Chemically modified silica materials as model systems for the characterization of water-surfaceinteractions

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The aim of this project is the controlled modification of the surfaces of mesoporous silica and carbon materials and the investigation of the influence of these modifications on the structure, dynamics and phase behavior of simple and binary fluids confined in the pores using methods of solidstate NMR spectroscopy. Owing to the presence of the surface silanol groups, the surface properties (hydrophilic / hydrophobic, polar / non-polar, hydrogen-bond donors/acceptors) of the silica materials can be relatively easily chemically functionalized, as for example with amino,amide, carboxyl, phosphate, chloride or peptide functions. The surface properties of the carbon materials are controlled by the selection of the temperature where the carbonization is carried out. The quality of the modified materials is controlled by BET, SAXS, solid-state MAS NMR spectroscopy and dynamic nuclear polarization. The behavior of the fluids in the pores is studied by 1H-and 2H-MASNMR measurements. In the binary mixtures we are primarily interested in the dynamic processes in the interface layer. These are analyzed by a combination of 1H-MAS and 2H-MAS NMR with 2H and 17O line form analysis. The dynamic behavior of surface modifications (peptide chains and alkyl chains) is investigated by 2H solid-state NMR spectroscopy.