We report the patterning of copper surfaces which display both superhydrophobicity and high adhesion thanks to a new feature geometry, and without resorting to chemical modification. Polystyrene beads organized in 2D crystals under an AC electric field act as a template for the growth of copper deposited via cupric ion-loaded multi-lamellar vesicles. After the removal of the beads, hexagonal arrays of supported hollow spheres or copper bowls are generated, depending on the amount of deposited copper. While the bowl-covered surfaces display a predictable decreasing wettability (Cassie model) as their wall height increases, the hollow sphere-covered surfaces exhibit both high adhesion and superhydrophobicity (Cassie-Baxter state).
5 pagesInternational audienceWe report a new soft lithography approach which only requires colloidal particles and tension generators. This process, named electro-colloidal lithography, is based on the behavior of colloidal assemblies submitted to electric fields generated by alternative current (AC) and direct current (DC). Its advantages are its low cost, fastness and easiness. As an illustration, hexagonal arrays of metal nano-rings, and hexagonal arrays of conductive holes into a contiguous or particle-made polymer matrix were produced. We show how to control separately and finely both the inter-structure separation and the structure morphology (diameter, height, thickness) in a very simple manner. Commercial colloidal particles (polystyrene beads) and synthesized colloidal particles (surfactantmade multilamellar vesicles) were both successfully tested for surface patterning showing the universality/adaptability of this technique
This article describes a general method for the deposition of gold nanoparticles onto solid support based on the use of multilamellar vesicles (MLVs). Gold nanoparticles (nps) synthesized within lipid-based MLVs by UVor γ-irradiation were deposited onto TiO 2 powder support. The organic phase from MLVs was removed by calcination leading to high dispersion of naked Au nanoparticles. The resulting particles were investigated using spectrometry, electron microscopy and XPS. The gold nanoparticles were stable and well-separated on the titania surface. It was found that the metal nanoparticles produced by radiolysis have smaller average size and narrower size distribution than those synthesized by photochemical route. After calcinations, the particles tended to enlarge to reach c.a. 18 nm. The gold loading on the titania support could be controlled by changing the gold salt concentration and the MLV-toTiO 2 weight ratio; values of Au-to-Ti ratio up to 44 % could be obtained.
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