Surface properties of rutile and its modified form -: Part 2.: Characteristics of the water/solid interface as examined by means of 1H-NMR spectroscopy with bulk freezing

Changes in the excess Gibbs energy of water at the water/solid interface as a function of the film thickness of water perturbed by the solid surface of titanium dioxide (rutile form) and this sample modified by sequential coating with amorphous Al2O3 (48 w/w) and SiO2 (2% w/w) were determined for aqueous and deuterochloroform suspensions of these solids by means of H-1-NMR spectroscopy with bulk freezing. This modification led to a dramatic enhancement of the total excess Gibbs energy of water at the water/solid interface as well as of the thickness of the interface water layer. The increase of this thickness is related to the increase of the dispersive component of the surface free energy of the parent and the mixed Si, Ti, and Al oxides as determined from the inverse gas chromatographic data for the adsorption of n-alkanes.