detection of hydrogen in standard environmental conditions. An X-ray diffraction analysis of these sensitive materials is also presented and correlated with the simultaneously acquired signal of our sensor. Mesurements of hydrogen in the 0.5-2 % concentration range diluted in nitrogen are presented. The effect of combining yttrium and palladium as sensing layer on the sensor response is reported and its interest for improving our sensor's sensitivity is finally discussed.

In order to replace hexavalent chromium in anodising process, cerium IV and molybdate ions have been identified as corrosion inhibitors. This paper describes the effect of molybdate and cerium IV species added to sulfuric acid on anodic film formation on the 2024 aluminium alloy. Both voltammetric and chrono-potentiometric techniques have been used to investigate the electrochemical behaviour of the system and to determine the role of these compounds on film formation. The results obtained have indicated that oxide films growth has been promoted in the presence of cerium IV ions and has been hindered with molybdate ions.

Most oxide films provide extensive corrosion inhibitors by incorporation of chromium compounds (i.e. Cr(VI)) that provide such good protection. But, replacement of hexavalent chromium is also under active consideration because of its toxicity. This paper describes research, which has been carried out to find alternatives to chromic acid anodisation (H 2 CrO 4 ), for 2024-aluminium alloy. Promising inhibitors: molybdate and permanganate anions have been identified. In this work, attempts have been made to incorporate these inhibitors into the anodic film during the anodising process. Corrosion performance has been studied and compared using anodic polarisation techniques and impedance spectrometry measurements.

International audience; An acid Cu–Sn deposition bath was developed, and copper and copper–tin coatings were electrodeposited on polycrystalline platinum. The effect of gelatin on copper and copper–tin electrodeposition from acid sulfate solutions has been investigated by a variety of electrochemical methods (voltammetric studies and electrochemical quartz crystal microbalance) as well as by morphologic technique (scanning electron microscopy). The electrochemical results have shown that the overpotential is required when gelatin is added, indicating the presence of interaction between the additive and the coating. From the results of X-ray photoelectron spectroscopy, PM-IRRAS and cyclic voltammetry, gelatin was found to react with metal ions and platinum substrate. Adsorption of gelatin on the coating and platinum substrate is shown. Gelatin adsorption seemed to inhibit the initial nucleation of the copper and copper–tin electrodeposition, allowing homogeneous and smaller crystallites. Addition of gelatin was found to have an effect on reducing copper–tin alloys. The presence of gelatin impacts the crystal size and morphology of Cu–Sn deposits.

The electrochemical incorporation of a sulfonated cobalt phthalocyanine (sCoPc) in conducting polypyrrole (PPy) was done, in the presence or absence of LiClO4, in order to use the resulting hybrid material for the sensing of ammonia. After electrochemical deposition, the morphological features and structural properties of polypyrrole/phthalocyanine hybrid films were investigated and compared to those of polypyrrole films. A gas sensor consisting in platinum microelectrodes arrays was fabricated using silicon microtechnologies, and the polypyrrole and polypyrrole/phthalocyanine films were electrochemically deposited on the platinum microelectrodes arrays of this gas sensor. When exposed to ammonia, polymer-based gas sensors exhibited a decrease in conductance due to the electron exchange between ammonia and sensitive polymer-based layer. The characteristics of the gas sensors (response time, response amplitude, reversibility) were studied for ammonia concentrations varying from 1 ppm to 100 ppm. Polypyrrole/phthalocyanine films exhibited a high sensitivity and low detection limit to ammonia as well as a fast and reproducible response at room temperature. The response to ammonia exposition of polypyrrole films was found to be strongly enhanced thanks to the incorporation of the phthalocyanine in the polypyrrole matrix.

International audience; Laser ablation of a bulk Hf target in deionized (DI) water, ethanol, or toluene was carried out for the production of nanoparticles' colloidal solutions. Due to the interaction of the ablation plasma plume species with the species which are produced by the liquid decomposition at the plume-liquid interface, hafnia (HfO2) nanoparticles are synthesized in DI water, hafnium carbide (HfC) nanoparticles in toluene, and a mixture of these in ethanol. The hafnia nanoparticles are in the monoclinic low temperature phase and in the tetragonal and fcc high temperature phases. Their size distribution follows log-normal function with a median diameter in the range of 4.3–5.3 nm. Nanoparticles synthesized in DI water have band gaps of 5.6 and 5.4 eV, in ethanol 5.72 and 5.65 eV (using low and high pulse energy), and in toluene 3 eV. The values for the relative permittivity in the range of 7.74–8.90 were measured for hafnia nanoparticles' thin films deposited on substrates by drop-casting (self-assembled layers) in parallel plate capacitor structures.

Thrusting fault zone in foreland basins are characterized by highly foliated zones generally enriched in phyllosilicates which can play a major role on the mechanical behaviour of the fault. In this context, investigations of synkinematic clay minerals permit to determine the origin of the fluid from which they precipitated as well as the mechanisms of deformation. Our study is focused on clay mineral assemblages (illite and chlorite) in a major thrust fault located in the Monte Perdido massif (southern Pyrenees), a shallow thrust that affects upper cretaceous-paleocene platform carbonates and lower Eocene marls and turbidites. It implied 3 km of displacement of the Monte Perdido thrust unit with respect to the underlying Gavarnie unit. In this area the cleavage development by pressure-solution is linked to the Monte Perdido and Gavarnie thrust activity. The core zone of the fault, about 6 m thick, consists of an interval of intensely deformed clay-bearing rocks bounded by major shear surfaces. The deformed sediment is markedly darker than the protolith. Calcite-quartz shear veins along the shear planes are abundant. Detailed SEM and TEM observations of highly deformed fault zone samples indicate that clay mineral enrichment in the core zone of the fault is not only related to passive increase by pressure-solution mechanism but that dissolution–recrystallization of phyllosilicates occurs during deformation. A mineral segregation is observed in the highly deformed zone. Newly formed 2M 1 muscovite is present along the cleavage whereas IIb chlorite crystals fill SV2 shear veins suggesting syntectonic growth of phyllosilicates in the presence of fluids in low-grade metamorphic conditions. These mineralogical reactions act as weakening processes and would favour Monte Perdido fault creeping.

This paper presents the electrochemical synthesis of polyaniline films on fluorine tin oxide (FTO) and indium tin oxide (ITO) in acidic medium by both potentiodynamic and potentiostatic methods. The use of potentiodynamic deposition showed that conductive polyaniline films were synthesized by the same process than on noble metals and allowed the determination of the electrodeposition potential used for further potentiostatic electrodepositions. The electropolymerization was then performed by chronoamperometry and appeared easier on ITO than on FTO. The electrodeposited polyaniline films were extensively characterized in terms of chemical nature, electrochemical growth, thickness, roughness and morphology. The chemical nature of the films was identified through infrared spectroscopy and X-ray diffraction analyses. The roughness and the morphology of the polymer coatings, determined by profilometry, scanning electron microscopy and atomic force microscopy, were correlated to the calculated thickness of each polyaniline film and to the nature of the substrate.

International audience; One the way to improve the self-repair properties of sol–gel films on aluminium alloy is the addition of corrosion inhibitors which could be released from the coating, minimising the corrosion of the unprotected area. Environmentally friendly corrosion inhibitors are studied (chromium III, molybdate, permanganate and cerium III) and compared to the standard corrosion inhibitor, i.e. hexavalent chromium.Corrosion performances are studied by polarisation resistance (Rp) in chloride medium. Evolution of composition of sol–gel coatings, during the corrosion test, is examined by GDOES (glow discharge optical emission spectroscopy).The results show that the morphology of sol–gel and the solubility of the additive play a role in the effectiveness of corrosion protection for a long term. Additives such as molybdate and permanganate ions decrease the sol–gel network stability and are too soluble (they are rapidly lost from the sol–gel films, in an aggressive medium), decreasing the power to prevent corrosion. Incorporation of Ce III is not efficient for a long time due to its high solubility. Sol–gel films containing Cr VI and Cr III provide adequate corrosion protection, due to the sol–gel stability and their low solubility.