Summary: In this study, microstructured surfaces are produced by a spatial arrangement of different functional domains by a combination of plasma polymerization and photolithography. Two different kinds of protein and cell adhesive patterns have been alternated with non‐fouling areas. Non‐fouling patterns are made of poly(ethylene oxide) (PEO)‐like polymers obtained by pulsed plasma polymerization of diethylene glycol dimethyl ether, which leads to coatings with a high concentration of ethylene oxide groups (>70%). Fouling surfaces are composed of PEO coatings with a low concentration of ethylene oxide groups (≈40%) and films containing amino groups (from allylamine monomer) obtained by plasma polymerization. High pattern fidelity is demonstrated by ellispometry measurements, whereas XPS and ToF‐SIMS analyses have been used to characterize the surfaces. Experiments with a model protein (bovine serum albumin) and cells (L929 mouse fibroblasts) on patterned surfaces show that proteins and cells only adhere on the patterns, whereas the background stays uncovered.
A method for fabricating chemically nanopatterned surfaces based on a combination of colloidal lithography and plasma‐ enhanced chemical vapor deposition (PECVD) is presented. This method can be applied for the creation of different nanopatterns, and it is in principle not limited in patterning resolution. Nanocraters of poly(acrylic acid) (carboxylic moieties) surrounded by a matrix of poly(ethylene glycol) are fabricated. Chemical force microscopy demonstrates that the process is able to produce the expected surface chemical contrast. Finally, the carboxylic groups of the craters are activated in order to induce the covalent binding of fluorescent‐labeled proteins. Fluorescence investigation using scanning confocal microscopy shows that the proteins are preferentially attached inside the functional craters.
The H 2 bubbles resulting from the reaction of freshly prepared Si powders with water were found to impede the large-scale preparation of aqueous-based Si/CMC (Na-Carboxy-Methyl-Cellulose)/C slurries and could consequently prevent the large-scale production of composite electrode films. To understand and possibly control this reaction, silicon particles (Si ref ) have been partially oxidized either by contact with water or by air heating at elevated temperatures. By coupling kinetics, XRD, (HR)TEM/EELS, TGA/DSC, IR and gas adsorption data, the porosity/texture/surface chemistry of the resulting silica-based coating layers were found to be highly dependent on the oxidation process, while the extent of oxidation is tuned by the time-temperature of the treatment. Although fully oxidized samples are totally inactive vs. Li, the high porosity of the water-formed silica coating contrasts with the dense air-formed one that can limit access to the Si core and can block its reactivity if too thick. Controlled and optimized air-oxidative pre-treatments can prevent the H 2 evolution during the slurry preparation, hence enabling the reproducible production of high-quality electrode coatings on Cu current collectors. Such treatments do not impact the reversibility of the Si-Li electrochemical reaction, even with no capacity constraints and with or without FEC addition in commercial EC/DMC/LiPF 6 electrolytes.
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