Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 30: Inorganic/Organic Interfaces: Towards Application

O 30.8: Talk

Tuesday, March 17, 2015, 15:45–16:00, MA 043

Modeling of air exposed titanium dioxide — Wenke Friedrichs, Norman Geist, Dennis Sandvoß, and •Walter Langel — Institut für Biochemie, Universität Greifswald, 17489 Greifswald

Adhesion of biomolecules to inorganic surfaces is of condsiderable interest for medical applications. We report a classical molecular dynamics study of peptides on titanium dioxide. Previous work refers to clean hydroxylated surfaces mimicking UHV-preparation. Air exposed Ti is not only passivated and partially hydroxylated but also covered by a hydrocarbon film making it more hydrophobic than a polar metal oxide. A computational model for this contamination must be based on volatile organic compounds in atmosphere, which screen the hydrophilic surface and are poorly soluble in water films on it. We report simulations of pentanol layers of various mass coverage on a variety of TiO2-surfaces. Physisorbed layers are stable, and their contact angles match experimental data. * On the clean hydroxylated surfaces most peptides easily adsorb in the simulation due to polar groups. In contrast to other work we can trace hindering of adsorption by the hydrocarbons working as a microscopic wax.Only partly hydrophobic species penetrate the contamination and attach due to polar groups, and this behavior seems to be correlated with the partition coefficient of the peptide. This result should have impact on several applications of titanium dioxide.