No abstract

Polydopamine films have been introduced by Messersmith et al. as a possible "versatile" surface functionalization method allowing to coat the surface of almost all known materials even superhydrophobic surfaces. These new kinds of coatings also confer a plethora of functionalities to the coated materials owing to the complex chemistry of the catechol quinone moieties present on the surface of polydopamine. These coatings may hence become an interesting alternative to established surface coatings like selfassembled monolayers and polyelectrolyte multilayered films. In this review, we describe the knowledge acquired in the last 3 years about the deposition mechanisms of polydopamine films, their properties, and various applications in surface science at the nanoscale.

No abstract

Organosilicon layers were deposited on galvanized steel to give a protective coating against corrosion. HMDSO was atomized and injected into a DBD plasma at atmospheric pressure. Plasma‐polymerized HMDSO layers were different when HMDSO nanodroplets reacted directly in the plasma area or when such droplets reacted with the plasma once deposited on the surface. Addition of a plasma curing step was also studied. Influence of the deposition method on the properties of ppHMDSO layers was also studied. Layer structure was measured by SEM and interferometry, and its chemical structure was analyzed by FTIR and XPS. Corrosion resistance, which was measured by electrochemistry, was significantly increased when a plasma curing step was performed.

Plasma polymerized (pp) layers are promising owing to their ease of deposition. Moreover, incorporation of suitable nanoparticles into a polymer matrix can provide improved properties, for instance an increased corrosion resistance, to the final nanocomposite layer. The efficiency of such an incorporation is highly dependent of the layer structure in general, and more particularly of nanoparticles dispersion in the coating. The synthesis of a hybrid coating for anticorrosion purpose is described. Deposition of a plasma polymerized hexamethyldisiloxane (ppHMDSO) coating matrix with aluminum–cerium oxide nanoparticles incorporation is performed by means of an atmospheric pressure plasma reactor in a dielectric barrier discharge (DBD) configuration. Admixture of ethanol within hexamethyldisiloxane (HMDSO) is carried out in order to improve homogeneity and properties of the coating.

Bi 1-x Sb x ) 2 Te 3 thermoelectric thin films were deposited on stainless steel discs in 1 M perchloric acid and 0.1 M tartaric acid by pulse electrodeposition in order to optimize the grain growth. The influence of the electrolyte composition, the cathodic current density and the cathodic pulse time on film stoichiometry were studied. The results show that it is necessary to increase the Sb content in the electrolyte to obtain the (Bi 0.25 Sb 0.75 ) 2 Te 3 film stoichiometry. Pulse plating reduced the grain size and the roughness, compared with continuous plating. Thermoelectric and electrical properties were also studied and it was found that the Seebeck coefficient and electrical resistivity were related to two parameters: the cathodic pulse current density and the films thickness.

No abstract

International audienceWe study the influence of locally doped silicon substrates on the electroreduction of diazonium salts. Our results show that the reduction of diazonium salts occurs at moderate potentials compared to the flat band potential of the semiconducting electrode. The underlying doping directs the electrografting, preferentially over doped areas of the substrate. High resolution spatially resolved X-ray photoelectron spectroscopy analysis using a new X-ray photoelectron emission microscope (XPEEM) and soft X-ray synchrotron radiation yields the thickness of the native oxide of the micron scale doped pattern on the substrate. The results as a function of both parameters--reduction potential compared to the flat band potential and thickness of the oxide layer--are discussed. These new results are then compared to data obtained on the localized electrografting of vinylic monomers