SURFACE-PROPERTIES OF RUTILE AND ITS MODIFIED FORM - PART 2 - CHARACTERISTICS OF THE WATER SOLID INTERFACE AS EXAMINED BY MEANS OF H-1-NMR SPECTROSCOPY WITH BULK FREEZING/

Changes in the excess Gibbs energy of water at the water/solid interfa ce 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) we re determined for aqueous and deuterochloroform suspensions of these s olids by means of H-1-NMR spectroscopy with bulk freezing. This modifi cation 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 t he interface water layer. The increase of this thickness is related to the increase of the dispersive component of the surface free energy o f the parent and the mixed Si, Ti, and Al oxides as determined from th e inverse gas chromatographic data for the adsorption of n-alkanes.