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A general approach to side-chain allyl-functionalization of three different polyelectrolytes (PEs), namely poly(allylamine hydrochloride) (PAH·HCl), branched polyethyleneimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS), is reported for the first time. This functionalization does not affect the electrolytic properties of the newly functionalized PEs (named PEs-ene), as confirmed by the effective formation of PE-ene multilayer (PEM) films. The stepwise construction of these films is monitored using different techniques, including QCM, SEM, XPS, and WCA measurements. The incorporation of allyl functional groups into the PE side-chains allows for the stabilization of the resulting PEM films via thiol–ene UV photo-crosslinking in the presence of a water-soluble dithiol crosslinker. To overcome the problem of film delamination, the covalent crosslinking occurs not only between different layers of PEM films but also with the substrates preliminarily functionalized with allyl functional groups either via sulfur–gold chemistry or via chemical reduction of aryldiazonium salts using two newly synthesized anilinium derivatives. The stability of the resulting crosslinked PEM films in a strongly alkaline solution (pH = 14) is validated on gold substrates under QCM conditions (from 30 min to 3 h), while XPS and WCA measurements are used for evidencing such a stability under strongly acidic conditions (pH = 1) or at high salt concentration (saturated NaCl solution) on a modified anion-exchange membrane during a longer study time, i.e. 10 days. Finally, this stability study also gives evidence for a greater crosslinking efficiency of PEG-diSH, namely a macromolecular crosslinker, over dithiothreitol (DTT), a small molecule. The versatility and effectiveness of the approach presented here are expected to find widespread interest in different fields of emerging applications.

Different synthesis protocols have been developed to control TiO2 anatase nanoparticle packing. The diameter of TiO2 packing aggregate varies from 13 nm to a few 100 nm. Efficiency of dye-sensitized solar cells (DSSC) fabricated with the obtained TiO2 packing aggregate films was reported to depend on the size of the packing aggregate. It increases with the increase of the aggregate size (number of TiO2 nanoparticles) to a maximum of 4.3% and then it decreases. This effect was discussed in terms of a balance between the incident light scatterings, adsorbing amount of dye molecules, cracks free and the efficiency of electron transfer (reduction of recombination process).

A new electrochemical synthetic method for the transition metal-catalyzed homocoupling of 2-halopyridinic compounds into symmetrical 2,2’-bipyridines is described. Experiments were carried out in a cavity cell under various reaction conditions, using a nickel complex as catalyst, and controlled-potential or constant-current electrolyses. A graphite powder/carbon nanotube 9:1 ratio mixture proved to constitute the optimal cathode material. Excellent homocoupling product yields were observed using aqueous KCl solution as anolyte. The cathode material proved to be recyclable with possible reuse three times without notable loss of activity.

The effects of iron nanoparticles on bryophytes (Physcomitrella patens) were studied following foliar exposure. We used iron nanoparticles (Fe–NP) representative of industrial emissions from the metallurgical industries. After a characterization of iron nanoparticles and the validation of nanoparticle internalization in cells, the effects (cytotoxicity, oxidative stress, lipid peroxidation of membrane) of iron nanoparticles were determined through the axenic culturing of Physcomitrella patens exposed at five different concentrations (5 ng, 50 ng, 500 ng, 5 µg and 50 µg per plant). Following exposure, the plant health, measured as ATP concentrations, was not impacted. Moreover, we studied oxidative stress in three ways: through the measure of reactive oxygen species (ROS) production, through malondialdehyde (MDA) production and also through glutathione regulation. At concentrations tested over a short period, the level of ROS, MDA and glutathione were not significantly disturbed.

The aim of this study was to highlight the properties of novel phosphorus-containing β-cyclodextrin polymers (CDP) and mainly their dual complexing abilities toward hydrophobic guests and (bio)minerals. Affinity of CDP toward divalent metal cations, calcium, magnesium and zinc, has been investigated by isothermal titration microcalorimetry (ITC). The complexation constants K were around 1.1–6.2 × 104 L mol−1 and were in the order Ca2+ < Mg2+ < Zn2+. The K regular increase with the CDP molecular weights could be attributed to a cooperative binding of the cations by the monophosphate groups carried by the CDPs. Regarding their CD and phosphorus functionalities, the dual complexing abilities toward amphiphilic guests and divalent cations can occur independently as evidenced from ITC experiments performed in presence of both species. Finally, strong interactions between CDPs and hydroxyapatite have been highlighted by X-ray photoelectron spectrometry with adsorbed amount in the range of 2 mg/m2. CDPs are thus promising materials endowed with dual functionalities which could serve in biomaterials to simultaneously entrap bioactive molecules and capture (bio)minerals.

Thermal degradation of blue phosphor BAM:Eu 2 + under air is investigated using XPS, XRD, EPR and photoluminescence (PL) in order to analyze the loss of intensity in terms of modifications of the dopant distribution in the crystal cell and between crystal bulk and surface. This study reveals the key role played by oxidation-driven 2D diffusion of europium and barium, that results in important concentration gradients and makes degradation strongly dependent on both microstructure and cooling speed. Also based upon cation mobility, a possible regeneration effect is evidenced at moderate temperature. Flux treatments, known to increase the intensity of photoluminescence, also appear to reduce thermal degradation by lowering specific surface; they also enhance the regeneration process by forming extended single-crystal domains conducive to cation diffusion.

The influence of copper derived TiO

The adsorption of S-histidine on gold and copper well-defined surfaces has been characterised by reflection absorption infrared spectroscopy (RAIRS), a surface technique that gives chemical as well as orientational information. Analyses were carried out in a UHV chamber. The RAIRS data are in agreement with the following conclusions. Under low pressure of histidine, 10−8 mbar, histidine molecules form an adsorbed molecular layer on Au (1 1 1) and Cu (1 1 0) surfaces. On gold, histidine mainly adsorbs through the depronated carboxylate group in a quasi-upright geometry that maintains the imidazole ring far from the surface. On copper, the histidine NH2 and COO− groups are involved in the interaction with the surface, with the cycle closer to the surface.

Adsorption of (S)-histidine on Cu(110), and Cu(110) modified by adsorbed oxygen, has been studied by reflection absorption infrared spectroscopy (RAIRS). The molecular form and the orientation of the histidine molecule were deduced from experimental RAIRS data; moreover, vibrational spectra were simulated with a molecular mechanics force field (MMFF) calculation to address vibrational modes and the geometry of the adsorbate. The molecule preferentially binds to the surface in its HHis- molecular form. On the metallic Cu(110) surface, the adsorption occurs via the carboxylate group (COO-), with the two oxygen atoms equidistant from the surface, and via the dehydrogenated nitrogen of the imidazole group; the latter adopts an upright position with respect to the copper surface. The amino group (NH2) is likely to be maintained close to the surface, thus facilitating the interaction with the metal. Preadsorption of oxygen (θ ≈ 0.3) on the copper surface induces minor changes in the molecular orientation: the ...

Surface composition and electronic structure of AlPdMn quasicrystalline alloy have been studied for temperature ranging from 300 K to 873 K. The quasicrystalline nature of the in-situ prepared surface was identified by the unusual behaviour of the core level photoemission peaks of Mn as already demonstrated by Thiel et al. Quantitative estimation of surface concentration by measuring the peak on background ratio in Auger electron spectroscopy (AES) do not allow to concluded to surface segregation of one element whatever the substrate temperature. Auger transitions implying valence band electrons in the Auger relaxation reveal interesting shapes and energies modifications that can be correlated with the typical electronic structure of this alloy. The appearance of strong satellite structure in the Auger and photoemission spectrum can be attributed to bulk plasmon of the quasicrystalline phase.

In situ interactions of trivinylethoxysilane (TVES) with oxidized surfaces of silicon and aluminium was investigated at room temperature by high resolution electron energy loss spectroscopy (HREELS) and reflection-absorption infrared spectroscopy (RAIRS). The molecular interaction was held under vacuum environment. The chemical state of the substrate surfaces was characterized before and after the alkoxysilane interaction by Auger electron spectroscopy (AES), HREELS or RAIRS. Under vacuum conditions, silica surfaces are chemically inactive to the TVES molecules contrarily to oxidized aluminium surfaces where adsorption is realized successfully. Differences among adsorption mechanisms on both substrates are discussed in light of Bronsted acid properties of the oxide surfaces and of the role of physisorbed water.

Zinc oxide (ZnO) films with well-controlled morphologies have been prepared by electrochemical deposition. A seed layer of nanocrystallites of ZnO was prepared from which ZnO nanowires were grown from a low concentration of ZnCl 2 . The nanowires are rough and dense and their superhydrophilicity is enhanced. A treatment with an alkylsilane (octadecylsilane) yields superhydrophobic surfaces with very high advancing and receding contact angles 173°/172° and a very low roll-off angle. Our superhydrophobic films are stable for more than 6 months.

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