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O: Fachverband Oberflächenphysik

O 45: Poster: Solid-Liquid Interfaces - Structure, Spectroscopy, Reactions and Electrochemistry

O 45.15: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

Chemical Functionalization of Oxide Surfaces: Insights into the Mechanism of Molecular Adsorption at the Solid/Liquid Interface — •Paul Schwarz and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg

Oxide surfaces are usually functionalized by attaching strongly interacting linker groups, like phosphonic acid or silanol units, employing wet-chemical processes. To obtain a fundamental understanding of the binding and reaction mechanisms at the solid/liquid interface we performed ab initio molecular dynamics (AIMD) simulations to study the anchoring of methylsilanetriol (MST) to aluminum oxide surfaces via condensation reactions in the presence of residual water and liquid isopropanol. Applying Thermodynamic Integration (TI) and Umbrella Sampling (US), we calculated the activation barrier for the surface binding of MST. Depending on whether residual water is present or not, the condensation reaction is found to be spontaneous or activated. Spontaneous condensation can proceed in two different ways, either by an initial protonation of an OH group of the surface or of the MST molecule. In the first case, an intermediate six-membered ring between MST and the desorbing water molecule is formed. In contrast, the protonation of an OH group of MST results in a penta-coordinated Si atom, where the surface OH group at the adsorption site is substituting the leaving OH group of MST.