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Demonstrating the feasibility of constructing tunnels in deep clay formations is an important goal of the Belgian RD&D programme on the geological disposal of radioactive waste. In 2002 a major achievement was reached when the HADES Underground Research Laboratory (URL) in Boom Clay was extended with the construction of the Connecting Gallery. This demonstrated that it is feasible to construct galleries in poorly indurated clays using industrial techniques. To monitor the mechanical behaviour of the gallery and assess its stability, strain gauges were embedded in the segmental gallery lining and prisms were installed on the segments. These sensors provide valuable information that will support the design of future galleries. This paper presents 20 years of monitoring data in the Connecting Gallery and a first analysis of these data in terms of Boom Clay behaviour. In addition, the key findings are compared with those of a similar analysis performed by Andra (the French Radioactive Waste Agency) at the Meuse/Haute-Marne URL. The latter URL is excavated in the Callovo-Oxfordian claystone. The comparison identifies general trends and highlights similarities between the behaviour of tunnels in poorly indurated clay (Boom Clay) and in claystone.

Ce chapitre analyse les caractéristiques des cycles nucléaires ouvert et fermé (recyclage). Il aborde le monorecyclage et le multirecyclage de l’uranium et du plutonium. Il présente les coûts et modes de financement de la gestion des déchets pour l’entreposage de longue durée comme pour le stockage géologique profond (avec présentation de diverses expériences). Il aborde les incertitudes et risques des solutions retenues : fonds dédiés, provisions.

Macropatterned and micropatterned gold/silicon dioxide/titanium tungsten (Au/SiO2/TiW) substrates were orthogonally functionalized: three different molecules (monovalent silane, thiol, and phosphonic acid) were used to specifically form organolayers on Au, SiO2, or TiW areas of patterned substrates. The orthogonality of the functionalization (i.e., selective grafting of thiol on Au, phosphonic acid on TiW, and silane on SiO2) was assessed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements. These results are especially promising for the selective anchoring of targets (e.g., biomolecules, nanoparticles, nanowires, nanotubes, or other nano-objects) onto patterned zones of multimaterial substrates, such as nanosensors or other nanodevices.

International audience; The development of environmentally friendly materials and processes is a major issue that concerns all industrial sectors, including microelectronics. The aim of this study is to demonstrate the possibility of using chitosan-based photoresists for microelectronic applications on silicon by 193 nm photolithography. The photopatterning of chitosan films is demonstrated and analyzed by different spectroscopy and microscopy techniques. In particular, it is shown that 193 nm irradiation allows one to induce chain breaks that modify the solubility of chitosan in an aqueous developing solution, without denaturing the chitosan macromolecule chains. This mechanism allows one to obtain patterns, and it is shown that these patterns can be transferred by physical etching into silica. It is also demonstrated that the formulated resins are compatible with industrial spin-coating and exposure tools, which opens very interesting perspectives for these chitosan-based positive resins in a microelectronic context.

International audience; The production of hydrogen by efficient, low-cost, and integrated photoelectrochemical water splitting processes represents an important target for the ecological transition. This challenge can be addressed thanks to bioinspired chemistry and artificial photosynthesis approaches by designing dye-sensitized photocathodes for hydrogen production, incorporating bioinspired first-row transition metal-based catalysts. The present work r describes the preparation and photoelectrochemical characterization of a NiO photocathode sensitized with a phosphonate-derivatized ruthenium tris-diimine photosensitizer covalently linked to a cobalt diimine dioxime hydrogen-evolving catalyst. Under simulated AM 1.5G irradiation, hydrogen is produced with photocurrent densities reaching 84 +/- 7 mu A.cm(-2), which is among the highest values reported so far for dye-sensitized photocathodes with surface-immobilized catalysts. Thanks to the unique combination of advanced spectroscopy and surface characterization techniques, the fast desorption of the dyad from the NiO electrode and the low yield of electron transfer to the catalyst, resulting in the Co demetallation from the diimine dioxime framework, were identified as the main barriers limiting the performances and the stability of the system. This work therefore paves the way for a more rational design of molecular photocathodes for solar fuel production and represents a further step toward the development of sustainable processes for the production of hydrogen from sunlight and water.

Macropatterned and micropatterned gold/silicon dioxide/titanium tungsten (Au/SiO

International audience; he aim of this study is to investigate the degradation of hydrophobic coatings at the origin of reliability failure. Various properties such as adhesion and wetting after thermal ageing have been investigated. The layers studied, parylene C, Cytop and Fluoropel deposited on silicon wafers are widely used in electrowetting, MEMS and Lab-on-chip devices. A detailed failure mode analysis is presented, involving chemical surface modification through secondary ion mass spectroscopy by time of flight, X-ray photoelectron spectroscopy, surface energy and tensile strength measurements. We've been able to identify and quantify the origin of failure for each type of coating and the method we applied can be extrapolated to other hydrophobic coating as a benchmark for reliability improvement.

In previous work, textiles for the food processing industry were coated with an original deposition technique based on a combination of plasma-enhanced chemical vapor deposition and physical vapor deposition to obtain ~ 10 nm size silver clusters incorporated into a SiOCH matrix (Ag-SiOCH coating). However, the stability of the coating in end-use conditions (abrasion during washing cycles and/or oxidation) is questionable and this work is specifically devoted to study the effect on antimicrobial activity of Ag-SiOCH coatings after deposition of high porosity and low density protective layers. The Ag-SiOCH coating was thus covered with encapsulation layers (either hydrophobic SiOCH or hydrophilic AlxOy). The surface and bulk characterisation results of the multilayer coatings using X-ray Photoelectron Spectroscopy (XPS), Dynamic Secondary Ion Mass Spectrometry (DSIMS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) were used to study the composition of the coating and quantify the presence of the antimicrobial agent (Ag) at the surface and inside of the coating. Antibacterial tests indicated that antimicrobial activity of coated textiles was maintained. However, the antimicrobial activity was not directly correlated with the Ag content detected at the top surface or with the distance from the top surface to the part of the coating containing a significant amount of silver (as detected by XPS) and diffusion mechanisms during antibacterial tests could play a significant role. In particular, the hydrophilic character of AlxOy deposit likely allowed a better availability of the antimicrobial agent (Ag) but it was also observed for SiOCH hydrophobic deposits.

International audience; Understanding the structural and electronic factors governing the efficiency of dye-sensitized NiO photocathodes is essential to optimizing solar fuel production in photoelectrochemical cells (PECs). For this purpose, three different ruthenium dyes, bearing either two or four methylphosphonate anchoring groups and either a bipyridine or a dipyridophenazine (dppz) ancillary ligand, were synthesized and grafted onto NiO films. These, photoelectrodes were fully characterized by XPS, ToF-SIMS, and UV-vis absorption, time-resolved emission, and femtosecond transient absorption spectroscopies. Increasing the number of anchoring groups from two to four proved beneficial for the grafting efficiency. No significant modification of the electronic properties compared to the parent photosensitizer was observed, in accordance with the nonconjugated nature of the grafted linker. The photoelectrochemical activity of the dye-sensitized NiO electrodes was assessed in fully aqueous medium in the presence of an irreversible electron acceptor, and photocurrents reaching 190 mu A.cm(-2) were recorded. The transient absorption study revealed the presence of two charge recombination pathways for each of the sensitizers and evidenced a stabilized charge separated state in the dppz derivative, supporting its superior photoelectrochemical activity.

International audience; A current evolution of nanobiosensors stresses the interest of multi-material nanopatterned surfaces, for enhancing sensing performances. Besides, titanium tungsten (TiW) is mastered routinely implemented in nanoelectronic devices, in a reproducible way and at industrial production scales. Such material may be envisioned for being used in (bio)chemical nanoelectronic sensors, but the surface functionalization of such material has still to be studied. In the present article, orthogonal chemical functionalization of patterned Au on titanium tungsten (TiW) substrates have been explored for the first time to our knowledge. Surface functionalizations were assessed by X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection-absorption spectroscopy (PMIRRAS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging. Au/TiW patterned substrates were functionalized with mercapto-undecamine. Thanks to the orthogonality of thiol/Au versus phosphonic acid/TiW reactions, only Au features were modified leading to the amine derivatized surface. It allowed localizing carboxy-functionalized nanoparticles by electrostatic interaction on Au with a selectivity above 10 compared to TiW.

International audience; The aim of the this work was to study feasibility of titanium dioxide thin films prepared by atomic layer deposition (ALD) technique on aluminum foam substrates for photocatalysis and compare performance of thin films with commercially available AEROXIDE® TiO2. Formic acid and phenol photocatalytic decomposition was monitored using high-pressure liquid chromatography (HPLC). The morphology and thickness of TiO2 films were characterized by scanning electron microscopy (SEM) and their structure was determined by X-ray diffraction (XRD). Surface of the thin films was characterized with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The amount of TiO2 deposited on aluminum foam was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES). It was observed that initial rates of formic acid and phenol degradation were 0.007 and 0.001 mmol L−1 min−1, respectively. The apparent quantum yields for formic acid using immobilized and reference TiO2 powder (AEROXIDE® TiO2 P25, Evonik) were 2.2 and 2.7%, correspondingly. While for phenol apparent quantum yield was equal to 0.4% when TiO2 thin film was used and 0.7% in the case of reference powder. A decrease of the photocatalytic activity of TiO2 films deposited on aluminum foam was observed after the first cycle for both model compounds. It was suggested from this study that suppression of activity occurs due to detachment of TiO2 from the surface of thin film.

Chemical modifications of cellulose fibers as pretreatment for cellulose nanofibrils (CNF) production have been investigated to improve the production process and the quality of obtained cellulosic nanomaterial. In this study, phosphorylation of cellulose fibers was done in anticipation of a future nanofibrillation. Different phosphate salts, namely NH4H2PO4, (NH4)(2)HPO4, Na2HPO4, NaH2PO4 and LiH2PO4 with different constants of solubility (Ks) were used to increase the efficiency of the modification. Phosphorylated cellulose pulps were analyzed using elemental analysis, solid-state C-13 and P-31 NMR, or conductimetric titration method. No effect of Ks was observed whereas a counterion effect was pointed out. The study also reported the effect of pH, cellulose consistency, temperature and urea content in phosphorylation efficiency. Finally, chemical functionalization and penetration of phosphorylation reagents in the cellulose fibers were evaluated using XPS, SEM-EDX, ToF-SIMS and solid-state NMR.

International audience; To address all the concerns of organic electronics device development and especially ageing issues, analytical techniques must be able to provide extremely fine characterization of the composition and thickness of layers and interfaces, while retaining appropriate spatial resolution. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is able to provide a detailed characterization of the in-depth composition of hybrid organic/in-organic multilayer structures which is crucial for such investigations. The study of an aged AlQ(3) film after an exposition at the ambient atmosphere permitted to identify the secondary ions that are potentially indicative of the hydrolysis reaction of AlQ(3). The investigation of the organic/inorganic multilayer devices by ToF-SIMS depth profiling also confirmed a confinement of the moisture in the gas barrier layer(s). It was possible to determine the moisture ratio present in the different barrier architectures to compare the efficiency of the encapsulation. In particular, the double barrier layer has shown a lower and a more localized diffusion of the moisture in the barrier which was consistent with the results of the performance of the devices and with the data reported in the literature such as water vapor transmission rate ones.

International audience; Dye-sensitized photo-electrochemical cells (DS-PECs) form an emerging technology for the large-scale storage of solar energy in the form of (solar) fuels because of the low cost and ease of processing of their constitutive photoelectrode materials. Preparing such molecular photocathodes requires a well-controlled co-immobilization of molecular dyes and catalysts onto transparent semiconducting materials. Here we used a series of surface analysis techniques to describe the molecular assembly of a push-pull organic dye and a cobalt diimine-dioxime catalyst co-grafted on a p-type NiO electrode substrate. (Photo) electrochemical measurements allowed characterization of electron transfer processes within such an assembly and to demonstrate for the first time that a Co$^I$ species is formed as the entry into the light-driven H$_2$ evolution mechanism of a dye-sensitized photocathode. This co-grafted noble-metal free H$_2$-evolving photocathode architecture displays similar performances to its covalent dye-catalyst counterpart based on the same catalytic moiety. Post-operando time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of these photoelectrodes after extensive photoelectrochemical operation suggested decomposition pathways of the dye and triazole linkage used to graft the catalyst onto NiO, providing grounds for the design of optimized molecular DS-PEC components with increased robustness upon turnover.

International audience; Controlling and predicting the tribological behavior of dry lubricants is a necessity to ensure low friction, long life, and low particle generation. Understanding the tribochemistry of the materials as a function of the environment is of primary interest as synergistic effects exist between the mechanics, the physicochemistry, and the thermodynamics within a contact. However, in most studies the role of the coating internal contaminants in the process is often discarded to the benefit of a more common approach in which the performances of the materials are compared as a function of different atmospheric pressure environments. The study focuses on the understanding of the tribochemical processes occurring between the materials and their internal contaminants inside an AISI440C contact lubricated by a MoS2/Ti coating. Time-of-flight secondary ion mass spectrometry is used to study at the molecular level, the material before and after friction. Friction tests with different durations are performed in ultrahigh vacuum at the macroscale to stay relevant to the real application (space). The adsorption/desorption of gaseous species during friction is monitored by mass spectrometry to ensure reliable study of the tribochemical processes inside the contact. The study shows that a competition exists between the Ti- and MoS2-based materials to create the appropriate lubricating materials via (i) recrystallization of MoS2 materials with creation of a MoSxOy material via reactions with internal contaminants (presumably H2O), (ii) reaction of Ti-based materials with internal contaminants (mostly H2O and N-2). The biphasic material created is highly similar to the one created in both humid air and dry N-2 environments and providing low friction and low particle generation. However, the process is incomplete. The study thus brings insight into the possibility of controlling friction via a rational inclusion of reactants in a form of contaminants to control the tribochemical processes governing the low friction and long life.

Controlling and predicting the tribological behavior of dry lubricants is a necessity to ensure low friction, long life, and low particle generation. Understanding the tribochemistry of the materials as a function of the environment is of primary interest as synergistic effects exist between the mechanics, the physicochemistry, and the thermodynamics within a contact. However, in most studies the role of the coating internal contaminants in the process is often discarded to the benefit of a more common approach in which the performances of the materials are compared as a function of different atmospheric pressure environments. The study focuses on the understanding of the tribochemical processes occurring between the materials and their internal contaminants inside an AISI440C contact lubricated by a MoS

International audience; Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a high performance tool for molecular depth profiling of polymer films, in particular when they are structured in microphases. However, a major issue is the degradation of polymer materials under ion irradiation in reactions such as cross-linking, chain breaking, or reorganization processes of polymers which have been demonstrated for materials such as polystyrene (PS) and poly(methyl methacrylate) (PMMA). This work aims at comparing ToF-SIMS molecular depth profiling of structured polymers (polystyrene (PS)-b-polymethyl methacrylate (PMMA) block copolymers (BCP)) using either ultralow energy cesium or the more recently introduced C60(++) (under NO dosing and with sample cooling) and argon cluster ion beams (using Ar-1500(+) ions at 5 keV). The latter improved the quality of the depth profiles, especially the argon cluster ion beam, as it is characterized by a greater homogeneity for the sputter yields of PS and PMMA. No significant artifacts were observed, and this was confirmed by the comparison of depth profiles obtained from films with variable thickness, annealing time, and morphology (cylindrical blocks vs spherical blocks). Comparison to a theoretical model (hexagonal centered pattern) ensured that the ToF-SIMS depth profiles described the real morphology and may thus be a relevant characterization tool to verify the morphology of the films as a function of the deposition parameters

National audience

The aim of this paper is to report on the use of Microcontact Printing (μCP) for the manufacturing of 3D Molded Interconnects Devices. Two different approaches are reported. A first one is based on the total metallization of the polymer, μCP of the 3D pattern followed by the wet etching of the non-protected areas of the part (the so-called indirect process). A second approach is based on the combination of radio-frequency (RF) plasma treatment, μCP of a pattern of catalysts on the polymer and metallization by electroless deposition (the so-called direct process). This second process allows metallization of bare polymer parts (free of catalytic species in the bulk) with conductive 3D networks ready for the assembly of SMD devices. Examples of MID devices made with both approaches are reported. Key points like thickness (up to 12-15 μm), conductivity and adhesion of the metallic network are also reviewed. Printing on slope surfaces is demonstrated. Advantages and drawbacks of both processes are discussed.

International audience; The copper-mediated radical polymerization of N-acryloylmorpholine initiated from the surface of latex particles in water was studied to form hydrophobic core/hydrophilic shell particles. The latexes were synthesized via classical radical emulsion polymerization and were functionalized at their surface by a comonomer bearing a Br-functional group (the so-called inimer). The latter was introduced to initiate the grafting reaction, in the presence of the Cu(0)/CuBr2/PMDETA (1,1,4,7,7-pentamethyldiethylenetriamine) catalytic system. Conditions in which the grafting step could be performed at room temperature, using high particle concentration in the presence of surfactant and initiator remaining from the emulsion polymerization were identified. The success of the functionalization and grafting steps was evaluated by TOF-SIMS (time-of-flight secondary ion mass spectrometry), by FTIR, and by the final properties of the so-formed core shell particles. It is the first time such grafting conditions have been applied with success from "real latexes".

International audience; Polymer items are extensively present in the human environment. Humans may be consequently exposed to some compounds, such as additives, incorporated in these items. The objective of this work is to assess the human exposure to the main additives such as those authorized in the packaging for pharmaceutical products. The urinary matrix was selected to optimally answer this challenge because it has already been proven that the exposure to chemicals can be revealed by the analysis of this biological matrix. A multi-residue analytical method for the trace analysis at ng/mL in human urine was developed, and consisted of an extraction of analytes from urine by solid phase extraction (SPE) and an analysis by ultra-high performance liquid chromatography coupled to a tandem mass spectrometer (UHPLC–MS/MS). Even if the quantification of these compounds was an analytical challenge because of (i) the presence of these substances in the analytical process, (ii) the diversity of their physicochemical properties, and (iii) the complexity of the matrix, the optimized method exhibited quantification limits lower than 25 ng/mL and recoveries between 51% and 120% for all compounds. The method was validated and applied to 52 human urines. To the best of our knowledge, this work presents the first study allowing the assessment of the occurrence of more than twenty polymer additives at ng/mL in human urine.

Antimicrobial textiles (65% cotton – 35% polyester) were functionalized using a patented technology that combines an antimicrobial molecule – polyhexamethylene biguanide (PHMB) and a precipitating agent – sodium laurylsulphate. Surface characterization was performed by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, and both techniques made clear signatures of PHMB at the top surface of treated textiles. Washing led to a strong decrease of PHMB concentration at the surface. Comparison of textile surface analysis and antimicrobial tests indicated that the amount of PHMB at its extreme surface of textiles after five or 10 industrial washings was sufficient to inhibit Listeria innocua but not Pseudomonas aeruginosa growth. The viability of L. innocua cells after contact with PHMB-treated textile after one industrial washing was estimated using the Live/Dead BacLight kit (Molecular Probes, Eugene, OR): the combination of epifluorescence microscopy observations coupled with classic enumeration allowed detection of the presence of viable but nonculturable cells. PRACTICAL APPLICATIONS Protective clothing is required in the food-processing industry to protect products from being contaminated by microorganisms carried by workers' clothes or filtration systems. Consequently, there is an increasing interest in the use of antimicrobial functionalized textiles in the food industry to avoid that textiles could be vectors for pathogenic or food spoilage microorganisms. In the present study, the correlation between PHMB (the antimicrobial agent) at the surface of textiles (monitored by surface analysis characterization methods) and their antibacterial activity was assessed. After contact with antimicrobial textiles, the enumeration of bacteria was performed either by plate counting or by direct observation by epifluorescence microscopy in the presence of fluorescent viability markers in order to determine whether viable but nonculturable bacterial cells were present.

International audience; Textiles for the food industry were treated with an original deposition technique based on a combination of Plasma Enhanced Chemical Vapor Deposition and Physical Vapor Deposition to obtain nanometer size silver clusters incorporated into a SiOCH matrix. The optimization of plasma deposition parameters (gas mixture, pressure, and power) was focused on textile transparency and antimicrobial properties and was based on the study of both surface and depth composition (X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), as well as Transmission Electron Microscopy, Atomic Force Microscopy, SIMS depth profiling and XPS depth profiling on treated glass slides). Deposition conditions were identified in order to obtain a variable and controlled quantity of ~ 10 nm size silver particles at the surface and inside of coatings exhibiting acceptable transparency properties. Microbiological characterization indicated that the surface variable silver content as calculated from XPS and ToF-SIMS data directly influences the level of antimicrobial activity.

Polymer/metal nanocomposites films with different morphologies have been prepared from polyetherimide and palladium acetate with Pd amount ranging from 0 to 15 wt%. In a first step, hybrid precursor films have been obtained from polymer/metal complex solutions and the metal nanoparticles have been then generated within the PEI matrix by annealing the precursor film under different conditions. The membrane nanostructuration process and the final membrane morphology have been discussed as a function of the metal precursor amount and annealing conditions. The gas transport properties of the membranes have been analysed for CO 2 , He and H 2 . Specific interactions between hydrogen and the Pd based nanoparticles have been evidenced and the gas transport mechanisms have been discussed as a function of the gas nature, the nanoparticles structure and the nanoparticles location within the membrane.

International audience; An all-inorganic protocol, entirely based on wet chemistry methods, has been studied to form nanosized Ag metallic particles in solution Liquid suspensions of anatase TiO(2) nanocrystallites have first been prepared through a sal-gel route Silver nanoparticles (NPs) have then been generated through the photocatalytic reduction of a silver salt, diluted in TiO(2) liquid suspensions, and exposed to UV light, which results in the formation of a mixed Ag-TiO(2) suspension. Mechanisms occurring in solutions during the metallization step and a post-metallization ageing period have been studied by UV/vis spectroscopy Chemico-structural and morphological properties of resulting silver NPs have been studied by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Ag-TiO(2) suspensions have then been impregnated on cotton-based textile samples and the antibacterial activity of so-functionalized textiles has been studied with respect to E colt and L. innocua bacteria It is shown that, while TiO(2) NPs attached to textile fibres have no antibacterial activity, functionalized textiles exhibit a strong antibacterial activity due to Ag NPs, and this activity can be reached for a large range of impregnated silver amounts. (C) 2010 Elsevier B.V. All rights reserved

Textiles for the food processing industry are treated by a patented technology combining an ionic polymer (antimicrobial agent) and a precipitating agent to obtain an insoluble deposit expected to exhibit antimicrobial properties. ToF-SIMS and XPS are used in the understanding of the surface chemistry at various steps of treatments (cleaning step prior to surface modification, antimicrobial deposit, industrial ISO 15797 washing). ToF-SIMS and XPS analyses show that the signatures of the antimicrobial treatment are detected at the surface after treatment. After industrial ISO 15797 washings, the precipitating agent is rapidly removed (possibly replaced by washing agent components) while the antimicrobial agent (PHMB) is still detected but is significantly removed from the surface after five washings. ToF-SIMS and XPS data are compared to microbiological tests specifically intended in relation with food processing industry applications. After the antimicrobial treatment, the surface is biocide as well as after a single ISO 15797 washing, but after 5 washings, either the surface is slightly active (cotton-based textile) or not active anymore (polyester-based textile). The XPS N atomic percentage variation is unable to explain this difference. Even though a slight difference is observed for the ToF-SIMS normalized intensity for m/z = 184.1561 (PHMB molecular peak) between C/P and P/C samples, it can hardly be concluded that this would be the only explanation for the difference in activity. ToF-SIMS indicates that cotton is the textile component still detected at the surface of the washed samples. This could play a role in the remaining efficiency of the antimicrobial treatment after industrial washing.

Simple versatile processes combining plasma treatments, micro-contact printing (µCP) or ink-jet printing (IJP), and electroless deposition (ELD) have been developed to produce micrometer and sub-micrometer scale metal (Ni, Ag) patterns at the surface of polymer substrates. Plasma treatments were mainly used to graft the substrate surfaces with either nitrogen-containing functionalities on which a palladium-based catalyst can be subsequently chemisorbed (case of Ni deposition through a tin-free process in solution) or oxygen-containing functionalities on which a tin-based sensitization agent can be subsequently chemisorbed (case of Ag deposition through a redox reaction). µCP of the catalyst or of self-assembled monolayers (SAMs) as well as ink printing were used to obtain locally active or non-active areas at the polymer surfaces. The metal micro-patterns were characterized using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Surface chemical characterization wa...

TiO2:polymer bulk-heterojunctions (BHJ) have been elaborated from hydrolysis–condensation reactions of a TiO2 precursor in contact to the surrounding air humidity in a polymer thin film. A new precursor: tetrakis(9H-carbazole-9-yl-ethyl-oxy) titanium [Ti(OeCarb)4], has been synthesized as a TiO2 precursor to form a blend with Poly(N-vinylcarbazole) (PVK) which is the archetype of non-conjugated photoconducting polymer with strong electron-donor properties. This new precursor is expected to enhance the materials miscibility because of the chemical structure of the ligand close to the PVK repetitive unit and to inhibit premature hydrolysis by a strong steric hindrance. Commercial titanium isopropoxide [Ti(iOPr)4] was used as a reference to study the influence of the chemical structure of the precursor on BHJ properties. Photoluminescence studies have shown charge transfer enhancement when Ti(OeCarb)4 is used. In order to understand this ligand effect, photoluminescence (PL) responses were correlated with surface chemical composition (XPS) and topography (AFM) of thin films. Results have shown that Ti(OeCarb)4 allows a better miscibility between TiO2 and PVK. The lower reactivity of Ti(OeCarb)4 to hydrolysis and its chemical structure close to the repetitive unit structure of the polymer are believed to play a main role in the BHJ property improvement.

This paper deals with the extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1 used as a novel biosorbent to remove dye from aqueous solution in batch systems. As a widely used and hazardous dye, basic blue 54 (BB54) was chosen as the model dye to examine the adsorption performance of the EPS. The effects of pH, initial dye concentration, contact time and temperature on the sorption of BB54 to the EPS were examined. At various initial dye concentrations (50–400 mg/L), the batch sorption equilibrium can be obtained in only 5 min. Kinetic studies suggested that the sorption followed the internal transport mechanism. According to the Langmuir model, the maximum BB54 uptake of 2.005 g/g was obtained. Chemical analysis of the EPS indicated the presence of protein (30.9%, w/w) and acid polysaccharide (63.1%, w/w). Scanning electron microscopy (SEM) images showed that the EPS with a crystal-linear structure was whole enwrapped by adsorbed dye molecules. FTIR spectrum result revealed the presence of adsorbing groups such as carboxyl, hydroxyl and amino groups in the EPS. High-molecular weight of the EPS with more binding-sites and stronger van der Waals forces together with its specific construct leads to the excellent performance of dye adsorption. The EPS shows potential board application as a biosorbent for both environmental protection and dye recovery.

A conductometric enzyme biosensor using proteinase K was developed and then tested to relate its electrical signal to the number of proteinase K hydrolysis sites in bovine serum albumin (BSA) and angiotensin, a ten amino acid peptide, with one cleaving site.The conductometric sensor presents a large linear range of response for BSA and angiotensin ranging from 0.5 to 8 mg/l and from 4 to 8 mg/l, respectively. For a same tested concentration (mg/l), the response for native BSA is 12 times higher than for angiotensin. Aspartam was used as negative test and no response was obtained with the proteinase K biosensor. The conductometric sensor permitted also to detect difference on enzyme activity on native and non-native BSA, a response three times higher was obtained for non-native BSA. Keywords: Conductometric biosensor, Proteinase K, Bovine serum albumin, Angiotensin, Aspartam

Reliability and yield of nano-electronic devices can be seriously affected by the presence of surface contamination, even at low concentration. The microelectronics industry is, thus, in need for a quantitative, highly sensitive surface analysis technique capable of detecting both elementary and molecular species present at the surface. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provides a submicronic lateral resolution and excellent sensitivity with high secondary ion yields on a broad mass range but, nevertheless, remains a qualitative technique. To convert normalized ion intensities into concentrations and, thus, to provide reliable quantification, the so-called relative sensitivity factors (RSFs) need to be determined. In earlier studies, ToF-SIMS RSFs for trace metals were determined from the calibration of ToF-SIMS positive ion intensities against quantitative analysis techniques able to determine a surface coverage such as vapour phase decomposition inductively coupled plasma mass spectrometry (VPD-ICP-MS) or total reflection X-ray fluorescence (TXRF) results. Here, the aim is to quantify elementary anionic minority species (S, Cl, P, Br). Deliberately contaminated samples were prepared and analyzed with ToF-SIMS and several quantitative surface analytical techniques like TXRF, liquid phase extraction ionic chromatography (LPE-IC) or VPD-ICP-MS. None of these latter techniques can by itself successfully handle all the anionic species cases and ToF-SIMS turns out to be the more versatile and precise characterization technique in this context.

A bioflocculant TJ-F1 with high flocculating activity, produced by strain TJ-1 from a mixed activated sludge, was investigated with regard to its production and characterization. By 16S rDNA sequence and biochemical and physiological characteristics, strain TJ-1 was identified as Proteus mirabilis. The most preferred carbon source, nitrogen source and C/N ratio (w/w) for strain TJ-1 to produce the bioflocculant were found to be glucose, peptone and 10, respectively. TJ-F1 production could be greatly stimulated by cations Ca(2+), Mg(2+) and Fe(3+). The optimal conditions for TJ-F1 production were inoculum size 2 per thousand (v/v), initial pH 7.0, culture temperature 25 degrees C, and shaking speed 130r/min, under which the flocculating activity of the bioflocculant reached 93.13%. About 1.33 g of the purified bioflocculant, whose molecular weight (MW) was 1.2 x 10(5) Da, could be recovered from 1.0 l of fermentation broth. Chemical analysis of bioflocculant TJ-F1 indicated that it contained protein (30.9%, w/w) and acid polysaccharide (63.1%, w/w), including neutral sugar, glucuronic acid and amino sugar as the principal constituents in the relative weight proportions of 8.2:5.3:1. Scanning electron microscopy (SEM) image of the purified solid-state TJ-F1 showed that it had a crystal-linear structure. Spectroscopic analysis of the bioflocculant by Fourier-transform infrared (FTIR) spectrometry indicated the presence of carboxyl, hydroxyl and amino groups preferred for the flocculation process.

We report a new approach based on DNA hybridization for detecting HBV virus using non-faradic electrochemical impedance spectroscopy. DNA probes modified with biotin in 5′ position were immobilized on streptavidin modified magnetic nanoparticles by biotin–streptavidin interaction. A layer of functionalized nanoparticles was directly immobilized on bare gold electrode using a magnet. Before detection atomic force microscopy was used to visualize the layer of magnetic nanoparticles and cyclic voltammetry permitted to characterize DNA probe immobilization. The hybridization reactions with specific complementary DNA target and no complementary target were investigated by non-faradic impedance spectroscopy. Results show the good immobilization of the DNA probes and the hybridization with different concentrations of complementary DNA. Non-faradic impedance spectroscopy allows to detect 50 pmol of HBV DNA and 160 pmol of HIV DNA on sample of 20 μL. Saturations were reached for the same concentration 12.65 nmol/mL for a same quantity of immobilized DNA probes.

A hexavalent chromium-sensitive EMIS sensor (electrolyte membrane insulator semiconductor sensor) is prepared by deposition of a tributylphosphate (TBP) ionophore-containing siloprene membrane on a Si/SiO2/Si3N4 structure. The developed EMIS sensor was studied by means of impedance spectroscopy, capacitance–voltage, X-ray photoelectron spectrometry and FT-IR spectroscopy. From the flat-band shift of the EMIS structure, the nersntian response to the anionic species Cr2O7− was demonstrated. The linear range of detection is 10− 4 M to 10− 1 M and the detection limit is 10− 5 M. Sulfate and chloride anions are shown not to be interfering whereas carbonate ions present a pKpot equal to 0.19.

The necessity to adapt sensors based on electrochemical techniques for high throughput analysis control increases the interest to develop new analytical systems able to perform measurements under buffer flow. In this report we explored the possibility of employing a new system to make impedimetric measurements to detect the interaction between proteins and small molecules. The well-known biotin–streptavidin interaction was adopted to evaluate the proposed assembly. This system allows us to perform experiments under flow. Magnetic beads functionalized with streptavidin were used and first characterized using AFM and FTIR. Non-faradic impedance spectroscopy allowed the detection of the biotin–streptavidin interaction. Using our new system and under a flow of PBS buffer, 5 10− 5 M of biotin was detected with a stable signal.

Ion implanted Insulator-Semiconductor (IS) sensor that specifically detects Na+ ions have been developed using ion implantation technique. Na+ ions were directly implanted with ion energies 30, 45, and 60 keV into the IS (oxidized Si3N4/Si3N4/SiO2/P-Si) structures previously covered with a thin aluminum layer. X-ray photoelectron spectroscopy (XPS) characterization shows that sodium and aluminum ions were implanted into the oxidized Si3N4 insulating layer surface. Their atomic percentage depending on energy, fluence of the implanted ion and of the annealing temperature. The sen sitivity of the ion-implanted IS structure for Na+ and of some interfering (K+, Li+, H+, and NH4+) ions was investigated using high frequency capacitance-voltage measurements. Under optimal i mplantation conditions such as energy, fluence and annealing temperature, the developed sodium microsensor demonstrates quasi-nernstian sensitivity (50 +/- 2 mV/pNa) in the concentration range from 10(-3.7) to 10(-1) M and high lifetime greater than 16 months without any loss of sensitivity.

Recent time-of-flight secondary ion mass spectrometry (ToF-SIMS) studies using primary cluster ion sources such as Au n + , SF n + , Bi n + or C 60 + have shown polyatomic ions to be more appropriate for the detection of high mass molecular secondary ions than monoatomic ion sources like Ga + , thanks to secondary ion yield and ion formation efficiency enhancements. This work is part of a study aiming at improving molecular compound quantification at the surface of microelectronics industry substrates by taking advantage of a polyatomic ion source in ToF-SIMS analysis. It focuses on the case of a phthalate-related contamination. Fundamental parameters like secondary ion yield, damage cross section and secondary ion efficiency were studied as a function of the size and the energy of the primary ions. The substrate composition influence on the ToF-SIMS results was also studied by comparing several substrates of interest in the microelectronics industry such as silicon wafers and low dielectric constant materials 5iO x CyH z . Phthalate-related secondary ions detected at the surface of the contaminated surfaces were compared and a fragmentation pathway of the di-isononyl phthalate (DNP) molecule was determined. A drastic improvement of the secondary ion yield was provided when using a polyatomic ion source. Furthermore, a clear increase in damage cross section was observed as a function of the secondary ion size for a given Bi n primary ion as well as an increase for a given fragment as a function of the number of Bi atoms in the Bi n aggregate. This led to a lower static limit when taking into account higher phthalate fragments and primary ions of larger size.

Cast-hybrid films composed of polyvinyl alcohol (PVA) and silver nitrate were treated according to three different ways, thermal annealing, UV-irradiation, and chemical reduction by a borohydride solution, to obtain PVA/silver nanocomposite films. The nanostructuration process was studied as a function of the treatment conditions, and discussed as a function of the mobility state of the polymer chains in the nanocomposite matrix during treatment. A homogeneous dispersion of crystalline silver nanoparticles was obtained by thermal annealing above Tg and below Tm and UV-lamp irradiation below Tg. For these two treatments, the major processing parameters were the annealing temperature and time and the UV-exposure time, respectively. For low-conversion rate in Ag(0), the films evolved upon ageing at room temperature. Totally different morphology and Ag(0) conversion were achieved by chemical reduction in a borohydride solution. All the silver ions were reduced into Ag(0), and crystalline silver nanoparticles layers parallel to the film surface were observed after the treatment. This morphology was related to the high-swollen state of the polymer matrix during treatment. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2062–2071, 2008

A study on the synthesis of La 1− x Ag x MnO 3+ δ ( x = 0, 0.2) using a microwave process (MWhyd) has been carried out by comparing the heating time and reaction temperature with the same factor under conventional thermal process (CHhyd). Experiments have been conducted using the hydrothermal method at medium pressure ( T = 200 °C, P = 20 atm) followed by a thermal treatment of the precursor at 700 °C (10 h). Structural and physico-chemical properties of the catalysts were investigated using X-ray diffraction (XRD), BET sorption, temperature-programmed reduction or desorption, mass spectrometry (TPR-MS and TPD-MS), and X-ray photoelectron spectroscopy (XPS). While CHhyd and MWhyd powder catalysts exhibited the same XRD patterns indexed as pure perovskite structure, their surface physico-chemical properties were found to be strongly influenced by the preparation method. The effect of the nature of oxygen species, their amount and mobility, evidenced by temperature programmed experiments, on the catalytic properties in methane combustion in the presence and in the absence of hydrogen sulphide has been studied. MWhyd-La 0.8 Ag 0.2 MnO 3+ δ catalysts were found to exhibit a much better performance in methane combustion together with higher resistance to sulphur poisoning than CHhyd catalysts.

This study investigated the influence of the fluorine-based additive content on the physical and physicochemical properties of paraffinic wax. Nineteen mixtures of a paraffinic wax and a fluorine-based additive (0 to 50%) were characterised by penetrability tests at − 24 °C and + 24 °C and by static and dynamic wettability measurements. Three of them (4%, 8% and 50% content in the fluorine-based additive) were also characterised by X-ray Photoelectron Spectroscopy (XPS). The wettability and penetrability results significantly increased between 0% and 4%, then significantly decreased between 4 and about 10%, and remained constant from 10% to 50% of fluorine-based additive. Maximal water-repellence was observed for about 4% of the fluorine-based additive. The XPS results indicated that the increase in fluorine concentration at the mixture surface was not linearly related to the fluorine-based additive content in the paraffinic wax. These results pointed out that there is a limit in addition of the improvement of paraffinic wax properties as a function of the fluorine-based additive content.

International audience; Single-step orthogonal chemical functionalization procedures have been developed with patterned gold on silica surfaces. Different combinations of a silane and a thiol were simultaneously deposited on a gold/silica heterogeneous substrate. The orthogonality of the functionalization (i.e., selective grafting of the thiol on the gold areas and the silane on the silica) was demonstrated by X-ray photoelectron spectroscopy (XPS) as well as time-of-flight secondary ion mass spectrometry (ToF-SIMS) mapping. The orthogonal functionalization was used to immobilize proteins onto gold nanostructures on a silica substrate, as demonstrated by atomic force microscopy (AFM). These results are especially promising in the development of future biosensors where the selective anchoring of target molecules onto nanostructured transducers (e.g., nanoplasmonic biosensors) is a major challenge

SSCI-VIDE+CARE+DAG:CGU:IBE; International audience; Stability and photocatalytic efficiency of hybrid composite films obtained by efficient dispersion of anatase TiO2 nanoparticles in various hybrid silica matrices are investigated in order to address the structure/reactivity relationship. The photocatalytic activity is systematically monitored as a function of the chemical composition of the matrix at the molecular level, and thus the final structure of the material. The partial elimination of the organic groups brings by the organosilane precursors under UV exposure was followed by HPLC and by surface analysis (XPS, contact angle). The impact of the alkoxysilane structure on the final structure of the matrix is evaluated. In the same way, the impact of thermal and photonic pretreatments on the coating photocatalytic activity is evaluated using formic acid as model pollutant. Finally, the role of the remaining organic groups in the silica network on the structure modification and on the photocatalytic activity is investigated by varying their nature and ratio. Depolluting and self-cleaning activities of optimized coatings are studied by degrading formic acid and methylene blue in different conditions of pollutant concentration and photon flux. We interestingly show that in all cases, the presence of the organic groups in the matrix induces an increase in the photocatalytic efficiency. Finally, efficient photocatalytic flexible films are prepared and show promising photocatalytic degradation mechanism under low UV excitation, comparable to solar UV irradiation.Highlights• Composite coatings made of commercial TiO2 inserted into a hybrid silica matrix.• UV pretreatment is necessary to improve the photocatalytic efficiency.• Thermal treatment is harmful for the photocatalytic efficiency.• The coating stability is followed by HPLC and by surface analysis (XPS, contact angle).• Presence of the silica organic groups is necessary to increase the coating efficiency.

The authors also would like to thank Prof. T. Filleter from the NanoMechanics and Materials Laboratory, University of Toronto, for his review of the paper and his comments during the redaction process.; International audience; MoS2 is a well-known lubricant for vacuum application. However, the role of contamination in achieving low friction and long wear life in industrial applications remains unclear as the literature presents some contradictions. A former study performed in ultrahigh vacuum showed that in a sliding macro contact, the origin of low friction was primarily due to the formation of a 3rd body layer, its trapping and its ability to flow plastically inside the contact. The study showed a homogenisation of the chemical elemental composition of the material and the internal coating contaminants throughout the contact and the 3rd body. To study that homogenisation and to verify if a chemical rearrangement occurred at a molecular level under friction, Time-of-Flight Secondary Ion Mass Spectroscopy analyses are performed. Firstly, they show that the MoS2 coating made by Physical Vapour Deposition is not a "MoS2" but is a complex MoxSyOz structure. Secondly, they show that a chemical rearrangement of the material with the internal contaminants effectively occurs in ultrahigh vacuum and leads to the formation of a unique MoSxOy phase. Such a phase shows the beneficial role of reasonable contamination on the tribological behaviour.

International audience; Palladium(II)–thiol complexes were synthetized at the surface of patterned PDMS stamps and were transferred onto the surface of numerous substrates using microcontact printing (μCP) and submerged microcontact printing (SμCP). These complexes were used for the fabrication of micro- and nano-scale metal patterns following both top-down and bottom-up processes. For top-down processes, palladium(II)–thiol complexes were used as mask for wet chemical etching. For bottom-up processes, palladium(II)–thiol complexes were transferred onto silanized silicon wafers and plasma-treated polymers. Plasma post-treatments under reducing conditions led to palladium nanoparticles down to 10 nm in diameter. These nanoparticles were then used as catalysts for the electroless deposition of copper or nickel patterns. Patterns of 200 nm wide metal dots (high resolution) with a period of 400 nm (high density) can be obtained.