Patterned PPy Polymer and PPy/Ag Nanocomposites Thin Films by Photo-DLICVD

This work deals with the deposition of both undoped (insulator) and extrinsically Ag-doped (conductive) polypyrrole (PPy) coatings by an original Photo-DLICVD process. The uniform and conformal coverage of PPy thin films on both Si(100) wafer and liquid micro-droplets forming blisters is investigated. A self-ordered surface patterning of the blisters is achieved and discussed in relation with the substrate nature. By changing the precursor chemistry in this CVD process, conductive PPy/Ag nanocomposite films are grown. First evidence for conductive behavior of these Ag-doped PPy coatings was found. The Ag nanoparticles (NPs) reveal 1D assembly at the ledges of crystal-like facets of micron size nanocomposite particles leading to more complex arrangements of the metal NPs in the hybrid PPy/Ag coatings

Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva

The paper is focused on elaboration of ZrO2 films on pure zirconium via anodizing inphosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. Thestructure and composition of the films were investigated using scanning electronicmicroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition ofthe oxides formed at both potentials can be identified as monoclinic ZrO2. In addition to Zrand O, the layers formed in phosphoric acid contain phosphorus originating from thephosphoric acid. When the phosphoric acid solution contains NaF, fluorine is alsoincorporated into the oxide layer. The oxides formed at a higher voltage have greaterroughness than those formed at 30 V. Anodized samples exhibit smaller current densitiesduring anodic polarization compared to the as-received zirconium covered with native oxide.Fil: Romonti, Daniela E.. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Gomez Sanchez, Andrea Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Milošev, Ingrid. Jožef Stefan Institute; EsloveniaFil: Demetrescu, Ioana. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Ceré, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Evidences for liquid encapsulation in PMMA ultra-thin film grown by liquid injection Photo-CVD

This paper deals with the characterization of ultra-thin films of PMMA grown by an original photoassisted Chemical Vapor Deposition process equipped with a pulsed liquid injection system to deliver the monomer. The nanometric thick films showed a good ability to encapsulate a liquid phase as microdroplets protected by a thin polymeric tight membrane in the form of blisters. Techniques that are capable to analyze these heterogeneous structures at micro- and nanoscopic scale such as Raman Confocal Spectroscopy and Atomic Force Microscopy were used to characterize these polymer films. The liquid droplets were found to be monomer encapsulated by a PMMA film. The specific properties of these ultra-thin films exhibit self-healing capabilities at microscopic scale making them attractive for functionalization of surfaces and interfaces

Novel Approach to Surface Plasmon Resonance: A Third Dimension in Data Interpretation Through Surface Roughness Changes

In a Surface Plasmon Resonance (SPR) experiment two key parameters are classically recorded: the time and the angle of SPR reflectivity. This paper brings into focus a third key parameter: SPR reflectivity. The SPR reflectivity is proved to be related to surface roughness changes. Practical investigations on i) gold anodizing and ii) polypyrrole film growth in presence of oxalic acid is detailed under potentiostatic conditions. These experimental results reveal the potential of using the SPR technique to investigate real-time changes both on the gold surface, but also in the gold film itself. This extends the versatility of the technique in particular as sensitive in-situ diagnostic tool

The biocompatibility of titanium in a buffer solution: compared effects of a thin film of TiO2 deposited by MOCVD and of collagen deposited from a gel

This study aims at evaluating the biocompatibility of titanium surfaces modified according two different ways: (i) deposition of a bio-inert, thin film of rutile TiO2 by chemical vapour deposition (MOCVD), and (ii) biochemical treatment with collagen gel, in order to obtain a bio-interactive coating. Behind the comparison is the idea that either the bio-inert or the bio-active coating has specific advantages when applied to implant treatment, such as the low price of the collagen treatment for instance. The stability in buffer solution was evaluated by open circuit potential (OCP) for medium time and cyclic voltametry. The OCP stabilized after 5104 min for all the specimens except the collagen treated sample which presented a stable OCP from the first minutes. MOCVD treated samples stabilized to more electropositive values. Numeric results were statistically analysed to obtain the regression equations for long time predictable evolution. The corrosion parameters determined from cyclic curves revealed that the MOCVD treatment is an efficient way to improve corrosion resistance. Human dermal fibroblasts were selected for cell culture tests, taking into account that these cells are present in all bio-interfaces, being the main cellular type of connective tissue. The cells grew on either type of surface without phenotype modification. From the reduction of yellow, water-soluble 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT cytotoxicity test), MOCVD treated samples offer better viability than mechanically polished Ti and collagen treated samples as well. Cell spreading, as evaluated from microscope images processed by the program Sigma Scan, showed also enhancement upon surface modification. Depending on the experimental conditions, MOCVD deposited TiO2 exhibits different nanostructures that may influence biological behaviour. The results demonstrate the capacity of integration in simulated physiologic liquids for an implant pretreated by either method

Sustainable Coatings on Metallic Alloys as a Nowadays Challenge

Starting with a description of the meaning of sustainable coating nowadays, this review presents a selection of methods for sustainable coatings manufacture using raw materials, saving energy and costs. This selection creates an introduction for the coatings performances of intensively investigated coated alloys and their multifunctionality. There are many examples and EU recommendations to be discussed, and we especially chose to introduce sustainable coatings with both industrial and medical functions, such as bioinspired films and coatings on high-entropy alloys, biodegradable metallic alloys, etc. A special focus is on nanotechnology and nanomaterials in green procedures, enhancing coatings’ multifunctionality, introducing green corrosion inhibitors, smart additives, and coatings based on superhydrophobicity. The conclusions and future perspectives of sustainable and multifunctional coatings, as expressions of sustainable advanced materials, are based on important motivations of such studies

Preparation and characterization of MOCVD-fabricated TiO2: thin films deposited on titanium for biomedical applications

Titanium oxide (TiO2) thin films devoted to biomedical application were obtained by the chemical vapour deposition method. The films were deposited on titanium substrate using a low-pressure reactor with various precursor molar fractions and deposition temperatures. The influence of these parameters on film properties xas studied by using electron microscopy images, roughness measuring, X-ray diffraction, contact angle measuring and cyclic polarisation tests

Du tri-isopropoxyde aux oxydes d'aluminium par dépôt chimique en phase vapeur (procédé, composition et propriétés des revêtements obtenus)

Des revêtements d'alumine préparés par MOCVD à partir d'isopropoxyde d'aluminium (réacteur à mur chaud, basse pression, température de dépôt entre 350 et 700C) ont été caractérisés par EDS, EMPA, ERDA-RBS, DRX, MEB, MET, FTIR, ATG, AFM. La composition des dépôts préparés par pyrolyse du précurseur dans l'azote sec est AlO(OH) (amorphe) a 350C, Al203 (amorphous or nanocristallin) au dessus de 415C. Le dépôt en présence de vapeur d'eau conduit à la formation de Al203 uniquement. L'évolution microstructurale des dépôts a été étudiée par la technique de déflexion de lames asymétriquement revêtues, et par MET. Des essais de corrosion en solution et de corrosion sous contrainte effectués sur des alliages de titane Ti6242 revêtus d'alumine mettent en évidence un comportement électrochimique et des aptitudes de barrière très prometteurs, au niveau des meilleurs revêtements protecteurs testésThis film of alumina were prepared by MOCVD from aluminium isopropoxyde (hot-wall reactor, low-pressure, deposition temperature in range 350-700C. there were characterized by EDS, EMPA, ERDA-RBS, XRD, SEM, TEM, FTIR, TGA, AFM. The composition of films prepared by pyrolyzing the precursor in dry nitrogen is AlO(OH) (amorphous) at 350C, and Al2O3 (amorphous or nanocrystalline) above 415C. Deposition in the presence of water vapour yields Al2O3 only. Microstructural changes in the films were studied through the technique of deflection applied to asymmetrically coated blades, and by the transmission electron microscopy. Wet corrosion test and stress corrrosion cracking tests on coated Ti6242 alloys have shown the above described alumina coatings to behave like the best known protective coatings regarding both the electrochemical behaviour and the barrier propertiesTOULOUSE-ENSIACET (315552325) / SudocSudocFranceF