Interface chemistry and molecular bonding of functional ethoxysilane-based self-assembled monolayers on magnesium surfaces.

The modification of magnesium implants with functional organic molecules is important for increasing the biological acceptance and for reducing the corrosion rate of the implant. In this work, we evaluated by a combined experimental and theoretical approach the adsorption strength and geometry of a functional self-assembled monolayer (SAM) of hydrolyzed (3-aminopropyl)triethoxysilane (APTES) molecules on a model magnesium implant surface. In time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS), only a minor amount of reverse attachment was observed.

Tuning the growth orientation of epitaxial films by interface chemistry.

The support of epitaxial films frequently determines their crystallographic orientation, which is of crucial importance for their properties. We report a novel way to alter the film orientation without changing the substrate. We show for the growth of CoO on the Ir(100) surface that, while the oxide grows in (111) orientation on the bare substrate, the orientation switches to (100) by introducing a single (or a few) monolayer(s) of Co between the oxide and substrate.