| Abstract
| - A new kind of multilayers based on metal-ion coordination was constructed on gold surfaces, wheremolecular layers are successively added using a highly controlled step-by-step procedure. A bifunctional ligandis used as the base layer, bearing a cyclic disulfide group to attach to the gold surface and a bishydroxamategroup capable of ion binding. An 8-coordinating metal ion such as Zr4+ or Ce4+ is then coordinated to thebishydroxamate site, followed by exposure to a second ligand possessing four hydroxamate groups. Thetetrahydroxamate molecule ligates to the metal ion (bound to the base layer) using two of its four hydroxamategroups and is free to bind a second metal ion at its other end. A sequence of adsorption steps using metal ionsand tetrahydroxamate ligands was carried out, resulting in an ordered metal−organic multilayer. Multilayerstructures comprising up to 10 tetrahydroxamate/metal ion layers were constructed, with full characterizationat each step of multilayer formation using ellipsometry, contact angle measurements, X-ray photoelectronspectroscopy, and Fourier transform infrared spectroscopy. The multilayer morphology and mechanical propertieswere studied by scanning force microscopy. It is shown that different base ligands induce dramatic differencesin the morphology and stiffness of the final multilayer. The possibility to construct segmented multilayerscontaining Zr4+ and Ce4+ ions at defined locations is presented.
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