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The tin-free electroless metallization process developed in our laboratory consists in attaching the Pd(+ 2)-based catalyst on surfaces which were previously grafted with nitrogen-bearing groups. The so-functionalized surfaces lead to the formation of true covalent bonds between palladium and nitrogen-based species. In this work, the different steps of the process are studied, namely: (i) the grafting of nitrogen-bearing groups on an insulating surface by various processes already used in our laboratory, (ii) the seeding of the surface with Pd(+ 2) species, (iii) the reduction of Pd(+ 2) to Pd(0) by different routes (this step is needed due to the use of industrial plating baths which contain strong stabilizers that prevent or delay plating), (iv) the Ni metallization using low- and high-phosphorus plating baths. Phosphorus which originates from the plating bath reducer is partly incorporated in the Ni films and creates some stresses. Adhesion of the resulting films is evaluated by the Scotch® tape test. The main parameters responsible for adhesion and governing the characteristics of the Ni film/substrate interface are: the nature of the substrate, the Pd(+ 2) reduction route and the phosphorus content of the Ni plating bath. All these parameters influence the amount of stresses generated both at the metal/substrate interface and within the film.

Different polymer substrates were copper-plated by electroless deposition without using the Pd-based conventional catalyst to initiate the redox reaction. The principle of the process is based on the deposition of a copper(II) organic precursor film on the polymer surface to be metallized and on the reduction of the Cu(+ 2) ions. This reduction is obtained by different chemical, thermal, photonic or plasma techniques and its results were studied by XPS analysis. A polymer surface densely and homogeneously seeded with Cu(0) species allows to initiate the autocatalytic deposition of copper films. Their thickness was measured by X-ray fluorescence spectrometry and their adhesion evaluated by the Scotch® tape test.

The aim of this study was to compare the classifications of cross-country skiing gliding waxes based on their chemical composition and those based on the physical and physicochemical properties. Fifty commercial gliding waxes were analysed by gas chromatography to describe the alkanes, perfluorocarbons and perfluoroalkanes distributions and by ionic chromatography to define the fluorine elemental content. The physical and physicochemical properties of the studied waxes were measured by penetration tests at four different temperatures and by the wetting tests in static and dynamic modes. Principal Components Analysis was performed as a function of both the chemical composition descriptors and the physical and physicochemical characterisation results in order to identify the waxes typology. The classification based on the chemical composition showed that three groups could be defined: (1) long alkane waxes corresponding to the waxes recommended for the “cold” snow, (2) intermediate alkane waxes (“intermediate” snow) and (3) short alkane waxes (“warm” snow). The classification based on the physical and physicochemical properties pointed out that the waxes for the “cold” snow were the hardest waxes and the waxes for the “warm” snow, the softest ones. Moreover this classification suggested that the physicochemical properties were not linearly correlated with the fluorine additives content. The comparison between both typologies underlined that the waxes composed of long alkanes were the hardest ones while those of short alkanes were the softest ones as well as that the increase of waxes water-repellence was limited despite the increase in the fluorine based additives content. The main result of this study was that the strategy in wax development by the various manufacturers follows the same general trend in relation with the alkane composition but a fine analysis pointed out that each gliding wax manufacturer provides specific formulation in the case of the waxes containing fluorine based additives.

Electroless plating of nickel (or copper) was carried out on glass (or silicon) substrates that were previously surface modified by using plasma-polymerization and grafting processes, and then activated by immersion in a simple acidic PdCl2 solution. Three pretreatments based on the deposition of plasma-polymerized thin films (PACVD process) on O2 plasma-cleaned substrates were investigated. They include film deposition of (1) amorphous hydrogenated carbon (a-C:H) grown from CH4, whose surface is subsequently plasma-functionalized in NH3 or N2; (2) amorphous hydrogenated carbon nitride (a-CNx:H) grown from CH4/NH3 or CH4/N2 mixtures; and (3) amorphous hydrogenated carbon nitride grown from volatile organic precursors (allylamine, acetonitrile). In the three cases, X-ray photoelectron spectroscopy (XPS) results show that chemisorption of the catalyst occurs on the nitrogen-containing functionalities created by plasma polymerization and grafting and thus that the electroless deposition is possible. Differen...

Le procede electroless est un procede de metallisation (generalement Ni ou Cu) multi-etapes largement utilise dans de nombreux secteurs industriels. Dans le cadre du present travail, nous illustrons la complementarite des informations apportees par differentes techniques d'analyse de surface et la maniere dont l'utilisation de ces outils a conduit au developpement de nouvelles approches de la metallisation electroless des surfaces polymeres. Plus precisement, nous nous sommes interesses a la caracterisation par spectrometrie photoelectronique (XPS), spectrometrie de fluorescence X (XRFS) et spectrometrie d'emission X induite par excitation electronique de basse energie (LEEIXS) (i) de la surface de substrats de polyimide soumis successivement a un traitement plasma sous atmosphere NH 3 , une activation par immersion dans une solution acide de chlorure de palladium et a une reduction en solution d'hypophosphite des especes palladiees chimisorbees, et (ii) des films minces de Ni ou Cu deposes sur les substrats ainsi traites a partir de bains electroless commerciaux.

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International audience; Silver localization is obtained on polyimide Kapton HN (PI) in step by step processes combining surface treatments (chemical and plasma), microcontact printing (mu,CP) and electroless metal deposition. There processes are developed in order to obtain silver patterns onto flexible polymer surfaces at the micro and sub-micro scale. Patterns of silver dots or, at the opposite, of holes in silver layer, were obtained using the same PDMS polydimethylsiloxane (PDMS) stamp (positive/negative technology). Processes are based on the same first step, i.e. the PI surface functionalization with Ag(0) nanoparticles, catalyst to silver electroless metallization. p,CP step is based on a localized passivation with self-assembled monolayers (SAMs) of octadecanethiol (CH3(CH2)(17)SH; ODT). Those molecules are locally printed either on a continuous silver deposit or on the Ag(0) catalytic nanoparticles. Then, chemical etching and/or electroless deposition complete the localization process. Geometry and dimensions of silver patterns are discussed, highlighting the main parameters influencing high resolution (sub-micrometric scale) of these silver patterns.

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International audience; COOH-terminated self-assembled monolayers (SAMs) are widely used in biosensor technology to bind different amine-containing biomolecules. A covalent amide bond, however, can be achieved only if the carboxylic acids are activated. This activation process usually consists of forming an N-hydroxysuccinimidyl ester (NHS-ester) by consecutively reacting carboxylic acids with a carbodiimide and NHS. Though many papers report using this method,(1-8) the experimental conditions vary greatly between them and chemical characterization at this stage is often omitted. Evidence of an efficient activation is therefore rarely shown. Furthermore, recent publications(9-11) have highlighted the complexity of this process, with the possible formation of different byproducts. In this paper, we have conducted a study on NHS activation under different conditions with chemical characterization by polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). Our results indicate that the nature of the solvent and carbodiimide and the reactant concentrations play crucial roles in activation kinetics and efficiency.

International audience; The use of polymer materials in industry for product packaging is increasing. The presence of additives in the polymer matrix enables the modification or improvement of the properties and performance of the polymer, but these industries are concerned regarding the extractability of these additives. The quantification of these additives is particularly challenging because of the presence of these substances as contaminants in all the analytical equipment and the diversity of their physicochemical properties. In this context, a multi-residue analytical method was developed for the trace analysis of the twenty main additives (and their degradation products) authorized in plastic products such as pharmaceutical packaging (e.g., antioxidants, release agents, and light absorbers). This analytical method consisted of a solid phase extraction (SPE) followed by an analysis using ultra-high performance liquid chromatography coupled to a tandem mass spectrometer (UHPLC-MS/MS). A comparison of two ionization interfaces and the optimization of the extraction procedure were discussed. The influence of the quality of the solvent type (distilled versus not distilled) and the nature of the SPE cartridges (Polypropylene versus Teflon®) were demonstrated. The optimized method exhibited a quantification limit lower than 20 ng mL−1 and recoveries between 70 % and 120 % for all compounds. Finally, the method was validated according to the ICH directive and was subsequently applied to the extraction of polymers under different pH conditions and storage temperatures. To the best of our knowledge, this study presents the first methodology allowing the simultaneous quantification of 24 additives at low ng mL−1.

SSCI-VIDE+CARE+DAG:IBE:CGU; International audience; Photocatalytic porous coatings (micro-, meso- and macroporous) are obtained by the dispersion of TiO2 nanoparticles in sol–gel hybrid matrices. The sol–gel silica matrix is used as a binder stabilizing the nanoparticle dispersion and as a protective layer for the organic substrates. Organic groups are introduced into the matrix to induce the film flexibility and a part of them is used to create the final microstructure allowing remarkable improvement of the photocatalytic properties. The film structure and UV stability are fully characterized. The photocatalytic activity is evaluated through a test with formic acid. Flexible efficient photoactive composites are obtained showing important capabilities for depollution (water and air) and self-cleaning applications.

The potential of surface glycoengineering for biomaterials and biosensors originates from the importance of carbohydrate–protein interactions in biological systems. The strategy employed here utilises carbene generated by illumination of diazirine to achieve covalent bonding of carbohydrates. Here, we describe the synthesis of an aryl diazirine containing a disaccharide (lactose). Surface analysis techniques [X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS)] demonstrate its successful surface immobilisation on polystyrene (PS). Results are compared to those previously obtained with an aryl diazirine containing a monosaccharide (galactose). The biological activity of galactose- or lactose-modified PS samples is studied using rat hepatocytes, Allo A lectin and solid-phase semi-synthesis with α-2,6-sialyltransferase. Allo A shows some binding to galactose-modified PS but none to lactose-modified surfaces. Similar results are obtained with rat hepatocytes. In contrast, sialylation of lactose-modified PS is achieved but not with galactose-modified surfaces. The different responses indicate that the biological activity depends not only on the carbohydrate per se but also on the structure and length of the spacer.

Time-of-flight Secondary Ion Mass Spectrometry (ToF-SIMS) and x-ray photoelectron spectroscopy (XPS) are used to characterize a newly synthesized glycosylated photoactivatable reagent designed for surface glycoengineering. The immobilization on diamond surfaces of the glycoaryldiazirine reagent lactose aryl diazirine (5-carboxamidopentyl-N-[m-[3-(trifluoromethyl)diazirin-3-yl]phenyl-β-D-galactopyranosyl]-(1->4)-1-thio-β-D-glucopyranoside) is compared to a previously studied monoglycosylated photoactivatable reagent (MAD-Gal). The XPS atomic constituents and chemical shifts, as well as ToF-SIMS specific characteristic fragments and molecular peaks of the new photoimmobilized molecule are recorded. Spectral differences are identified in XPS C 1s spectra and in the high mass range of positive ion ToF-SIMS spectra for the surface immobilized disaccharide. The ToF-SIMS characteristic high-mass ions involve both cationization with Na+ and loss of the diazirine function. The results can be related to differences observed in biological assays with each of the surface immobilized saccharides. Copyright © 2001 John Wiley & Sons, Ltd.

In view of future generations of biosensors and advanced biomaterials, photochemistry in the near field using scanning near-field optical microscopy is investigated. The potential of direct near-field-induced photoactivation is demonstrated on standard photoresist. Photoimmobilization of maleimidoaryldiazirine on silicon substrates and bovine serum albumin on glass substrates is achieved, opening the way to a controlled biopatterning of surfaces with submicrometer feature size. The obtained patterns are characterized using atomic force microscopy, time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and near-field fluorescence microscopy.

Thin titanium hydride (TiHy) films, covered by ultrathin gold layers, have been compared with the corresponding titanium films after analysis using a combination of time-of-flight SIMS (ToF-SIMS), XPS and AES. The TiHy layers were prepared under UHV conditions by precisely controlled hydrogen sorption at 298 K on Ti film evaporated onto a glass substrate. Both Ti and TiHy films were then covered in situ by a nanoscale Au layer. Analyses were performed in separate systems after long-term exposure of the films to air. The thin gold layers covering the Ti and TiHy surfaces prevent any extensive air interaction with both films, allowing characterization of the bulk Ti and TiHy layers ex situ, even after a long-term application in air. The chemical nature of the TiHy layers has been analysed after sputtering of the Au top layer. The high-mass-resolution positive-ion ToF-SIMS spectra disclosed only one peak at mass 49 (49Ti+) for the Ti and two peaks at mass 49 (49Ti+ and 48TiH+) for the TiHy film, reflecting a difference in hydrogen concentration. Analysis of the features of the Ti Auger spectra during the sputter profile measurements allows the TiHy to be distinguished and characterized in the bulk region of the Au/TiHy layer. Besides TiHy, TiO and TiOH were detected by XPS to be the main chemical compounds in the interface region of the Au/TiHy film.

The surface chemical characterization of melamine–formaldehyde (MF) resins by x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) is examined in this study. Melamine–formaldehyde resins with different molar ratios of formaldehyde to melamine are synthesized and thermally cured. From XPS measurements, quantitative information is obtained and atomic chemical concentrations show the effect of the molar ratio for the freeze-dried resins. However, the thermally cured resins display a rather similar surface elemental composition. Moreover, because the binding energy values of the main N–C–N and N–C–O groups are too close, XPS does not help to identify changes in chemical structure after curing. The main ToF-SIMS negative and positive mass fragments of the MF resins are identified. Principal component analysis (PCA) is shown to be useful to determine and explain the main differences between all of the ToF-SIMS spectra. It allows us to distinguish the effect of the bulk chemical composition on the respective surface compositions of not only the uncured but also the cured MF resins. Moreover, extended interpretation leads to the identification of peaks characteristic of methylol groups and methylene ether bridges, but their absolute quantification is not straightforward. However, this result indicates that surface analysis helps to characterize the poorly defined chemical structure of MF resins. This is important for understanding the influence of surface chemistry on macroscopic surface properties such as chemical durability under exterior exposure. Copyright © 2000 John Wiley & Sons, Ltd.

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) has previously been successfully applied to characterize the covalent grafting of N-(m-(3-(trifluoromethyl) diazirine-3-yl)phenyl)-4-maleimido-butyramide (MAD), a reagent used for immobilization of biomolecules on solid surfaces, i.e., diamond substrates. In this study, the molecule was used to compare dose-related damage data obtained on two different ToF-SIMS systems, a PHI Trift and a PHI-7200 Reflectron, after shipping identically prepared samples to two independent laboratories. The ToF-SIMS spectrum in the negative ion mode exhibits characteristic signals over a large mass range, allowing to compare spectral differences in data acquired in the static SIMS regime with the two spectrometers to differences in experimental parameters, such as detector voltages. Variations in ion beam damage were not fully reproduced by both ToF-SIMS systems, indicating limitations in the comparison of ion beam damage data using two different sets of experimental parameters. This discrepancy could be related to different mass-dependent ion transmissions of the two spectrometers. The results suggest that a model developed in the literature for the interpretation of ion dose-induced polymer damage can be successfully applied to the case of organic molecules covalently attached to a diamond surface.

Time-of flight secondary ion mass spectrometry (ToF-SIMS) has been employed to characterize and evaluate the surface of a novel biochip prototype, consisting of an array of gold microelectrodes on ...

Surface modification by plasma treatment is an efficient way of improving metal adhesion to polymers. Here, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is used to characterize the surfaces of Teflon PFA and Teflon AF1600 films, following plasma treatments in H2, O2 and N2 gases. This work is complementary to our previous study using XPS, and is particularly directed toward the identification of incorporated hydrocarbons which could seriously affect metal adhesion. Plasma treatments strongly modify the surfaces of fluoropolymers, causing the ablation of a part of the fluorocarbon structure, with H2 being the most effective gas. The hydrocarbon content of such surfaces is not negligible, and a comparison with hydrocarbon levels on untreated surfaces suggests that a substantial fraction of this material was incorporated on plasma treatment; this is particularly so in the case of H2 plasma treatment. Due to expected strong matrix effects caused by significant changes in surface chemistry and structure following the various plasma treatments, the use of SIMS absolute intensity values is discussed in terms of data treatment artifacts. Moreover, due to the differences in secondary ion yields between characteristic hydrocarbon and fluorocarbon SIMS peaks, the use of peaks normalized to the total intensity is also impractical. Here, positive mode absolute intensities and negative mode peak intensity values, when normalized to Itot - I(H−) - I(F−), give valuable information, as in the comparison of hydrocarbon and N incorporations.

Recent time-of-flight secondary ion mass spectrometry studies using primary ion cluster sources such as Aun+, SF5+, Bin+ or C60+ have shown the great advantages in terms of secondary ion yield enhancement and ion formation efficiency of polyatomic ion sources as compared to monoatomic ion sources like the commonly used Ga+. In this work, the effective gains provided by such a source in the static ToF-SIMS analysis of microelectronics devices were investigated. Firstly, the influence of the number of atoms in the primary cluster ion on secondary ion formation was studied for physically adsorbed di-isononyl phthalate (DNP) (plasticizer) and perfluoropolyether (PFPE). A drastic increase in secondary ion formation efficiency and a much lower detection limit were observed when using a polyatomic primary ion. Moreover, the yield of the higher mass species was much enhanced indicating a lower degree of fragmentation that can be explained by the fact that the primary ion energy is spread out more widely, or that there is a lower energy per incoming ion. Secondly, the influence of the number of Bi atoms in the Bin primary ion on the information depth was studied using reference thermally grown silicon oxide samples. The information depth provided by a Bin cluster was shown to be lowered when the number of atoms in the aggregate was increased.

We report a new approach for immunoassays based on magnetite nanoparticles for Escherichia coli (E. coli) detection using conductometric measurements. Biotinylated antibodies, anti-E. coli, were immobilized on streptavidin modified magnetite nanoparticles by biotin–streptavidin interaction. A layer of functionalized nanoparticles were directly immobilized on the conductometric electrode using glutaraldehyde cross-linking.The specific test with E. coli cells and the non specific test using Staphylococcus epidermidis (S. epidermidis) were investigated by conductometric measurements. Results show a good response as a function of antigen additions. The detection of 1 CFU/ml of E. coli induces a conductivity variation of 35 μS. The negative test shows good selectivity using the conductometric immunosensor. Conductometric measurements allow to detect 500 CFU/l. Keywords: E. coli, Antigen–antibody interaction, Conductometric immunobiosensor, Magnetite nanoparticles, Atomic force microscopy

Teflon AF, an amorphous copolymer of polytetrafluoroethylene (PTFE) with 2,2-bis(triflouromethyl)-4,5-difluoro-1, 3-dioxole, has been receiving widespread attention in the opto-electronics industries and elsewhere for its superior optical and dielectric properties. The objective of the present study was to investigate surface parameters that may be required for the application of thin films of Teflon AF in the fields of biomaterials and bioelectronics. Using standard microelectronics procedures, micro-patterned thin films of Teflon-AF were fabricated, and their surface properties monitored and optimized with the aid of highly surface sensitive spectrometric techniques. Finally, their capability to inhibit or bio-pattern cell adhesion was tested with various neural cell lines.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and x-ray photoelectron spectroscopy (XPS) are used to characterize the grafting of the reagent N-(m-(3-(trifluoromethyl)diazirine-3-yl)phenyl)-4-maleimido-butyramide (MAD) to various substrates: silicon, silicon nitride and diamond. MAD carries a maleimide function for thermochemical modification of thiolated molecules and a diazirine function that is lost during light activation (350 nm light). Photoactivation leads to carbene-mediated grafting to solid supports. X-ray photoelectron spectroscopy atomic constituents and chemical shifts, as well as ToF-SIMS molecular peaks and characteristic fragments of the photoimmobilized molecule, are identified. Extended interpretation of surface analysis data suggests that diamond is the substrate with the highest MAD grafting efficiency and that the formation of C-O bonds upon diazirine photoactivation is involved. The difference in grafting extent for the three substrates leads to the conclusion that other reaction sites could be involved but they are not identified. © 1998 John Wiley & Sons, Ltd.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and x-ray photoelectron spectroscopy (XPS) are used to characterize a newly synthesized glycosylated photoactivatable reagent designed for surface glycoengineering. The glycoaryldiazirine reagent MAD-Gal (N-[m-(3-(trifluoromethyl)diazirine-3-yl)phenyl]-4-(-3-thio(-1-D- galactopyrannosyl)-maleimidyl)butyramide) is immobilized with 350 nm light on diamond surfaces. The XPS atomic constituents and chemical shifts, as well as ToF-SIMS-specific characteristic fragments of the photoimmobilized molecule, are identified. The grafting on oxygen-containing sites previously observed for N-(m-(3-(trifluoromethyl)diazirine-3-yl)phenyl)-4-maleimido-butyramide (MAD) is confirmed. The difference in grafting efficiency for fresh and aged substrates indicates that other still unidentified reaction sites could be involved. The ToF-SIMS imaging is used to exhibit the ability to pattern the surface with the glycosylated aryldiazirine. © 1998 John Wiley & Sons, Ltd.

Instituto de Fsica de S¼o Carlos, Universidade de S¼o Paulo, Av. Trabalhador S¼o-carlense 400, S¼o Carlos, SP, postcode 369,13560-970, Brazil*e-mail: gdebora@ifsc.usp.brReceived: October 17, 2012Accepted: December 4, 2012Published online: February 22, 2013AbstractThe process for obtaining polypyrrole-2-carboxylic acid (PPY-2-COOH) films in acetonitrile was investigated usingcyclic voltammetry, electrochemical quartz crystal microgravimetry (EQCM), and infrared spectroscopy (FTIR).Different potential ranges were applied during cyclic voltammetry experiments with the aim of obtaining films with-out and with the presence of controlled amounts of water added in acetonitrile. The FTIR spectra of the films haveevidenced that cations and anions from the electrolyte solution were incorporated into the PPY-2-COOH structure,with a preferential adsorption of cations. After chemically immobilizing polyphenoloxidase (tyrosinase, PPO), PPY-2-COOH/PPO films were build for amperometric detection of catechol, establishing a linear limit of concentrationsranging from 5.010

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is used to monitor in a semi-quantitative way the chemical modifications produced at low-density polyethylene (LDPE) film surfaces by SF6 and SF6-CF4 plasma treatments. The influence of the plasma treatment time (SF6 plasma) and the gas composition (SF6-CF4 plasma) have been investigated, The ToF-SIMS results are compared with plasma diagnostics (mass spectrometry and optical emission spectroscopy) and with some earlier XPS characterization. The ToF-SIMS study of SF6 plasma-treated LDPE films as a function of the treatment time shows two different structural developments, Beside the expected formation of CxFy structures due to the grafting of F atoms, ToF-SIMS detects the presence of SFx species at the surface. Their high sensitivity to ablation, due to the plasma ions, was related to two possible interactions of plasma species with the LDPE surface: an adsorption of SFx+/- ions or a dissociative chemisorption of SFx neutral species. In the latter case, the low binding energy of the S-C bond can explain the high sensitivity to ablation. In the case of SF6-CF4 plasma treatment, the incorporation of fluorine, as seen by ToF-SIMS, is a function of the gas composition. Two maxims are observed when the second gas (either SF6 or CF4) is introduced at low concentration (similar to 10%). These maxims are confirmed by XPS and actinometric results and are explained with respect to the reciprocal influence of both gases in the plasma discharge.

International audience; Oligonucleotide solid-phase synthesis is now possible on nano-sized particles, thanks to the use of controlled pore glass-nanoparticle assemblies. We succeeded in anchoring silica nanoparticles (NPs) inside the pores of micrometric glass via a reversible covalent binding. The pore diameter must be at least six times the diameter of the nanoparticle in order to maintain efficient synthesis of oligonucleotides in the synthesizer. We demonstrated that the pores protect NP anchoring during DNA synthesis without decreasing the coupling rate of the phosphoramidite synthons. This bottom-up strategy for NP functionalization with DNA results in unprecedented DNA loading efficiency. We also confirmed that the DNA synthesized on the nanoparticle surface was accessible for hybridization with its complementary DNA strand.

Polyethylene has been treated in a CF4 plasma using two configurations for the electrodes: parallel-plate electrodes at 13.56 MHz, and a nonsymmetrical configuration of electrodes at 70 kHz. The chemical species involved in the plasmas and the subsequent surface modifications were characterized. Comparison of the emissions in the range 200-450 nm was made with optical emission spectroscopy. The excited radicals' CF2 bands and the CF+ broad continuum were detected and a comparison of their relative intensities indicated a more energetic aspect to the low-frequency discharge. This was confirmed by comparing the ratio of N2+/N2 in the two cases. Analysis of the surface properties by means of X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectrometry (SSIMS), and contact angle measurements showed rapid fluorination of the surface (t = 0.1 s) for the nonsymmetrical electrodes. Longer treatment times (up to 15 s) led to more fluorinated surfaces, thereby decreasing the wettability of the treated substrates; fluorine incorporation was, however, more significant at equivalent treatment times in the diode reactor. SSIMS analysis indicated the formation of more complex fluorine compounds with an increase in the treatment time with no notable modification other than replacement of H by F. Further increases in the treatment time for low-frequency treated samples in the nonsymmetrical configuration of electrodes caused an increase in the surface roughness, as observed by SEM (scanning electron microscopy) analysis. RBS (Rutherford backscattering spectroscopy) measurements showed that beyond 0.1 s, which corresponds to the time required for rapid fluorination, fluorine diffuses through the polymeric matrix and its concentration is enhanced with increasing treatment time.

International audience

National audience; La lithographie douce et plus particulièrement la technique de microtamponnage sont utilisées ici dans le but de fabriquer des microélectrodes pouvant servir à l'élaboration de microcapteurs. Deux voies originales sont décrites, l'une basée sur le pelage localisé d'une couche métallique à l'aide d'un adhésif et l'autre sur la croissance localisée d'une couche métallique electroless. Il est montré que ces deux procédés permettent la reproduction de motifs à l'échelle micrométrique.

This work presents a new sensor for ammonium determination based on interdigitated conductometric thin-film planar electrodes. It was fabricated by including nonactin in a plasticised poly(vinyl chloride) membrane deposited on the sensitive area of the transducer. The effects of pH, buffer concentration, the interferences of Na+, K+ and Ca2+ ions, the effect of ionic strength and of temperature were investigated. The linear working range and sensitivity of the biosensor were also determined. The sensitivity of the ammonium detection was around 6.2 S M-1 [image omitted] and the detection limit was 2 10-5 M. The biosensor exhibits the advantages of a simple fabrication procedure, good sensor-to-sensor reproducibility, wide dynamic range and good storage stability (12 weeks).

International audience; The chemical reactivity of the ligand initially coordinated on the TiO2 precursor plays a decisive role in the morphology of TiO2:poly(N-vinylcarbazole) (PVK) thin film elaborated by in situ generation of the inorganic phase in the polymer matrix. The final aim of this study is to prepare a new nanocomposite TiO2:poly(N-vinylcarbazole) (PVK) thin film from hydrolysis-condensation of titanium alkoxide in polymer thin film. In this context, we synthesized a new TiO2 precursor, the tetrakis (9H-carbazole-9-yl-ethyl-oxy) [Ti(OeCarb)4], bearing ligands close to the repetitive unit structure of the PVK to improve the interaction between both materials. In this study, the synthesis and reactivity to hydrolysis of Ti(OeCarb)4 is presented. Ti(OeCarb)4 was elaborated from alcoholysis reaction between titanium isopropoxide [Ti(iOPr)4] and 9H-carbazole-9-ethanol (ECOH) and identified by 1H and 13C NMR spectroscopy. The reactivity to hydrolysis-oxolation of Ti(OeCarb)4 was evaluated first in aqueous media by in situ 1H NMR spectroscopy analysis. Moreover, reactivity of Ti(OeCarb)4 to surrounding humidity was evaluated in thin film by X-ray photoelectron spectroscopy (XPS). Results show that steric hindrance of 9H-carbazole-9-yl-ethyl-oxide ligands do not influence the hydrolysis-condensation process in aqueous media in our experimental conditions when compared to [Ti(iOPr)4] but decrease the reactivity when the precursor is simply exposed to air humidity.

Polyethylene Terephthalate 12-mu-m thick films (Mylar(R)) have been subjected to an industrial gaseous fluorination treatment. The chemical surface modifications of the treated films have been studied with the aid of various surface sensitive techniques (ISS, SSIMS and XPS); thanks to the complementarity of these techniques, the chemical reaction scheme at the surface is emphasized. The ISS technique provides the elemental chemical composition of the first topmost monolayer. In the case of polymers, it is thought that the low carbon sensitivity of ISS is due to the shielding of the carbon atoms by the hydrogen atoms. ISS spectra obtained on fluorinated PET samples show that the fluorination treatment results in the incorporation of fluorine with a slight change of the O/C ratio: this has been interpreted by the substitution of hydrogen atoms from the PET by fluorine which has already been observed on other polymers subjected to the same treatment. Both XPS and SSIMS analyses confirm these results. First, the SSIMS spectra obtained on the fluorinated samples are totally different from those obtained on the untreated PET samples: these spectra exhibit new peaks characteristic of fluorine containing molecular ions similar to those observed from fluorinated polymers such as PVDF or PTFE. Since the secondary ions formation involves ruptures of the polymer chains and some recombination reactions, it is difficult to decide from SSIMS on the exact sites on the PET chains where the hydrogen substitution by fluorine takes place. This was made possible with the help of XPS: the shape of the C1s peak after fluorination of the PET shows that the formation of new CF(x) species (x less-than-or-equal-to 2) occurs on the electron rich benzenic rings of PET rather than on the aliphatic parts of the PET chains. Finally, RBS has been used in order to estimate the depth at which the fluorination treatment has proceeded: this has been estimated to a few tenths of micrometer.

International audience; The paper describes the development of a conductometric biosensor for detecting trimethylamine (TMA) which is a good parameter for estimating fish freshness. The biosensor consists of two parts: a microconductometric transducer and a structured enzymatic membrane using a flavin-containing monooxygenase 3 (FMO3) which is known for its sensitivity and selectivity for TMA. The process parameters for the fabrication of the biosniffer and various experimental variables such as pH, time of exposure to glutaraldehyde vapour were investigated with regard to their influence on sensitivity and limit of detection. A low detection limit of 2 mu g/mL (ppm) and a linear range up to 40 mu g/mL (ppm) were obtained. 90% response was reached in less than 10 min. (c) 2007 Elsevier B.V. All rights reserved.

A conductometric biosensor for nitrite detection was developed using cytochrome c nitrite reductase (ccNiR) extracted from Desulfovibrio desulfuricans ATCC 27774 cells immobilized on a planar interdigitated electrode by cross-linking with saturated glutaraldehyde (GA) vapour in the presence of bovine serum albumin, methyl viologen (MV), Nafion, and glycerol. The configuration parameters for this biosensor, including the enzyme concentration, ccNiR/BSA ratio, MV concentration, and Nafion concentration, were optimized. Various experimental parameters, such as sodium dithionite added, working buffer solution, and temperature, were investigated with regard to their effect on the conductance response of the biosensor to nitrite. Under the optimum conditions at room temperature (about 25 degrees C), the conductometric biosensor showed a fast response to nitrite (about 10s) with a linear range of 0.2-120 microM, a sensitivity of 0.194 microS/microM [NO(2)(-)], and a detection limit of 0.05 microM. The biosensor also showed satisfactory reproducibility (relative standard deviation of 6%, n=5). The apparent Michaelis-Menten constant (K(M,app)) was 338 microM. When stored in potassium phosphate buffer (100mM, pH 7.6) at 4 degrees C, the biosensor showed good stability over 1 month. No obvious interference from other ionic species familiar in natural waters was detected. The application experiments show that the biosensor is suitable for use in real water samples.

International audience; An original approach based on X-ray photoelectron spectroscopy (XPS) is proposed to study the influence of the surrounding humidity on the hydrolysis-condensation reactions of five titanium alkoxides in thin films. More precisely, the influence of the nature of the ligands (propoxide, butoxide, isopropoxide, phenoxide, and 9H-carbazole-9-yl-ethyl-oxy) on the reaction rate was evidenced. The reaction advancement was evaluated by comparing XPS chemical compositions to theoretical compositions calculated for all the possible rates. XPS chemical environment information allowed validating the reliability of this approach through the evaluation of the condensation state. In both approaches, the influence of the steric hindrance on the reactivity of titanium alkoxides was highlighted to be similar to what has been previously observed in solution. Theses results corroborate the validity of our XPS approach to determine titanium alkoxide hydrolysis-condensation reactions in the specific application of thin films.

A conductometric biosensor for phosphate detection was developed using maltose phosphorylase (MP) from recombinant Escherichia coli immobilized on a planar interdigitated electrode by cross-linking with saturated glutaraldehyde (GA) vapour in the presence of bovine serum albumin (BSA). The process parameters for the fabrication of the mono-enzymatic sensor and various experimental variables such as the enzyme loading, time of immobilization in saturated GA vapour, working buffer solution and temperature were investigated with regard to their influence on sensitivity, detection limit, dynamic range, operational and storage stability. The biosensor can work well at the temperature between 20 degrees C and 50 degrees C, and reach 90% of steady-state conductance in about 10s. The sensor has two linear ranges, one is from 1.0 microM to 20 microM phosphate with a detection limit of 1.0 microM, and the other is between 20 microM and 400 microM phosphate. When stored in citrate buffer (0.1M, pH 6.0) at 4 degrees C, the biosensor showed good stability over two months. No obvious interference from other anionic species like SO(4)(2-), Cl(-), NO(3)(-), NO(2)(-) and HCO(3)(-) was detected. The biosensor is suitable for use in real water samples.

International audience; To study cell attachment to biomaterials, several proteins such as fibronectin, collagen IV, heparin, immunoglobulin G, and albumin have been deposited onto polystyrene adsorbed on a self-assembled monolayer (silane or thiol) on glass or gold, respectively. The different steps of this multilayer assembly have been characterized by electrochemical impedance spectroscopy (EIS). These data are compared to those of adhesion rate, viability percentage, and cytoskeleton labeling for a better understanding of the cell adhesion process to each protein. All the proteins are endothelial cell adhering biomolecules but not with the same features. A linear relationship has been established between adhesion rate and resistance of the endothelial cell/protein interface for all negatively charged proteins.

Oleic acid-coated magnetite has been encapsulated in biocompatible magnetic nanoparticles (MNP) by a simple emulsion evaporation method. The different parameters influencing the particles size were studied. Between these parameters, the stirring speed and the polymer concentration were found to influence positively or negatively, respectively, the MNP size which varied between 320 and 1500nm. The magnetite encapsulation efficacy was about than 90% yielding a high magnetite loading of up to 30% (w/w). X-ray diffraction showed that magnetite crystalline pattern was not modified after emulsification and solvent evaporation. The X-ray photoelectron spectroscopy (XPS) results indicated the presence of less than 0.1% of iron atoms at the nanoparticles surface. Vibration simple magnetometer (VSM) showed a superparamagnetic behaviour of the MNP and a saturation magnetization increasing with the increased magnetite amount used in formulation. Moreover, T(1) and T(2) relaxivities of MNP (4.7T, 20 degrees C) were 1.7+/-0.1 and 228.3+/-13.1s(-1)mM(-1), respectively, rendering them in the same category of known negative contrast agents which shorten the T(2) relaxation time. Therefore, by using an appropriate anticancer drug in their formulation, these magnetic nanoparticles can present a promising mean for simultaneous tumor imaging, drug delivery and real time monitoring of therapeutic effect.

Lanthanum-manganese based perovskites were prepared, both at atmospheric pressure (MW) and at higher pressure (MWHyd), under microwaves irradiation. Structural and physico-chemical properties of the catalysts were investigated using X ray diffraction, X-ray photoelectron spectroscopy (XPS), BET-sorption, and temperature programmed reduction-, or desorption coupled with mass spectrometry, (TPR-MS or TPD-MS). While MW and MWHyd 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 procedure. The influence of the nature of oxygen species, their amount and their mobility, evidenced by temperature programmed experiments, on the catalytic properties in catalytic combustion of methane in the presence and in the absence H 2 S has been studied.

The application of synthetic polymers in the growing field of materials for medical applications is illustrated by examples from recent work at the Materials Institute of the Swiss Federal Institute of Technology in Lausanne. The review highlights the need for functionalization and chemical control of material surfaces at a molecular/functional level. After a brief introduction into the surface chemical analysis tools, i.e., X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) combined with contact angle measurements, phosphorylcholine biomimicking polymers as well as immobilization of carbohydrates on polystyrene are presented.

Biological systems make considerable use of specific molecular interactions. Many biomolecules involved in biorecognition are glycosylated, the carbohydrate moiety playing an essential role. Controlled surface glycoengineering is thus of crucial importance in biosensing, cell guidance, and biomedical applications. This study describes the synthesis of an aryldiazirine-derivatized galactose and the functionalization of surfaces by carbohydrates using photochemical immobilization techniques. A photoactivatable glycosylated reagent was synthesized by addition of thiogalactopyranose to the maleimide group of N-[m-[3-(trifluoromethyl)diazirin-3-yl]phenyl]-4-maleimidobutyr amide (MAD) to give N-[m-[3-(trifluoromethyl)diazirin-3-yl]phenyl]-4-[3-thio (1-D-galactopyranosyl)succinimidyl]butyramide (MAD-Gal). The structure of the newly synthesized molecule was confirmed by UV spectroscopy, photoactivation, 1H NMR, and 13C NMR. MAD-Gal was immobilized on thin diamond films by photoactivation of the diazirine function (350 nm). Surface modification was investigated by XPS (X-ray photoelectron spectroscopy) and ToF-SIMS (time-of-flight secondary ion mass spectrometry). Imaging ToF-SIMS was applied to detect glycopatterns generated by mask-assisted lithography.

Static SIMS (SSIMS) has been used as an analytical tool for the study of the physicochemical changes following the surface treatments of polyolefin samples. First, the influence of the treatment duration has been investigated for nitrogen plasma and flame treated polypropylene (PP). Then, in order to confirm the interpretation of these SSIMS results, the influence of the plasma atmosphere and of the treatment duration on the surface modifications has been studied for hexatriacontane (C36H74), a model compound of linear saturated hydrocarbons. SSIMS results are discussed in light of the other complementary physicochemical characterizations presented previously, namely, surface energy measurements and XPS analyses.

National audience; Les matières plastiques sont utilisées dans de nombreux domaines d'applications, et en particulier dans celui du conditionnement. Or, l'inertie d'un conditionnement vis à vis de son contenu est rarement totale. La migration des additifs correspond à l'interaction la plus préoccupante pour la santé du consommateur car elle peut affecter la qualité du produit et/ou le rendre toxique. Dans ce contexte, répondre à la problématique du suivi de la migration des additifs de manière optimale implique de mettre au oeuvre des méthodes analytiques fiables avec un haut degré de sélectivité, spécificité et sensibilité. Pour cela, il est nécessaire (i) de développer des techniques de préparation d'échantillon qui permettent de concentrer la teneur en additifs contenus dans le milieu en contact avec le conditionnement, et (ii) d'employer des techniques d'analyses adaptées permettant d'identifier et/ou quantifier à la fois les additifs présents dans le contenu et de pouvoir les imputer au contenant.

Commercially pure titanium (cp Ti) is widely used in dental implantology. However, it is only passively integrated in bone and the resulting fixation in the bone, which is necessary for the function, is mainly mechanical in its nature. With the objective of increasing the chemical interaction between the implant and bone tissue, several phosphonic acids were synthesized and grafted onto titanium disks. The bare polished Ti disks (Ti P) and the grafting of three phosphonic acids (methylenediphosphonic acid (MDP), propane-1,1,3,3-tetraphosphonic acid (PTP), and ethane-1,1,2-triphosphonic acid (ETP)) on these disks were characterized with X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). These surface analytical techniques provided strong indications of the formation of a chemical link between the Ti implant and the phosphonic acid molecule. The bioactivity of the modified Ti disks was evaluated by incubating these disks in a physiological solution (Hank's ...

International audience

During the last decade, organic electronics have developed rapidly. However, the production of organic electronic devices is still impeded because of various technological barriers. Such systems have specific analytical needs and time-of-flight secondary ion mass spectrometry (ToF-SIMS) is per se highly relevant, particularly when considering the use of a new type of ion source based on argon clusters (Arn +). The main objective of this work was therefore to understand the ion-matter interactions of such a cluster beam with the organic materials used in organic electronics. A fundamental study was carried out by comparing sputtering with three different ion beams (Cs+, C60 ++, Arn +) on organic structured samples (such as PS-b-PMMA block copolymers) and it transpired that although cluster size and energy has little effect on the observable damage to the sample, larger argon clusters induce more roughness during ToFSIMS depth profiling. This was confirmed by AFM (Atomic Force Microscopy) and XPS (Xray Photoelectron Spectroscopy) and a geometric model. Next, different devices in organic electronics were characterized by ToF-SIMS. The study of self-assembling PS-b-PMMA block copolymers made possible to evaluate the influence of the annealing duration and of the thickness of the layer. Furthermore, a protocol was developed to analyse stacks of inorganic/organic layers, in particular those contained in OLED devices. It was then possible to characterize the stacks of a complete organic light-emitting device whilst maintaining molecular signal and a high depth resolution of 2 nm. In parallel we identified the chemical degradation of an organic material in the stack and evaluated the efficiency of barrier layers designed to protect it. More precisely, specific signatures to the hydrolysis reaction of the layer as well as increase in moisture level after encapsulation were identified; L'électronique organique a connu durant la dernière décennie un essor considérable. La production de dispositifs à base de matériaux organiques reste néanmoins freinée par différents verrous technologiques. La caractérisation de ce type de systèmes conduit à des besoins analytiques spécifiques et la spectrométrie de masse des ions secondaires à temps de vol (Timeof-Flight Secondary Ion Mass Spectrometry – ToF SIMS) est a priori très pertinente notamment grâce à l'utilisation d'un nouveau type de faisceau d'ions à base d'agrégats d'argon (Arn +). L'objectif principal de ce travail a donc été de comprendre l'interaction ions-matière d'un tel faisceau avec les matériaux organiques utilisés en électronique organique. Une étude fondamentale a d'abord été réalisée en comparant différents faisceaux d'ions de décapage (Cs+, C60 ++, Arn +) sur des échantillons organiques structurés (tels que les copolymères à blocs PS-b-PMMA) et il est apparu que, bien que la taille des agrégats et leur énergie ont peu d'effet sur l'endommagement observable sur les échantillons, les agrégats d'argon de grande taille induisent de la rugosité lors du profil en profondeur ToF SIMS, sans modification chimique, ce qui a été confirmé par des analyses complémentaires – AFM (Atomic Force Microscopy) et XPS (X-ray Photoelectron Spectroscopy) – et une modélisation géométrique. Ensuite, différents dispositifs du domaine de l'électronique organique ont été caractérisés. Ainsi, l'étude de l'auto structuration des copolymères à blocs PS-b-PMMA a permis d'évaluer l'influence du temps de recuit et de l'épaisseur de la couche. Par ailleurs, un protocole a été développé pour l'analyse d'empilements de couches inorganiques/organiques, notamment ceux des OLED. Il a ainsi été possible de caractériser par profil en profondeur ToF-SIMS les différents empilements d'un dispositif de l'électronique organique en conservant la détection d'un signal moléculaire et une haute résolution en profondeur de 2 nm. Parallèlement, nous avons identifié la dégradation chimique d'un matériau organique du multicouche constitutif de l'empilement et évalué la protection de celui-ci via des couches barrières. Plus précisément, les signatures de la réaction d'hydrolyse de la couche ont été identifiées ainsi que la teneur en humidité après encapsulation