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International audience; An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionalization of graphite using two consecutive plasma treatments before immobilization of laccase as a biocatalyst to perform oxygen reduction reaction (ORR) by direct electron transfer ((DET). Nano-structuration of graphite surfaces by synthesis of vertical graphen-like carbon nanowalls (CNWs) was performed by microwave excited plasma enhanced chemical vapor deposition (PECVD). Atmospheric pressure plasma jet (APPJ) system was then used to functionalize chemically the CNWs surface via a rapid and dry route. A partial fractional design evidenced two significant parameters of the APPJ treatment in terms of ORR current density: the treatment time and the inter-distance between the plasma jet and the surface of the carbon material. With the optimized APPJ treatment parameters, a four-fold enhancement of the ORR current density (-440 ± 70 µA/cm2) could be obtained on CNWs, compared to graphite electrodes. The best current density obtained was about −1 mA/cm2 with oxidized laccase covalently immobilized on the electrode without any agitation of the solution, confirming the main importance of enzyme orientation on the electrode surface for efficient DET transfer, the relevance of electrode nanostructuration and the advantage of covalent linking of the protein on the electrode surface.

International audience; Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a dielectric barrier discharge at atmospheric pressure. Commercially available GNs were incorporated into HMDSO precursor at different concentrations up to 2 wt%. The nanocomposite coatings were analyzed using scanning electron microscopy (SEM) and nanoindentation test. Based on SEM images, it was found that the GNs were well distributed and dispersed in the plasma polymerized hexamethyldisiloxane (ppHMDSO) matrix with no significant agglomeration. The results of nanoindentation tests performed with the continuous stiffness measurements mode showed an increase in the hardness and reduced Young's modulus with the increase of graphene nanosheets percentage. The maximum increase was two orders of magnitude for 2% GNs/ppHMDSO nanocomposite coatings compared to the homopolymer ppHMDSO. Furthermore, the creep compliance analysis showed that the nanocomposite coatings exhibited a viscoelastic behavior compared to the plasma polymer homopolymer.

"The final publication is available at link.springer.com"; International audience; In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred hydrophilic functional groups onto the surface, which lead to enhanced bioactivity of UHMWPE without affecting the biocompatibility of the polymer. The latter was checked by increased adhesion of fibroblast cells to the polymer. The effects of the He/2% O2 DBD plasma was compared for the first time to a rotating blown arc atmospheric pressure plasma jet (r-APPJ) in air. The results show a better functionalization as well as stability of the surface properties of the films treated with the DBD. The surface modified UHMWPE once immersed in a Simulated Body Fluid induced the formation of nucleus of hydroxyapatite (calcium phosphate) leading to the growth of a thick apatite coating which was followed up to 14 days, which can be expected to be highly bioactive. Surface characterization techniques also showed different chemical moieties in the case of the two different atmospheric discharges. DBD discharge in He/2% O2, leading to more stable polar functions grafted to a crosslinked polymer surface, proved to be more bioactive than UHMWPE treated by a r-APPJ in air. The latter treatment lead to grafting of less oxygen containing groups to the surface as well as to LMWOM created on r-APPJ treated UHMWPE which are unstable in aqueous media used both in SBF and fibroblasts in DMEM.

Plasma processing finds widespread biomedical applications, such as the design of biosensors, antibiofouling surfaces, controlled drug delivery systems, and in plasma sterilizers. In the present coronavirus disease (COVID‐19) situation, the prospect of applying plasma processes like surface activation, plasma grafting, plasma‐enhanced chemical vapor deposition/plasma polymerization, surface etching, plasma immersion ion implantation, crosslinking, and plasma decontamination to provide timely solutions in the form of better antiviral alternatives, practical diagnostic tools, and reusable personal protective equipment is worth exploring. Herein, the role of nonthermal plasmas and their contributions toward healthcare are timely reviewed to engage different communities in assisting healthcare associates and clinicians, not only to combat the current COVID‐19 pandemic but also to prevent similar kinds of future outbreaks., This review presents a comprehensive take on the significance of nonthermal plasma processing as a versatile tool for developing state‐of‐the‐art biomedical and healthcare technologies. Under the spotlight is its immense technological potential to offer apposite solutions for combating viral pandemics like coronavirus disease (COVID‐19), be it in the form of rapid diagnostic tools fabrication, sterilized personal protective equipments (PPEs), drug delivery systems, or antimicrobial and antibiofouling surfaces.

Background It may be impossible to perform cancer surgery with free margins in the presence of an unresectable structure. Local drug treatment after surgery has been proposed to increase the rate of tumor control. Methods Multi-nanolayers (10-330 nm) were generated by a low-pressure (375mTorr) inductively coupled plasma (13.56 MHz) reactor for anticancer drug delivery by the deposition of polycaprolactone-polyethylene glycol multistack barrier on the collagen membrane (100 μm thickness). Carboplatin (300 μg/cm2) was used for the in vitro and in vivo investigations. Energy-dispersive X-ray spectroscopy (15 keV), scanning electron microscopy and inductively coupled plasma mass spectrometry were used to detect the presence of carboplatin in the nanolayer, the tumor sample and the culture medium. Preclinical studies were performed on ovarian (OVCAR-3NIH) and colon (CT26) cancer cell lines as xenografts (45 days) and allografts (23 days) in Swiss-nude (n = 6) and immunocompetent BALB/cByJ mice (n = 24), respectively. Results The loading of carboplatin or other drugs between the nanofilm on the collagen membrane did not modify the mesh complex architecture or the drug properties. Drugs were detectable on the membrane for more than 2 weeks in the in vitro analysis and more than 10 days in the in vivo analysis. Cytotoxic mesh decreased cell adherence (down 5.42-fold) and induced cancer cell destruction (up to 7.87-fold). Implantation of the mesh on the mouse tumor nodule modified the cell architecture and decreased the tumor size (50.26%) compared to the control by inducing cell apoptosis. Conclusion Plasma technology allows a mesh to be built with multi-nanolayer anticancer drug delivery on collagen membranes.

International audience; In this study, micrometer thick Ag‐TiO2 coatings were deposited in a single and facile step by spraying the precursor in an atmospheric pressure plasma jet with different concentrations of Ag nanoparticles. The homogenous distribution of Ag decreased the TiO 2 crystal size and increased the surface area. The coatings were characterized to be porous with an anatase phase with improved charge separation and visible light absorption. The photocatalytic activity of the materials was investigated for degrading rhodamine B using a white lamp as a screening method to optimize Ag‐TiO 2 coatings. Then the photodegradation of trace pharmaceutical compounds (TrPCs) was investigated by using a solar light simulator at the optimal condition of a TiO 2 coating with 0.4wt% Ag

International audience; This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, fomic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1 ± 0.2 nm was synthesized at 126 °C, 15 M NaOH and 49 g L−1 TiO2. The maximum H2 production rate of 475 ± 12 μmol·h−1 (quantum efficiency (ε) = 20.2 ± 0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, fomic acid and 1,2,3 propanetriol.

International audience; The present study proposes an alternative eco-friendly method to prepare a thin composite coating based on graphene embedded in siloxane polymers which can be used as application for the corrosion protection of steel. The nanocomposite coatings were elaborated by a dielectric barrier discharge using a nebulized colloidal suspension of graphene nanosheets (GNs) dispersed in hexamethyldisiloxane (HMDSO) used as the precursor for the polymer matrix. After obtaining a stable colloidal solution, it was nebulized into the plasma reactor to form a plasma polymer (pp) coating from HMDSO (ppHMDSO) in which GNs were incorporated (GN@ppHMDSO) on the mild steel substrate. The chemical structure of the hybrid coatings was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry. Raman spectra of GNs and GN@ppHMDSO coatings suggest the existence of charge transfer between the GNs and the HMDSO matrix. Furthermore, scanning electron microscopy confirms the synthesis of micro/nanocomposite with a fairly homogeneous dispersion of the GNs in the polymer matrix. The corrosion resistance of the samples was evaluated by electrochemical impedance spectroscopy which showed that the hybrid coatings GN@ppHMDSO deposited by a one-step atmospheric pressure plasma process, presented excellent anticorrosion performance with 99.99% of protection efficiency.

International audience; One-dimensional TiO2 nanostructure synthesized using a hydrothermal method showed significant differences in the bandgap energies and crystal phase properties under different synthesis conditions. The objectives of this study were to evaluate the effect of the hydrothermal reaction conditions on the bandgap energy and to optimize the reaction conditions using a 3-factor 3-level Box Behnken design. The factors investigated include temperature, NaOH concentration and TiO2 concentration (BBD). A quadratic response surface model predicted optimum conditions for the maximum and minimum bandgap energy. The BBD analysis and other statistical tools provided evidence showing the temperature and NaOH concentration significantly affected the 1D TiO2 bandgap energy. Pure anatase was associated with a higher bandgap energy, whereas the biphasic anatase-rutile and anatase-TiO2-B phases were linked with decreasing the bandgap energy. In addition, the crystal size and specific surface area (SSA) impact on the bandgap energy was due to the size quantization effect.

International audience; Enhanced TiO2 nanorods (TNRs) with partially reduced graphene oxide (RGO) (designated as GT) were prepared for degrading aqueous hazardous pollutants. The degree of RGO oxidation had an important role in affecting the photoelectronic and photocatalytic activities of GT composites. The study examined the impact of the degree of RGO oxidation on the photocatalytic activities. The photocatalytic activity of the materials was investigated for degrading rhodamine b (RhB), methyl orange (MO), methylene blue (MB), and phenol by using ultraviolet (UV) light. The highest photocatalytic activity was observed when the atomic oxygen-to-carbon (O/C) ratio of RGO was 0.130 ± 0.003. This study suggested the photocatalytic performance was maximized by preserving a selected amount of the RGO oxygen-containing groups. The work reported in this study on optimizing the RGO-based TiO2 photocatalyst could serve as a promising approach for preparing and optimizing other types of carbon-based photocatalysts such as graphene-based CdS.

International audience; Quasi-one-dimensional (Q1D) titanium dioxide (TiO2) nanomaterials have attracted attention inphotocatalytic applications because of their high oxidative potential coupled with increasing activesites. In this study, Q1D TiO2 samples with different phase structure, crystal size, and specific surfacearea were produced using a hydrothermal method by varying the reaction conditions (temperature,alkaline concentration, and the TiO2 precursor concentration). A three-factor three-level Box–Behnkendesign (BBD) with three replicates (15 conditions) at the center point was employed to evaluateand optimize the hydrothermal synthesis factors in terms of photocatalysis of rhodamine B (RhB),phenol, methyl orange, and methylene blue. The BBD demonstrated that the temperature and theNaOH concentration significantly affected the Q1D TiO2 crystal size, phase structure, bandgap, andphotocatalytic activity. A reduce temperature at 120°C and a low NaOH concentration at 5 M werefavorable in producing a biphasic anatase–rutile structure with optimum photocatalytic activity.Under a higher temperature of 190°C and with ≥ 10 M NaOH concentration, the presence of TiO2-Bphase resulted in the lowest photocatalytic activity.

International audience; SiOx films were deposited using an atmospheric-pressure transporting discharge, and we adopted tetraethyl orthosilicate (TEOS) as the precursor. We studied the effects of nozzle-substrate distance, applied power, deposition time, and precursor inlet positions on the substrates placed at the tube exit. The deposited thin films were investigated using field-emission scanning electron microscopy and attenuated total-reflection Fourier-transform infrared spectroscopy. The specific studies that we carried out showed a clear relationship between the operating parameters of the deposition process and the morphological and chemical properties of the deposited films. In addition to samples treated outside of the tube in the jet mode, transporting discharge was used to deposit SiOx thin films inside fluorinated ethylene propylene (FEP) tubes. Changing the chemistry inside the FEP tubes completely modified the interaction of CT-26 cells; that is, the nonadhesive FEP tubes became completely adhesive. This study shows the potential for modifying surfaces properties inside tubes for different biological applications.

International audience; N-doped TiO2 thin films have been prepared by reactive RF magnetron sputtering at different pressures and with different compositions using a dual reactive gas mixture of nitrogen and oxygen. The morphological, optical, photo-electrochemical and photocatalytic properties have been studied in order to investigate the white light and visible light photoactivities of the films. Significant control over the band gap energy in the films was achieved by varying the deposition parameters. Photoelectrochemical characterization revealed improved white light photocurrent generation in nitrogen doped films prepared at low pressures. However, the visible light photocurrent generation showed improvement for all deposition pressures, and changed accordingly with the nitrogen incorporation. Photocatalytic measurements of a common chemical pollutant NMP (N-methyl-2-pyrrolidone) under different irradiation conditions provided evidence of improved photoactivity for samples prepared at high pressure, due to the increased active surface area and optimal nitrogen doping levels. Overall, this study showed a simple method to produce highly controllable nitrogen doping in different sites within TiO2 showing improved visible light photoactivity and photo induced pollutant degradation. More interestingly, by investigating the effect of different nitrogen sites in nitrogen doped TiO2, we have shown that the optimized conditions for photocatalysis do not correspond to those for water splitting.

International audience; Thin films of fluorocarbon were deposited on polyethersulfone membranes via argon plasma sputtering of a poly(tetrafluoroethylene) (PTFE) target in an RF magnetron plasma reactor. The obtained deposited ultrathin coatings had nanoscale roughnesses and high degrees of fluorination. The intensity of fluorine atom in plasma environment during fluorocarbon deposition was investigated. Depending on the deposition conditions comprising working gas pressure, applied RF power, and distance between the target and the substrate, polymeric films with different chemical compositions and/or morphologies were obtained. The morphologies of the films were analyzed by means of SEM, XPS, and AFM. The results suggested that the sputtered film deposited at a higher pressure and longer target–substrate distance and moderate RF power had a surface composition and chemical structure closer to those of the PTFE film. The treated hydrophobic PES membranes with water contact angles as high as 115° were applied for the first time in an air gap membrane distillation setup for removal of benzene as a volatile organic compound from water. The results showed that the plasma-treated membranes have a comparable or superior performance to that of commercial PTFE used in membrane distillation with similar permeate flux and separation factor after 20 h long term performance.

International audience; In this article, we developed transporting plasma sources that operate at atmospheric pressure. The effect of electrode configuration on plasma transporting was investigated. In order to increase the transporting plasma cross-section, we converted a plasma stream into four plasma channels by a cylindrical housing. Electron excitation and rotational temperatures were estimated using optical emission spectroscopy. Furthermore, the electrical and temporal characteristics of the plasma, discharge power and charge deposition on the target were investigated. The propagation characteristics of single and multi-channel transporting plasma were compared with the same cross-sectional area. Two configurations for multi-channels were designed for this purpose. Escherichia coli bacteria were exposed to the single and multi-channel transporting discharge for different time durations. After exposure, the results indicated that the inactivation zones were significantly increased by a multi-channel transporting plasma. Finally, E. coli inactivation by those plasma apparatuses was compared with that of several standard antimicrobial test discs such as Gentamicin, Tetracycline, Amoxicillin and Cefixime.

The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmospheric pressure rotating plasma jet (APPJ) and the surface modifications were studied to assess its hydrophilicity and adhesion to acrylic adhesive tape intended for medical applications. Furthermore, the extent of hydrophobic recovery under different storage conditions was studied. The surface treatment of PDMS with the APPJ under optimal conditions noticeably increased the oxygen content and most of the surface silicon species were fully oxidized. A brittle silica-like layer on the outermost surface was created showing changes in topography due to the formation of grooves and cracks. A huge improvement in T-peel and the shear adhesive strength of the APPJ-treated PDMS surface/acrylic tape joints was obtained. On the other hand, the hydrophilicity of the PDMS surface increased noticeably after the APPJ treatment, but 24 h after treatment almost 80% hydrophobicity was recovered and the adhesive strength was markedly reduced with time after the APPJ treatment. However, the application of an acrylic adhesive layer on the just-APPJ-treated PDMS surface retained the adhesive strength, limiting the extent of hydrophobic recovery. The STSM Grant by COST ACTION MP1101 ‘Biomedical Applications of Atmospheric Pressure Plasma Technology’ and financial support from the Innovaciones DisRas S L Company is gratefully acknowledged.

Thin films of TiN were prepared via RF magnetron reactive sputtering at various deposition pressures. The characteristics of the plasmas were measured by optical emission spectroscopy to optimize the conditions for the deposition of TiN coatings. After deposition, the thin films were annealed in a closed furnace at several different temperatures, and revealed the formation of different phases of TiO2. The resulting TiN/TiO2 thin films showed drastic changes in their crystal structure, optical properties, and photoelectrochemical performance. By examining how the deposition pressure and postdeposition annealing conditions affected the TiN film structure and performance, samples were prepared to optimize visible light absorption and activity. A model for the oxidation process was proposed which described the structural change from TiN to TiO2 through optical, morphological, and crystalline characterization. This study has systematically shown the ability to tailor the optical, crystalline, and photoactive p...

International audience; Multi-layered thin films of TiO 2 and TiN were created by RF reactive magnetron sputtering and were compared with homogeneous thin films of N doped TiO 2 having the same thickness. The crystalline, chemical, optical and photoactive properties were measured and discussed in detail. The number of bilayers was kept constant either 9 or 18 bilayers, but the overall composition (TiN to TiO 2 ratio) was varied. The TiN and TiO 2 layer thicknesses were controlled systematically in order to produce films with TiN to TiO 2 ratio ranging from 5% to 28%. The TiN/TiO 2 ratio was controlled for both bilayers in order to get the best synergic effect of light absorption/reflection and charge separation based on the generation of the photo-electrochemical current and the photocatalytic activity under UV and visible light. A maximum photocurrent generation was found for thin films having a TiN/TiO 2 ratio of 21% and 28% for the 9 bilayer and the 18 bilayer films, respectively. The superiority of the configuration of the 18 bilayer has been confirmed by studying the photocatalytic activity. The photoactive improvement of the bilayered thin films as compared to non-doped TiO 2 is the result of the enhanced charge separation at the heterogeneous junction, interfacial effects between TiN and TiO 2 , which is found to depend on the thickness of the TiN layers. Electronic as well as optical approaches have been presented to explain the superiority of the bilayers strategy. This study has shown that a bilayered morphology of TiN and TiO 2 can significantly enhance the photocatalytic and photoelectrochemical behavior of TiO 2 under visible light illumination conditions which is applicable to numerous fields.

International audience; In this paper, it is reported that composition of an atmospheric pressure nitrogen plasma jet is influenced by the nozzle material. Using optical emission spectroscopy and camera observations, it is shown that using a stainless steel nozzle, induces an orange nitrogen emission, whereas a quartz nozzle leads to blue nitric oxide emission, due to the nitridation and oxygen exchange between the reactive nitrogen plasma and the SiO2 surface.

International audience; A simple method to deposit photocatalytic TiO2 coatings, at a high rate (20–40μms−1), andwith a high porosity, is reported in this paper. This method, which allows the treatment ofmembranes (with an 800 nm pore size), is based on the introduction of a liquid precursorsprayed into an open-air atmospheric pressure plasma jet (APPJ). The photocatalytic activityof the TiO2 thin films prepared by APPJ have been compared with our best N-doped TiO2 thinfilms, deposited by reactive radio frequency (RF) magnetron sputtering, previously reported inthe literature. The morphology, chemical composition, photoelectrochemical, andphotocatalytic properties of the coatings have been studied in this paper. Significant control ofthe porosity and crystallinity was achieved by varying the deposition parameters and theannealing temperature. Under optimized conditions, the TiO2 coatings deposited by APPJ arecharacterized by a higher photocatalytic activity as compared to the optimized thin filmsdeposited by RF sputtering. This difference can be explained by the higher specific surface ofthe APPJ coatings. Finally, the most interesting characteristic of this APPJ-liquid spray processis its capacity to treat membranes without blocking the pores, and to produce photocatalyticmembranes which can efficiently combine filtration and photocatalysis for water treatment.

The thin film deposition in DBDs fed with Ar/HMDSO/O2 mixtures was studied by comparing the FT-IR spectra of the deposits with the GC-MS analyses of the exhaust gas. Under the experimental conditions investigated, oxygen addition does not enhance the activation of the monomer while it highly influences the chemical composition and structure of the deposited coating as well as the quali-quantitative distribution of by-products in the exhaust. Without oxygen addition a coating with high monomer structure retention is obtained and the exhaust contains several by-products such as silanes, silanols, and linear and cyclic siloxanes. The dimethylsiloxane unit seems to be the most important building block of oligomers. Oxygen addition to the feed is responsible for an intense reduction of the organic character of the coating as well as for a steep decrease, below the quantification limit, of the concentration of all by-products except silanols. Some evidences induce to claim that the silanol groups contained in the deposits are formed through heterogeneous (plasma-surface) reactions.

International audience; SnO2:F thin films were deposited on polycarbonate and glass substrates by RF capacitively coupled plasma enhanced chemical vapor deposition (PECVD) using a mixture of tetramethyltin (TMT) [Sn(CH3)4], argon, oxygen as precursors. The effects of the substrate temperature, deposition time and doping on the resistivity and the morphology of the films have been studied. The as-deposited films appear to have higher carrier mobilities than amorphous ones, in the range of 5 and 7.5 cm2 · V−1 · s−1, which could be explained by the presence of nanocrystallites. In order to understand the nanostructure of the films, we studied the formation of nanoparticles and dust particles in the discharge. Finally, we have shown that the incorporation of less than 3% of F in the tin oxide layer could decrease the resistivity down to 3 · 10−3 Ω · cm.

In this thesis, graphene-based nanocomposite thin films were developed for the first time bynon-equilibrium atmospheric plasma to improve the corrosion resistance properties of E24carbon steel and 2024 aluminum. A specific strategy was proposed and consists in atomizing apolymerizable colloidal suspension via a nebulizer into the discharge zone to obtainnanocomposite layers in a single step. Two types of plasma discharge have been studied, adielectric barrier discharge (DBD) and a plasma jet (APPJ), for the growth of nanocompositelayers with an organosilicon matrix from a colloidal solution obtained by dispersing graphenenanosheets in a hexamethyldisiloxane solution (HMDSO). The coatings were characterized bySEM, FTIR, XPS and Raman as a function of the plasma discharge parameters such as power,plasma gas and monomer flow rates and treatment time. The analyses show a homogeneousdispersion of the graphene sheets in the polymer matrix, and the coatings obtained by DBD areless porous and have a more organic character than those obtained by APPJ. The anti-corrosionproperties of the nanocomposites were evaluated by electrochemical impedance spectroscopyand show an improvement of the corrosion protection effect, with an increase under optimalconditions of up to 3 orders of magnitude in the resistance to charge transfer on treated steel.The results obtained in this thesis demonstrate that the incorporation of graphene nanosheets inthe plasma polymer matrix has the effect of reducing the porosity of the layers, increasing thecorrosion resistance, and also improving the hardness and elastic modulus of thenanocomposites which are important points for industrial applications.; Dans cette thèse, des couches minces nanocomposites à base de graphène ont été élaborées pourla première fois par plasma atmosphérique hors équilibre pour améliorer les propriétés derésistance à la corrosion de l’acier au carbone E24 et de l’aluminium 2024. Une stratégiespécifique a été mise en oeuvre et consiste à atomiser une suspension colloïdale polymérisablevia un nébuliseur dans la zone de décharge plasma pour obtenir en une seule étape des couchesnanocomposites. Deux types de décharge plasma ont été étudiées, une décharge à barrièrediélectrique (DBD) et un jet de plasma (APPJ), pour la croissance de couche nanocomposites àmatrice organosilicié à partir d’une solution colloïdale obtenue par dispersion de feuillets degraphène dans une solution d’hexaméthyldisiloxane (HMDSO). Les revêtements ont étécaractérisés par MEB, FTIR, XPS et Raman en fonction des paramètres de la décharge plasmatels que la puissance, les débits de gaz plasmagène et de monomère et le temps de traitement.Les analyses montrent une dispersion homogène des feuillets de graphène dans la matricepolymère, et les dépôts obtenus par DBD sont moins poreux et ont un caractère plus organiqueque ceux obtenus par APPJ. Les propriétés anticorrosion des nanocomposites ont été évaluéespar spectroscopie d’impédance électrochimique et mettent en évidence l’augmentation del’effet protecteur contre la corrosion, avec une augmentation jusqu’à 3 ordres de grandeur de larésistance au transfert de charge sur l’acier traité. Les résultats obtenu dans cette thèsepermettent de démontrer que l’incorporation de feuillets de graphène dans la matrice depolymère plasma a pour effet de diminuer la porosité des couches, d’augmenter la résistance àla corrosion, et d’améliorer également la dureté et le module élastique des nanocomposites cequi constitue un aspect important pour les applications industrielles.

In this thesis, graphene-based nanocomposite thin films were developed for the first time bynon-equilibrium atmospheric plasma to improve the corrosion resistance properties of E24carbon steel and 2024 aluminum. A specific strategy was proposed and consists in atomizing apolymerizable colloidal suspension via a nebulizer into the discharge zone to obtainnanocomposite layers in a single step. Two types of plasma discharge have been studied, adielectric barrier discharge (DBD) and a plasma jet (APPJ), for the growth of nanocompositelayers with an organosilicon matrix from a colloidal solution obtained by dispersing graphenenanosheets in a hexamethyldisiloxane solution (HMDSO). The coatings were characterized bySEM, FTIR, XPS and Raman as a function of the plasma discharge parameters such as power,plasma gas and monomer flow rates and treatment time. The analyses show a homogeneousdispersion of the graphene sheets in the polymer matrix, and the coatings obtained by DBD areless porous and have a more organic character than those obtained by APPJ. The anti-corrosionproperties of the nanocomposites were evaluated by electrochemical impedance spectroscopyand show an improvement of the corrosion protection effect, with an increase under optimalconditions of up to 3 orders of magnitude in the resistance to charge transfer on treated steel.The results obtained in this thesis demonstrate that the incorporation of graphene nanosheets inthe plasma polymer matrix has the effect of reducing the porosity of the layers, increasing thecorrosion resistance, and also improving the hardness and elastic modulus of thenanocomposites which are important points for industrial applications.; Dans cette thèse, des couches minces nanocomposites à base de graphène ont été élaborées pourla première fois par plasma atmosphérique hors équilibre pour améliorer les propriétés derésistance à la corrosion de l’acier au carbone E24 et de l’aluminium 2024. Une stratégiespécifique a été mise en oeuvre et consiste à atomiser une suspension colloïdale polymérisablevia un nébuliseur dans la zone de décharge plasma pour obtenir en une seule étape des couchesnanocomposites. Deux types de décharge plasma ont été étudiées, une décharge à barrièrediélectrique (DBD) et un jet de plasma (APPJ), pour la croissance de couche nanocomposites àmatrice organosilicié à partir d’une solution colloïdale obtenue par dispersion de feuillets degraphène dans une solution d’hexaméthyldisiloxane (HMDSO). Les revêtements ont étécaractérisés par MEB, FTIR, XPS et Raman en fonction des paramètres de la décharge plasmatels que la puissance, les débits de gaz plasmagène et de monomère et le temps de traitement.Les analyses montrent une dispersion homogène des feuillets de graphène dans la matricepolymère, et les dépôts obtenus par DBD sont moins poreux et ont un caractère plus organiqueque ceux obtenus par APPJ. Les propriétés anticorrosion des nanocomposites ont été évaluéespar spectroscopie d’impédance électrochimique et mettent en évidence l’augmentation del’effet protecteur contre la corrosion, avec une augmentation jusqu’à 3 ordres de grandeur de larésistance au transfert de charge sur l’acier traité. Les résultats obtenu dans cette thèsepermettent de démontrer que l’incorporation de feuillets de graphène dans la matrice depolymère plasma a pour effet de diminuer la porosité des couches, d’augmenter la résistance àla corrosion, et d’améliorer également la dureté et le module élastique des nanocomposites cequi constitue un aspect important pour les applications industrielles.

This dissertation is focused on synthesizing Q1D TiO2-based nanocatalysts for degrading aqueous organic pollutants and producing H2. A facile alkaline hydrothermal process was used to synthesize Q1D TiO2 under different hydrothermal synthesis factors (reaction temperature, NaOH concentration and TiO2 precursor concentration). The hydrothermal synthesis factors significantly affected the Q1D TiO2 phase structure, crystal size, specific surface area (SSA), bandgap, photocatalytic activities. A Box-Behnken design (BBD) model was used to optimize the hydrothermal factors for synthesizing Q1D TiO2 with maximum photodegradation rate and H2 production rate. The optimized Q1D TiO2 with maximum photodegradation rate was further enhanced with partially reduced graphene oxide (RGO) (designated as GT) for degrading aqueous hazardous pollutants. The study also examined the impact of the RGO atomic oxygen-to-carbon (O/C) ratio on GT photocatalytic activities. The highest photocatalytic activity was observed when the RGO atomic O/C ratio was 0.130±0.003. Next, the GT photocatalyst was enhanced with Ag NPs (designated as Ag-GT). The highest photocatalytic activity was observed for a silver content of 10 wt% in the photocatalyst film. Finally, an atmospheric pressure plasma jet (APPJ) was employed to synthesize micrometer thick Ag nanoparticles modified TiO2 (Ag-TiO2) coatings, presenting a core-shell structure for degrading RhB and trace pharmaceutical compounds using a solar light source. The Ag-TiO2 coatings were characterized having a porous anatase phase, improved charge separation and visible light absorption. The highest photodegradation rate was observed for a silver content of 0.4wt% in the composite. Cette thèse porte sur la synthèse des nanocatalyseur à base de TiO2 Q1D (quasi-unidimensionnel) pour dégrader des polluants organiques aqueux et pour produire de l’hydrogène. Un processus hydrothermal alcalin simple a été utilisé pour synthétiser TiO2 Q1D avec des paramètres de synthèse différents (la température, la concentration de NaOH de précurseur TiO2). Ces paramètres affectent la structure de phase de TiO2 Q1D, la taille du cristal, la surface spécifique (SS), l'énergie du gap et les activités photocatalytiques qui en résultent. Le modèle Boîte-Behnken (BBD) est utilisé pour optimiser les paramètres hydrothermaux permettant d’obtenir un taux de photodégradation maximal des polluants étudiés, et un taux de production d’H2 maximal. Le TiO2 Q1D optimisé a été davantage amélioré à l’aide d’oxyde de gràphène partiellement réduit (RGO) pour obtenir le catalyseur désigné GT. L’impact du rapport atomique O/C du RGO sur l’activité catalytique du GT est étudié. La valeur maximale d’activité photocatalytique est obtenu pour O/C =0.130±0.003. Puis, le GT est amélioré avec les NP d’Ag (Ag-GT). L’activité maximale est obtenue pour 10%d’Ag. Enfin un jet plasma atmosphérique (APPJ) a été employé pour synthétiser des couches minces nanométriques de TiO2 avec inclusion des NP d’Ag de structure cœur-coquille pour la dégradation du colorant RhB et des différents des produits pharmaceutiques à l’aide d’un simulateur solaire. Les couches composites minces (Ag-TiO2) sont très poreuses de phase anatase avec une absorption dans le visible et une amélioration de la séparation des charges. La valeur maximale de la photo-dégradation a été obtenue pour 0.4% d’Ag dans la couche composite.

This dissertation is focused on synthesizing Q1D TiO2-based nanocatalysts for degrading aqueous organic pollutants and producing H2. A facile alkaline hydrothermal process was used to synthesize Q1D TiO2 under different hydrothermal synthesis factors (reaction temperature, NaOH concentration and TiO2 precursor concentration). Hydrothermal synthesis factors significantly affected the Q1D TiO2 phase structure, crystal size, specific surface area (SSA), bandgap, photocatalytic activities. A Box-Behnken design (BBD) model was used to optimize the hydrothermal factors for synthesizing Q1D TiO2 with maximum photodegradation rate and H2 production rate. The optimized Q1D TiO2 with maximum photodegradation rate was further enhanced with partially reduced graphene oxide (RGO) (designated as GT) for degrading aqueous hazardous pollutants. The study also examined the impact of the RGO atomic oxygen-to-carbon (O/C) ratio on GT photocatalytic activities. The highest photocatalytic activity was observed when the RGO atomic O/C ratio was 0.130±0.003. Next, the GT photocatalyst was enhanced with Ag NPs (designated as Ag-GT). The highest photocatalytic activity was observed for a silver content of 10 wt% in the photocatalyst film. Finally, an atmospheric pressure plasma jet (APPJ) was employed to synthesize micrometer thick Ag nanoparticles modified TiO2 (Ag-TiO2) coatings, presenting a core-shell structure for degrading RhB and different pharmaceutical compounds using a solar light source. Ag-TiO2 coatings were characterized having a porous anatase phase, improved charge separation and visible light absorption. The highest photodegradation rate was observed for a silver content of 0.4wt% in the composite.; Cette thèse porte sur la synthèse des nanocatalyseur à base de TiO2 Q1D (quasi-unidimensionnel) pour dégrader des polluants organiques aqueux et pour produire de l’hydrogène. Un processus hydrothermal alcalin simple a été utilisé pour synthétiser TiO2 Q1D avec des paramètres de synthèse différents (la température, la concentration de NaOH de précurseur TiO2). Ces paramètres affectent la structure de phase de TiO2 Q1D, la taille du cristal, la surface spécifique (SS), l'énergie du gap et les activités photocatalytiques qui en résultent. Le modèle Boîte-Behnken (BBD) est utilisé pour optimiser les paramètres hydrothermaux permettant d’obtenir un taux de photodégradation maximal des polluants étudiés, et un taux de production d’H2 maximal. Le TiO2 Q1D optimisé a été davantage amélioré à l’aide d’oxyde de gràphène partiellement réduit (RGO) pour obtenir le catalyseur désigné GT. L’impact du rapport atomique O/C du RGO sur l’activité catalytique du GT est étudié. La valeur maximale d’activité photocatalytique est obtenu pour O/C =0.130±0.003. Puis, le GT est amélioré avec les NP d’Ag (Ag-GT). L’activité maximale est obtenue pour 10%d’Ag. Enfin un jet plasma atmosphérique (APPJ) a été employé pour synthétiser des couches minces nanométriques de TiO2 avec inclusion des NP d’Ag de structure coeur-coquille pour la dégradation du colorant RhB et des différents des produits pharmaceutiques à l’aide d’un simulateur solaire. Les couches composites minces (Ag-TiO2) sont très poreuses de phase anatase avec une absorption dans le visible et une amélioration de la séparation des charges. La valeur maximale de la photo-dégradation a été obtenue pour 0.4% d’Ag dans la couche composite.

Cette thèse porte sur une étude fondamentale sur le dépôt des couches minces d'organosiliciés par des Décharges à Barrière Diélectrique (DBD), un procédé très intéressant pour l'application aux textiles. La plupart des dépôts des couches d'oxyde de silicium sont déposées à partir du précurseur hexaméthyle silixone (HMDSO).De plus très peu d'études sont consacrées aux mécanismes de dépôt des couches à la pression atmosphérique. Dans cette étude les propriétés des couches minces déposées par DBD alimentées par Ar/HMDSO/O2, Ar/PMDSO (pentaméthyldisiloxane)/O2 et Ar/TMDSO (tetraméthyldisiloxane)/O2, avec différentes proportions de l'oxygène, ont été confrontées aux analyses, par GC-MS, des gaz sortant du réacteur. Nous avons trouvé que l'ajout d'O2 au gaz d'alimentation n'améliore pas l'activation du précurseur organosilicié, même s'il augmente la puissance injectée. En revanche il influence fortement la composition chimique des dépôts et favorise une forte réduction de la concentration des sous-produits dans le gaz sortant du réacteur. Sans ajout de l'O2, des couches minces obtenues contiennent beaucoup de carbone , avec rétention de la structure du précurseur de départ. En réduisant le nombre de -CH3 dans le précurseur (HMDSO>PMDSO>TMDSO), le nombre et l'abondance des sous-produits détectés dans le gaz sortant du réacteur diminuent fortement. Il semblerait que les unités de répétition diméthylsiloxane et hydrométhylsiloxane jouent un rôle important dans l'oligomérisation des trois précurseurs. Différents mécanismes d'activation, ainsi que différents procédés de formation des groupes Si-OH dans les dépôts, ont été proposés pour les trois précurseurs., No data